Features • MPEG I/II-Layer 3 Hardwired Decoder • • • • • • • • • • • • • • • • • • • • • – Stand-alone MP3 Decoder – 48, 44.1, 32, 24, 22.05, 16 kHz Sampling Frequency – Separated Digital Volume Control on Left and Right Channels (Software Control using 31 Steps) – Bass, Medium, and Treble Control (31 Steps) – Bass Boost Sound Effect – Ancillary Data Extraction – CRC Error and MPEG Frame Synchronization Indicators Programmable Audio Output for Interfacing with Common Audio DAC – PCM Format Compatible – I2S Format Compatible 8-bit MCU C51 Core Based (FMAX = 20 MHz) 2304 Bytes of Internal RAM 64K Bytes of Code Memory – AT89C51SND1C: Flash (100K Erase/Write Cycles) – AT83SND1C: ROM 4K Bytes of Boot Flash Memory (AT89C51SND1C) – ISP: Download from USB (standard) or UART (option) External Code Memory – AT80C51SND1C: ROMless USB Rev 1.1 Controller – Full Speed Data Transmission Built-in PLL – MP3 Audio Clocks – USB Clock MultiMedia Card® Interface Compatibility Atmel DataFlash® SPI Interface Compatibility IDE/ATAPI Interface 2 Channels 10-bit ADC, 8 kHz (8-true bit) – Battery Voltage Monitoring – Voice Recording Controlled by Software Up to 44 Bits of General-purpose I/Os – 4-bit Interrupt Keyboard Port for a 4 x n Matrix – SmartMedia® Software Interface 2 Standard 16-bit Timers/Counters Hardware Watchdog Timer Standard Full Duplex UART with Baud Rate Generator Two Wire Master and Slave Modes Controller SPI Master and Slave Modes Controller Power Management – Power-on Reset – Software Programmable MCU Clock – Idle Mode, Power-down Mode Operating Conditions: – 3V, ±10%, 25 mA Typical Operating at 25°C – Temperature Range: -40°C to +85°C Packages – TQFP80, BGA81, PLCC84 (Development Board) – Dice Single-Chip Flash Microcontroller with MP3 Decoder and Human Interface AT83SND1C AT89C51SND1C AT80C51SND1C 4109J–8051–10/06 1. Description The AT8xC51SND1C are fully integrated stand-alone hardwired MPEG I/II-Layer 3 decoder with a C51 microcontroller core handling data flow and MP3-player control. The AT89C51SND1C includes 64K Bytes of Flash memory and allows In-System Programming through an embedded 4K Bytes of Boot Flash memory. The AT83SND1C includes 64K Bytes of ROM memory. The AT80C51SND1C does not include any code memory. The AT8xC51SND1C include 2304 Bytes of RAM memory. The AT8xC51SND1C provides the necessary features for human interface like timers, keyboard port, serial or parallel interface (USB, TWI, SPI, IDE), ADC input, I2S output, and all external memory interface (NAND or NOR Flash, SmartMedia, MultiMedia, DataFlash cards). 2. Typical Applications • MP3-Player • PDA, Camera, Mobile Phone MP3 • Car Audio/Multimedia MP3 • Home Audio/Multimedia MP3 3. Block Diagram Figure 3-1. AT8xC51SND1C Block Diagram INT0 INT1 3 3 VDD VSS UVDD UVSS AVDD AVSS AREF AIN1:0 Interrupt Handler Unit RAM 2304 Bytes C51 (X2 Core) Clock and PLL Unit Flash ROM 64 KBytes Flash Boot 4 KBytes 10-bit A to D Converter TXD RXD T0 T1 SS MISO MOSI SCK SCL SDA 3 3 3 4 1 3 UART and BRG Timers 0/1 Watchdog 4 4 4 SPI/DataFlash Controller 1 TWI Controller 8-Bit Internal Bus MP3 Decoder Unit I2S/PCM Audio Interface USB Controller MMC Interface Keyboard Interface I/O Ports IDE Interface 1 FILT X1 X2 RST ISP ALE DOUT DCLK DSEL SCLK D+ D- MCLK MDAT MCMD KIN3:0 P0-P5 1 Alternate function of Port 1 3 Alternate function of Port 3 4 Alternate function of Port 4 2 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 4. Pin Description 4.1 Pinouts AT8xC51SND1C 80-pin QFP Package 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 P5.1 P5.0 P0.0/AD0 P0.1/AD1 P0.2/AD2 P0.3/AD3 P0.4/AD4 P0.5/AD5 VSS VDD P0.6/AD6 P0.7/AD7 P4.3/SS P4.2/SCK P4.1/MOSI P4.0/MISO P2.0/A8 P2.1/A9 P4.7 P4.6 Figure 4-1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 AT89C51SND1C-RO (FLASH) AT83SND1C-RO (ROM) AT80C51SND1C-RO (ROMLESS) 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 P4.5 P4.4 P2.2/A10 P2.3/A11 P2.4/A12 P2.5/A13 P2.6/A14 P2.7/A15 VSS VDD MCLK MDAT MCMD RST SCLK DSEL DCLK DOUT VSS VDD D+ DVDD VSS P3.0/RXD P3.1/TXD P3.2/INT0 P3.3/INT1 P3.4/T0 P3.5/T1 P3.6/WR P3.7/RD AVDD AVSS AREFP AREFN AIN0 AIN1 P5.2 P5.3 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 ALE ISP1/PSEN2/NC P1.0/KIN0 P1.1/KIN1 P1.2/KIN2 P1.3/KIN3 P1.4 P1.5 P1.6/SCL P1.7/SDA VDD PVDD FILT PVSS VSS X2 X1 TST UVDD UVSS Notes: 1. ISP pin is only available in AT89C51SND1C product. Do not connect this pin on AT83SND1C product. 2. PSEN pin is only available in AT80C51SND1C product. 3 4109J–8051–10/06 Figure 4-2. 9 Notes: 4 AT8xC51SND1C 81-pin BGA Package 8 7 6 5 4 P4.6 P2.0/ A8 P4.0/ MISO P4.4 P4.7 P2.5/ A13 3 2 1 P4.2/ SCK VDD P0.2/ AD2 P0.3/ AD3 P5.0 ALE A P4.1/ MOSI P4.3/ SS P0.1/ AD1 P0.4/ AD4 P0.0/ AD0 ISP1/ PSEN2 NC P1.1 B P2.2/ A10 P2.1/ A9 P0.6 VSS P5.1 P1.0/ KIN0 P1.3/ KIN3 P1.2/ KIN2 C P2.4/ A12 P2.6/ A14 P4.5 P0.7/ AD7 P0.5/ AD5 P1.6/ SCL P1.7/ SDA P1.5 P1.4 D VDD P2.3/ A11 VSS P2.7/ A15 FILT PVDD X1 VDD E RST MCMD MCLK MDAT AVDD P3.4/ T0 UVSS PVSS X2 F DSEL SCLK DOUT P5.3 P3.7/ RD P3.5/ T1 VDD TST VSS G DCLK VSS AIN1 AVSS AIN0 P3.3/ INT1 P3.1/ TXD D- UVDD H VDD P5.2 AREFP AREFN P3.6/ WR P3.2/ INT0 P3.0/ RXD VSS D+ J 1. ISP pin is only available in AT89C51SND1C product. Do not connect this pin on AT83SND1C and AT80C51SND1C product. 2. PSEN pin is only available in AT80C51SND1C product. AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C AT8xC51SND1C 84-pin PLCC Package 11 10 9 8 7 6 5 4 3 2 1 84 83 82 81 80 79 78 77 76 75 NC P5.1 P5.0 P0.0/AD0 P0.1/AD1 P0.2/AD2 P0.3/AD3 P0.4/AD4 P0.5/AD5 VSS VDD P0.6/AD6 P0.7/AD7 P4.3/SS P4.2/SCK P4.1/MOSI P4.0/MISO P2.0/A8 P2.1/A9 P4.7 P4.6 Figure 4-3. 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 AT89C51SND1C-SR (FLASH) 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 NC P4.5 P4.4 P2.2/A10 P2.3/A11 P2.4/A12 P2.5/A13 P2.6/A14 P2.7/A15 VSS VDD MCLK MDAT MCMD RST SCLK DSEL DCLK DOUT VSS VDD D+ DVDD VSS P3.0/RXD P3.1/TXD P3.2/INT0 P3.3/INT1 P3.4/T0 P3.5/T1 P3.6/WR P3.7/RD AVDD AVSS AREFP AREFN AIN0 AIN1 P5.2 P5.3 NC 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 ALE ISP P1.0/KIN0 P1.1/KIN1 P1.2/KIN2 P1.3/KIN3 P1.4 P1.5 P1.6/SCL P1.7/SDA VDD PAVDD FILT PAVSS VSS X2 NC X1 TST UVDD UVSS 4.2 Signals All the AT8xC51SND1C signals are detailed by functionality in Table 1 to Table 14. Table 1. Ports Signal Description Signal Name Type Description Alternate Function P0.7:0 I/O Port 0 P0 is an 8-bit open-drain bidirectional I/O port. Port 0 pins that have 1s written to them float and can be used as high impedance inputs. To avoid any parasitic current consumption, floating P0 inputs must be polarized to VDD or VSS. P1.7:0 I/O Port 1 P1 is an 8-bit bidirectional I/O port with internal pull-ups. KIN3:0 SCL SDA P2.7:0 I/O Port 2 P2 is an 8-bit bidirectional I/O port with internal pull-ups. A15:8 AD7:0 5 4109J–8051–10/06 Signal Name Type Alternate Function Description RXD TXD INT0 INT1 T0 T1 WR RD I/O Port 3 P3 is an 8-bit bidirectional I/O port with internal pull-ups. P4.7:0 I/O Port 4 P4 is an 8-bit bidirectional I/O port with internal pull-ups. MISO MOSI SCK SS P5.3:0 I/O Port 5 P5 is a 4-bit bidirectional I/O port with internal pull-ups. - P3.7:0 Table 2. Clock Signal Description Signal Name Type Alternate Function Description X1 I Input to the on-chip inverting oscillator amplifier To use the internal oscillator, a crystal/resonator circuit is connected to this pin. If an external oscillator is used, its output is connected to this pin. X1 is the clock source for internal timing. X2 O Output of the on-chip inverting oscillator amplifier To use the internal oscillator, a crystal/resonator circuit is connected to this pin. If an external oscillator is used, leave X2 unconnected. - FILT I PLL Low Pass Filter input FILT receives the RC network of the PLL low pass filter. - - Table 3. Timer 0 and Timer 1 Signal Description Signal Name Type Alternate Function Description Timer 0 Gate Input INT0 serves as external run control for timer 0, when selected by GATE0 bit in TCON register. INT0 I External Interrupt 0 INT0 input sets IE0 in the TCON register. If bit IT0 in this register is set, bit IE0 is set by a falling edge on INT0. If bit IT0 is cleared, bit IE0 is set by a low level on INT0. P3.2 Timer 1 Gate Input INT1 serves as external run control for timer 1, when selected by GATE1 bit in TCON register. INT1 6 I External Interrupt 1 INT1 input sets IE1 in the TCON register. If bit IT1 in this register is set, bit IE1 is set by a falling edge on INT1. If bit IT1 is cleared, bit IE1 is set by a low level on INT1. P3.3 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Signal Name Type T0 I Timer 0 External Clock Input When timer 0 operates as a counter, a falling edge on the T0 pin increments the count. P3.4 T1 I Timer 1 External Clock Input When timer 1 operates as a counter, a falling edge on the T1 pin increments the count. P3.5 Description Alternate Function Table 4. Audio Interface Signal Description Signal Name Type DCLK O DAC Data Bit Clock - DOUT O DAC Audio Data - DSEL O DAC Channel Select Signal DSEL is the sample rate clock output. - SCLK O DAC System Clock SCLK is the oversampling clock synchronized to the digital audio data (DOUT) and the channel selection signal (DSEL). - Description Alternate Function Table 5. USB Controller Signal Description Signal Name Type D+ I/O USB Positive Data Upstream Port This pin requires an external 1.5 KΩ pull-up to VDD for full speed operation. - D- I/O USB Negative Data Upstream Port - Description Alternate Function Table 6. MutiMediaCard Interface Signal Description Signal Name Type MCLK O MMC Clock output Data or command clock transfer. - MCMD I/O MMC Command line Bidirectional command channel used for card initialization and data transfer commands. To avoid any parasitic current consumption, unused MCMD input must be polarized to VDD or VSS. - MDAT I/O MMC Data line Bidirectional data channel. To avoid any parasitic current consumption, unused MDAT input must be polarized to VDD or VSS. - Description Alternate Function 7 4109J–8051–10/06 Table 7. UART Signal Description Signal Name Type Alternate Function RXD I/O Receive Serial Data RXD sends and receives data in serial I/O mode 0 and receives data in serial I/O modes 1, 2 and 3. P3.0 TXD O Transmit Serial Data TXD outputs the shift clock in serial I/O mode 0 and transmits data in serial I/O modes 1, 2 and 3. P3.1 Description Table 8. SPI Controller Signal Description Signal Name Type Alternate Function MISO I/O SPI Master Input Slave Output Data Line When in master mode, MISO receives data from the slave peripheral. When in slave mode, MISO outputs data to the master controller. P4.0 MOSI I/O SPI Master Output Slave Input Data Line When in master mode, MOSI outputs data to the slave peripheral. When in slave mode, MOSI receives data from the master controller. P4.1 SCK I/O SPI Clock Line When in master mode, SCK outputs clock to the slave peripheral. When in slave mode, SCK receives clock from the master controller. P4.2 SS I SPI Slave Select Line When in controlled slave mode, SS enables the slave mode. P4.3 Description Table 9. TWI Controller Signal Description Signal Name Type Alternate Function Description SCL I/O TWI Serial Clock When TWI controller is in master mode, SCL outputs the serial clock to the slave peripherals. When TWI controller is in slave mode, SCL receives clock from the master controller. SDA I/O TWI Serial Data SDA is the bidirectional Two Wire data line. P1.6 P1.7 Table 10. A/D Converter Signal Description 8 Signal Name Type AIN1:0 I A/D Converter Analog Inputs - AREFP I Analog Positive Voltage Reference Input - AREFN I Analog Negative Voltage Reference Input This pin is internally connected to AVSS. - Description Alternate Function AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Table 11. Keypad Interface Signal Description Signal Name Type KIN3:0 I Description Keypad Input Lines Holding one of these pins high or low for 24 oscillator periods triggers a keypad interrupt. Alternate Function P1.3:0 Table 12. External Access Signal Description Notes: Signal Name Type A15:8 I/O Address Lines Upper address lines for the external bus. Multiplexed higher address and data lines for the IDE interface. P2.7:0 AD7:0 I/O Address/Data Lines Multiplexed lower address and data lines for the external memory or the IDE interface. P0.7:0 ALE O Address Latch Enable Output ALE signals the start of an external bus cycle and indicates that valid address information is available on lines A7:0. An external latch is used to demultiplex the address from address/data bus. - PSEN I/O Program Store Enable Output (AT80C51SND1C Only) This signal is active low during external code fetch or external code read (MOVC instruction). - ISP I/O ISP Enable Input (AT89C51SND1C Only) This signal must be held to GND through a pull-down resistor at the falling reset to force execution of the internal bootloader. - RD O Read Signal Read signal asserted during external data memory read operation. P3.7 WR O Write Signal Write signal asserted during external data memory write operation. P3.6 EA(1)(2) I External Access Enable (Dice Only) EA must be externally held low to enable the device to fetch code from external program memory locations 0000h to FFFFh. Description Alternate Function - 1. For ROM/Flash Dice product versions: pad EA must be connected to VCC. 2. For ROMless Dice product versions: pad EA must be connected to VSS. Table 13. System Signal Description Signal Name Type Description RST I Reset Input Holding this pin high for 64 oscillator periods while the oscillator is running resets the device. The Port pins are driven to their reset conditions when a voltage lower than VIL is applied, whether or not the oscillator is running. This pin has an internal pull-down resistor which allows the device to be reset by connecting a capacitor between this pin and VDD. Asserting RST when the chip is in Idle mode or Power-Down mode returns the chip to normal operation. TST I Test Input Test mode entry signal. This pin must be set to VDD. Alternate Function - - 9 4109J–8051–10/06 Table 14. Power Signal Description 10 Signal Name Type Description Alternate Function VDD PWR Digital Supply Voltage Connect these pins to +3V supply voltage. - VSS GND Circuit Ground Connect these pins to ground. - AVDD PWR Analog Supply Voltage Connect this pin to +3V supply voltage. - AVSS GND Analog Ground Connect this pin to ground. - PVDD PWR PLL Supply voltage Connect this pin to +3V supply voltage. - PVSS GND PLL Circuit Ground Connect this pin to ground. - UVDD PWR USB Supply Voltage Connect this pin to +3V supply voltage. - UVSS GND USB Ground Connect this pin to ground. - AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 4.3 Internal Pin Structure Table 15. Detailed Internal Pin Structure Circuit(1) Type Pins Input TST Input/Output RST Input/Output P1(2) P2(3) P3 P4 P53:0 RTST VDD VDD P RRST Watchdog Output VSS 2 osc periods Latch Output VDD VDD VDD P1 P2 P3 N VSS VDD P Input/Output P0 MCMD MDAT ISP N PSEN VSS ALE SCLK DCLK VDD P Output N DOUT DSEL MCLK VSS D+ Input/Output D+ D- D- Notes: 1. For information on resistors value, input/output levels, and drive capability, refer to the Section “DC Characteristics”, page 180. 2. When the Two Wire controller is enabled, P1, P2, and P3 transistors are disabled allowing pseudo open-drain structure. 3. In Port 2, P1 transistor is continuously driven when outputting a high level bit address (A15:8). 11 4109J–8051–10/06 5. Clock Controller The AT8xC51SND1C clock controller is based on an on-chip oscillator feeding an on-chip Phase Lock Loop (PLL). All internal clocks to the peripherals and CPU core are generated by this controller. 5.1 Oscillator The AT8xC51SND1C X1 and X2 pins are the input and the output of a single-stage on-chip inverter (see Figure 5-1) that can be configured with off-chip components such as a Pierce oscillator (see Figure 5-2). Value of capacitors and crystal characteristics are detailed in the Section “DC Characteristics”, page 163. The oscillator outputs three different clocks: a clock for the PLL, a clock for the CPU core, and a clock for the peripherals as shown in Figure 5-1. These clocks are either enabled or disabled, depending on the power reduction mode as detailed in the section “Power Management” on page 47. The peripheral clock is used to generate the Timer 0, Timer 1, MMC, ADC, SPI, and Port sampling clocks. Figure 5-1. Oscillator Block Diagram and Symbol ÷2 X1 0 Peripheral Clock 1 CPU Core Clock X2 X2 CKCON.0 IDL PCON.0 PD Oscillator Clock PCON.1 PER CLOCK CPU CLOCK Peripheral Clock Symbol Figure 5-2. OSC CLOCK CPU Core Clock Symbol Oscillator Clock Symbol Crystal Connection X1 C1 Q C2 VSS 5.2 X2 X2 Feature Unlike standard C51 products that require 12 oscillator clock periods per machine cycle, the AT8xC51SND1C need only 6 oscillator clock periods per machine cycle. This feature called the “X2 feature” can be enabled using the X2 bit (1) in CKCON (see Table 16) and allows the AT8xC51SND1C to operate in 6 or 12 oscillator clock periods per machine cycle. As shown in Figure 5-1, both CPU and peripheral clocks are affected by this feature. Figure 5-3 shows the X2 mode switching waveforms. After reset the standard mode is activated. In standard mode the CPU and peripheral clock frequency is the oscillator frequency divided by 2 while in X2 mode, it 12 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C is the oscillator frequency. Note: 1. The X2 bit reset value depends on the X2B bit in the Hardware Security Byte (see Table 12 on page 24). Using the AT89C51SND1C (Flash Version) the system can boot either in standard or X2 mode depending on the X2B value. Using AT83SND1C (ROM Version) the system always boots in standard mode. X2B bit can be changed to X2 mode later by software. Figure 5-3. Mode Switching Waveforms X1 X1 ÷ 2 X2 Bit Clock STD Mode Note: 5.3 5.3.1 X2 Mode(1) STD Mode 1. In order to prevent any incorrect operation while operating in X2 mode, user must be aware that all peripherals using clock frequency as time reference (timers, etc.) will have their time reference divided by 2. For example, a free running timer generating an interrupt every 20 ms will then generate an interrupt every 10 ms. PLL PLL Description The AT8xC51SND1C PLL is used to generate internal high frequency clock (the PLL Clock) synchronized with an external low-frequency (the Oscillator Clock). The PLL clock provides the MP3 decoder, the audio interface, and the USB interface clocks. Figure 5-4 shows the internal structure of the PLL. The PFLD block is the Phase Frequency Comparator and Lock Detector. This block makes the comparison between the reference clock coming from the N divider and the reverse clock coming from the R divider and generates some pulses on the Up or Down signal depending on the edge position of the reverse clock. The PLLEN bit in PLLCON register is used to enable the clock generation. When the PLL is locked, the bit PLOCK in PLLCON register (see Table 17) is set. The CHP block is the Charge Pump that generates the voltage reference for the VCO by injecting or extracting charges from the external filter connected on PFILT pin (see Figure 5-5). Value of the filter components are detailed in the Section “DC Characteristics”. The VCO block is the Voltage Controlled Oscillator controlled by the voltage Vref produced by the charge pump. It generates a square wave signal: the PLL clock. 13 4109J–8051–10/06 Figure 5-4. PLL Block Diagram and Symbol PFILT PLLCON.1 PLLEN N divider OSC CLOCK Up N6:0 PFLD CHP Vref PLL Clock VCO Down PLOCK R divider PLLCON.0 R9:0 PLL CLOCK OSCclk × ( R + 1 ) PLLclk = ----------------------------------------------N+1 PLL Clock Symbol Figure 5-5. PLL Filter Connection FILT R C2 C1 VSS 5.3.2 VSS PLL Programming The PLL is programmed using the flow shown in Figure 5-6. As soon as clock generation is enabled, the user must wait until the lock indicator is set to ensure the clock output is stable. The PLL clock frequency will depend on MP3 decoder clock and audio interface clock frequencies. Figure 5-6. PLL Programming Flow PLL Programming Configure Dividers N6:0 = xxxxxxb R9:0 = xxxxxxxxxxb Enable PLL PLLRES = 0 PLLEN = 1 PLL Locked? PLOCK = 1? 14 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 5.4 Registers Table 16. CKCON Register CKCON (S:8Fh) – Clock Control Register 7 6 5 4 3 2 1 0 TWIX2 WDX2 - SIX2 - T1X2 T0X2 X2 Bit Number Bit Mnemonic Description TWIX2 Two-Wire Clock Control Bit Set to select the oscillator clock divided by 2 as TWI clock input (X2 independent). Clear to select the peripheral clock as TWI clock input (X2 dependent). 6 WDX2 Watchdog Clock Control Bit Set to select the oscillator clock divided by 2 as watchdog clock input (X2 independent). Clear to select the peripheral clock as watchdog clock input (X2 dependent). 5 - 7 4 SIX2 3 - 2 1 0 Reserved The values read from this bit is indeterminate. Do not set this bit. Enhanced UART Clock (Mode 0 and 2) Control Bit Set to select the oscillator clock divided by 2 as UART clock input (X2 independent). Clear to select the peripheral clock as UART clock input (X2 dependent).. Reserved The values read from this bit is indeterminate. Do not set this bit. T1X2 Timer 1 Clock Control Bit Set to select the oscillator clock divided by 2 as timer 1 clock input (X2 independent). Clear to select the peripheral clock as timer 1 clock input (X2 dependent). T0X2 Timer 0 Clock Control Bit Set to select the oscillator clock divided by 2 as timer 0 clock input (X2 independent). Clear to select the peripheral clock as timer 0 clock input (X2 dependent). X2 System Clock Control Bit Clear to select 12 clock periods per machine cycle (STD mode, FCPU = FPER = FOSC/2). Set to select 6 clock periods per machine cycle (X2 mode, FCPU = FPER = FOSC). Reset Value = 0000 000Xb (AT89C51SND1C) or 0000 0000b (AT83SND1C) Table 17. PLLCON Register PLLCON (S:E9h) – PLL Control Register 7 6 5 4 3 2 1 0 R1 R0 - - PLLRES - PLLEN PLOCK Bit Number Bit Mnemonic Description 7-6 R1:0 5-4 - 3 PLLRES PLL Least Significant Bits R Divider 2 LSB of the 10-bit R divider. Reserved The values read from these bits are always 0. Do not set these bits. PLL Reset Bit Set this bit to reset the PLL. Clear this bit to free the PLL and allow enabling. 15 4109J–8051–10/06 Bit Number Bit Mnemonic Description Reserved The value read from this bit is always 0. Do not set this bit. 2 - 1 PLLEN PLL Enable Bit Set to enable the PLL. Clear to disable the PLL. 0 PLOCK PLL Lock Indicator Set by hardware when PLL is locked. Clear by hardware when PLL is unlocked. Reset Value = 0000 1000b Table 18. PLLNDIV Register PLLNDIV (S:EEh) – PLL N Divider Register 7 6 5 4 3 2 1 0 - N6 N5 N4 N3 N2 N1 N0 Bit Number Bit Mnemonic Description 7 - 6-0 N6:0 Reserved The value read from this bit is always 0. Do not set this bit. PLL N Divider 7 - bit N divider. Reset Value = 0000 0000b Table 19. PLLRDIV Register PLLRDIV (S:EFh) – PLL R Divider Register 7 6 5 4 3 2 1 0 R9 R8 R7 R6 R5 R4 R3 R2 Bit Number 7-0 Bit Mnemonic Description R9:2 PLL Most Significant Bits R Divider 8 MSB of the 10-bit R divider. Reset Value = 0000 0000b 16 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 6. Program/Code Memory The AT8xC51SND1C execute up to 64K Bytes of program/code memory. Figure 6-1 shows the split of internal and external program/code memory spaces depending on the product. The AT83SND1C product provides the internal program/code memory in ROM memory while the AT89C51SND1C product provides it in Flash memory. These 2 products do not allow external code memory execution. External code memory execution is achieved using the AT80C51SND1C product which does not provide any internal program/code memory. The Flash memory increases EPROM and ROM functionality by in-circuit electrical erasure and programming. The high voltage needed for programming or erasing Flash cells is generated onchip using the standard VDD voltage, made possible by the internal charge pump. Thus, the AT89C51SND1C can be programmed using only one voltage and allows In-application software programming. Hardware programming mode is also available using common programming tools. See the application note ‘Programming T89C51x and AT89C51x with Device Programmers’. The AT89C51SND1C implements an additional 4K Bytes of on-chip boot Flash memory provided in Flash memory. This boot memory is delivered programmed with a standard boot loader software allowing In-System Programming (ISP). It also contains some Application Programming Interface routines named API routines allowing In Application Programming (IAP) by using user’s own boot loader. Figure 6-1. Program/Code Memory Organization FFFFh FFFFh 64K Bytes External Code 0000h 6.1 FFFFh F000h F000h 64K Bytes Code ROM 0000h AT80C51SND1C FFFFh 4K Bytes Boot Flash 64K Bytes Code Flash 0000h AT83SND1C AT89C51SND1C ROMLESS Memory Architecture As shown in Figure 6-2 the AT80C51SND1C external memory is composed of one space detailed in the following paragraph. 1 4109J–8051–10/06 Figure 6-2. AT80C51SND1C Memory Architecture FFFFh 64K Bytes User External Memory 0000h 6.1.1 User Space This space is composed of a 64K Bytes code (Flash, EEPROM, EPROM…) memory. It contains the user’s application code. 6.1.2 Memory Interface The external memory interface comprises the external bus (port 0 and port 2) as well as the bus control signals (PSEN, and ALE). Figure 6-3 shows the structure of the external address bus. P0 carries address A7:0 while P2 carries address A15:8. Data D7:0 is multiplexed with A7:0 on P0. Table 6-3 describes the external memory interface signals. Figure 6-3. External Code Memory Interface Structure Flash EPROM AT80C51SND1C A15:8 P2 A15:8 ALE P0 AD7:0 Latch A7:0 A7:0 D7:0 PSEN OE Table 20. External Code Memory Interface Signals 2 Signal Name Type Alternate Function A15:8 O Address Lines Upper address lines for the external bus. P2.7:0 AD7:0 I/O Address/Data Lines Multiplexed lower address lines and data for the external memory. P0.7:0 ALE O Address Latch Enable ALE signals indicates that valid address information are available on lines AD7:0. - PSEN O Program Store Enable Output (AT80C51SND1C Only) This signal is active low during external code fetch or external code read (MOVC instruction). - Description AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 6.1.3 External Bus Cycles This section describes the bus cycles the AT80C51SND1C executes to fetch code (see Figure 6-4) in the external program/code memory. External memory cycle takes 6 CPU clock periods. This is equivalent to 12 oscillator clock periods in standard mode or 6 oscillator clock periods in X2 mode. For further information on X2 mode see section “Clock “. For simplicity, the accompanying figure depicts the bus cycle waveforms in idealized form and does not provide precise timing information. For bus cycling parameters refer to the ‘AC-DC parameters’ section. Figure 6-4. External Code Fetch Waveforms CPU Clock ALE PSEN P0 D7:0 PCL P2 PCH 6.2 D7:0 PCL PCH D7:0 PCH ROM Memory Architecture As shown in Figure 6-5 the AT83SND1C ROM memory is composed of one space detailed in the following paragraph. Figure 6-5. AT83SND1C Memory Architecture FFFFh 64K Bytes User ROM Memory 0000h 6.2.1 User Space This space is composed of a 64K Bytes ROM memory programmed during the manufacturing process. It contains the user’s application code. 6.3 Flash Memory Architecture As shown in Figure 6-6 the AT89C51SND1C Flash memory is composed of four spaces detailed in the following paragraphs. 3 4109J–8051–10/06 Figure 6-6. AT89C51SND1C Memory Architecture Hardware Security Extra Row FFFFh FFFFh 4K Bytes Flash Memory F000h Boot 64K Bytes User Flash Memory 0000h 6.3.1 User Space This space is composed of a 64K Bytes Flash memory organized in 512 pages of 128 Bytes. It contains the user’s application code. This space can be read or written by both software and hardware modes. 6.3.2 Boot Space This space is composed of a 4K Bytes Flash memory. It contains the boot loader for In-System Programming and the routines for In Application Programming. This space can only be read or written by hardware mode using a parallel programming tool. 6.3.3 Hardware Security Space This space is composed of one Byte: the Hardware Security Byte (HSB see Table 23) divided in 2 separate nibbles. The MSN contains the X2 mode configuration bit and the Boot Loader Jump Bit as detailed in Section “Boot Memory Execution”, page 5 and can be written by software while the LSN contains the lock system level to protect the memory content against piracy as detailed in Section “Hardware Security System”, page 4 and can only be written by hardware. 6.3.4 Extra Row Space This space is composed of 2 Bytes: 6.4 • The Software Boot Vector (SBV, see Table 24). This Byte is used by the software boot loader to build the boot address. • The Software Security Byte (SSB, see Table 25). This Byte is used to lock the execution of some boot loader commands. Hardware Security System The AT89C51SND1C implements three lock bits LB2:0 in the LSN of HSB (see Table 23) providing three levels of security for user’s program as described in Table 23 while the AT83SND1C is always set in read disabled mode. Level 0 is the level of an erased part and does not enable any security feature. Level 1 locks the hardware programming of both user and boot memories. 4 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Level 2 locks also hardware verifying of both user and boot memories Level 3 locks also the external execution. Table 21. Lock Bit Features(1) Level LB2(2) 6.5 LB0 Internal Execution External Execution Hardware Verifying Hardware Software Programming Programming 0 U U U Enable Enable Enable Enable Enable 1 U U P Enable Enable Enable Disable Enable 2 U P X Enable Enable Disable Disable Enable (3) P X X Enable Disable Disable Disable Enable 3 Notes: LB1 1. U means unprogrammed, P means programmed and X means don’t care (programmed or unprogrammed). 2. LB2 is not implemented in the AT8xC51SND1C products. 3. AT89C51SND1C products are delivered with third level programmed to ensure that the code programmed by software using ISP or user’s boot loader is secured from any hardware piracy. Boot Memory Execution As internal C51 code space is limited to 64K Bytes, some mechanisms are implemented to allow boot memory to be mapped in the code space for execution at addresses from F000h to FFFFh. The boot memory is enabled by setting the ENBOOT bit in AUXR1 (see Figure 22). The three ways to set this bit are detailed in the following sections. 6.5.1 Software Boot Mapping The software way to set ENBOOT consists in writing to AUXR1 from the user’s software. This enables boot loader or API routines execution. 6.5.2 Hardware Condition Boot Mapping The hardware condition is based on the ISP pin. When driving this pin to low level, the chip reset sets ENBOOT and forces the reset vector to F000h instead of 0000h in order to execute the boot loader software. As shown in Figure 6-7 the hardware condition always allows in-system recovery when user’s memory has been corrupted. 6.5.3 Programmed Condition Boot Mapping The programmed condition is based on the Boot Loader Jump Bit (BLJB) in HSB. As shown in Figure 6-7 when this bit is programmed (by hardware or software programming mode), the chip reset set ENBOOT and forces the reset vector to F000h instead of 0000h, in order to execute the boot loader software. 5 4109J–8051–10/06 Figure 6-7. Hardware Boot Process Algorithm RESET Hard Cond? Software Process Hardware Process ISP = L? Prog Cond? BLJB = P? Standard Init ENBOOT = 0 PC = 0000h FCON = F0h Prog Cond Init ENBOOT = 1 PC = F000h FCON = F0h User’s Application Atmel’s Boot Loader Hard Cond Init ENBOOT = 1 PC = F000h FCON = 00h The software process (boot loader) is detailed in the “Boot Loader Datasheet” Document. 6.6 Preventing Flash Corruption See Section “Reset Recommendation to Prevent Flash Corruption”, page 48. 6.7 Registers Table 22. AUXR1 Register AUXR1 (S:A2h) – Auxiliary Register 1 7 6 5 4 3 2 1 0 - - ENBOOT - GF3 0 - DPS Bit Number 7-6 6 Bit Mnemonic Description Reserved The value read from these bits are indeterminate. Do not set these bits. - 1 5 ENBOOT 4 - Enable Boot Flash Set this bit to map the boot Flash in the code space between at addresses F000h to FFFFh. Clear this bit to disable boot Flash. Reserved The value read from this bit is indeterminate. Do not set this bit. AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Bit Number Bit Mnemonic Description General Flag This bit is a general-purpose user flag. 3 GF3 2 0 Always Zero This bit is stuck to logic 0 to allow INC AUXR1 instruction without affecting GF3 flag. 1 - Reserved for Data Pointer Extension. 0 DPS Data Pointer Select Bit Set to select second data pointer: DPTR1. Clear to select first data pointer: DPTR0. Reset Value = XXXX 00X0b Note: 6.8 1. ENBOOT bit is only available in AT89C51SND1C product. Hardware Bytes Table 23. HSB Byte – Hardware Security Byte 7 6 5 4 3 2 1 0 X2B BLJB - - - LB2 LB1 LB0 Bit Number 7 6 Bit Mnemonic Description X2B(1) (2) BLJB 5-4 - 3 - 2-0 LB2:0 X2 Bit Program this bit to start in X2 mode. Unprogram (erase) this bit to start in standard mode. Boot Loader Jump Bit Program this bit to execute the boot loader at address F000h on next reset. Unprogram (erase) this bit to execute user’s application at address 0000h on next reset. Reserved The value read from these bits is always unprogrammed. Do not program these bits. Reserved The value read from this bit is always unprogrammed. Do not program this bit. Hardware Lock Bits Refer to for bits description. Reset Value = XXUU UXXX, UUUU UUUU after an hardware full chip erase. Note: 1. X2B initializes the X2 bit in CKCON during the reset phase. 2. In order to ensure boot loader activation at first power-up, AT89C51SND1C products are delivered with BLJB programmed. 3. Bits 0 to 3 (LSN) can only be programmed by hardware mode. Table 24. SBV Byte – Software Boot Vector 7 6 5 4 3 2 1 0 ADD15 ADD14 ADD13 ADD12 ADD11 ADD10 ADD9 ADD8 7 4109J–8051–10/06 Bit Number 7-0 Bit Mnemonic Description ADD15:8 MSB of the user’s boot loader 16-bit address location Refer to the boot loader datasheet for usage information (boot loader dependent) Reset Value = XXXX XXXX, UUUU UUUU after an hardware full chip erase. Table 25. SSB Byte – Software Security Byte 7 6 5 4 3 2 1 0 SSB7 SSB6 SSB5 SSB4 SSB3 SSB2 SSB1 SSB0 Bit Number 7-0 Bit Mnemonic Description SSB7:0 Software Security Byte Data Refer to the boot loader datasheet for usage information (boot loader dependent) Reset Value = XXXX XXXX, UUUU UUUU after an hardware full chip erase. 8 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 6. Data Memory The AT8xC51SND1C provides data memory access in 2 different spaces: 1. The internal space mapped in three separate segments: – The lower 128 Bytes RAM segment – The upper 128 Bytes RAM segment – The expanded 2048 Bytes RAM segment 2. The external space. A fourth internal segment is available but dedicated to Special Function Registers, SFRs, (addresses 80h to FFh) accessible by direct addressing mode. For information on this segment, refer to the Section “Special Function Registers”, page 32. Figure 8 shows the internal and external data memory spaces organization. Figure 8. Internal and External Data Memory Organization FFFFh 64K Bytes External XRAM 7FFh FFh 2K Bytes Internal ERAM EXTRAM = 0 00h 6.1 6.1.1 FFh Upper 128 Bytes Internal RAM Indirect Addressing 80h 7Fh 00h Special Function Registers Direct Addressing 80h Lower 128 Bytes Internal RAM Direct or Indirect Addressing 0800h EXTRAM = 1 0000h Internal Space Lower 128 Bytes RAM The lower 128 Bytes of RAM (see Figure 9) are accessible from address 00h to 7Fh using direct or indirect addressing modes. The lowest 32 Bytes are grouped into 4 banks of 8 registers (R0 to R7). 2 bits RS0 and RS1 in PSW register (see Table 18) select which bank is in use according to Table 15. This allows more efficient use of code space, since register instructions are shorter than instructions that use direct addressing, and can be used for context switching in interrupt service routines. Table 15. Register Bank Selection RS1 RS0 Description 0 0 Register bank 0 from 00h to 07h 0 1 Register bank 1 from 08h to 0Fh 1 0 Register bank 2 from 10h to 17h 1 1 Register bank 3 from 18h to 1Fh 25 4109J–8051–10/06 The next 16 Bytes above the register banks form a block of bit-addressable memory space. The C51 instruction set includes a wide selection of single-bit instructions, and the 128 bits in this area can be directly addressed by these instructions. The bit addresses in this area are 00h to 7Fh. Figure 9. Lower 128 Bytes Internal RAM Organization 7Fh 30h 2Fh 20h 18h 10h 08h 00h 6.1.2 Bit-Addressable Space (Bit Addresses 0-7Fh) 1Fh 17h 0Fh 4 Banks of 8 Registers R0-R7 07h Upper 128 Bytes RAM The upper 128 Bytes of RAM are accessible from address 80h to FFh using only indirect addressing mode. 6.1.3 Expanded RAM The on-chip 2K Bytes of expanded RAM (ERAM) are accessible from address 0000h to 07FFh using indirect addressing mode through MOVX instructions. In this address range, EXTRAM bit in AUXR register (see Table 19) is used to select the ERAM (default) or the XRAM. As shown in Figure 8 when EXTRAM = 0, the ERAM is selected and when EXTRAM = 1, the XRAM is selected (see Section “External Space”). The ERAM memory can be resized using XRS1:0 bits in AUXR register to dynamically increase external access to the XRAM space. Table 16 details the selected ERAM size and address range. Table 16. ERAM Size Selection Note: 6.2 6.2.1 XRS1 XRS0 ERAM Size Address 0 0 256 Bytes 0 to 00FFh 0 1 512 Bytes 0 to 01FFh 1 0 1K Byte 0 to 03FFh 1 1 2K Bytes 0 to 07FFh Lower 128 Bytes RAM, Upper 128 Bytes RAM, and expanded RAM are made of volatile memory cells. This means that the RAM content is indeterminate after power-up and must then be initialized properly. External Space Memory Interface The external memory interface comprises the external bus (port 0 and port 2) as well as the bus control signals (RD, WR, and ALE). 26 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 10 shows the structure of the external address bus. P0 carries address A7:0 while P2 carries address A15:8. Data D7:0 is multiplexed with A7:0 on P0. Table 17 describes the external memory interface signals. Figure 10. External Data Memory Interface Structure RAM PERIPHERAL AT8xC51SND1C A15:8 P2 A15:8 ALE P0 AD7:0 Latch A7:0 A7:0 D7:0 RD WR OE WR Table 17. External Data Memory Interface Signals 6.2.2 Signal Name Type A15:8 O Address Lines Upper address lines for the external bus. P2.7:0 AD7:0 I/O Address/Data Lines Multiplexed lower address lines and data for the external memory. P0.7:0 ALE O Address Latch Enable ALE signals indicates that valid address information are available on lines AD7:0. RD O Read Read signal output to external data memory. P3.7 WR O Write Write signal output to external memory. P3.6 Description Alternate Function - Page Access Mode The AT8xC51SND1C implement a feature called Page Access that disables the output of DPH on P2 when executing MOVX @DPTR instruction. Page Access is enable by setting the DPHDIS bit in AUXR register. Page Access is useful when application uses both ERAM and 256 Bytes of XRAM. In this case, software modifies intensively EXTRAM bit to select access to ERAM or XRAM and must save it if used in interrupt service routine. Page Access allows external access above 00FFh address without generating DPH on P2. Thus ERAM is accessed using MOVX @Ri or MOVX @DPTR with DPTR < 0100h, < 0200h, < 0400h or < 0800h depending on the XRS1:0 bits value. Then XRAM is accessed using MOVX @DPTR with DPTR ≥ 0800h regardless of XRS1:0 bits value while keeping P2 for general I/O usage. 6.2.3 External Bus Cycles This section describes the bus cycles the AT8xC51SND1C executes to read (see Figure 11), and write data (see Figure 12) in the external data memory. External memory cycle takes 6 CPU clock periods. This is equivalent to 12 oscillator clock period 27 4109J–8051–10/06 in standard mode or 6 oscillator clock periods in X2 mode. For further information on X2 mode, refer to the Section “X2 Feature”, page 12. Slow peripherals can be accessed by stretching the read and write cycles. This is done using the M0 bit in AUXR register. Setting this bit changes the width of the RD and WR signals from 3 to 15 CPU clock periods. For simplicity, Figure 11 and Figure 12 depict the bus cycle waveforms in idealized form and do not provide precise timing information. For bus cycle timing parameters refer to the Section “AC Characteristics”. Figure 11. External Data Read Waveforms CPU Clock ALE RD(1) P0 P2 Notes: DPL or Ri D7:0 DPH or P2(2),(3) P2 1. RD signal may be stretched using M0 bit in AUXR register. 2. When executing MOVX @Ri instruction, P2 outputs SFR content. 3. When executing MOVX @DPTR instruction, if DPHDIS is set (Page Access Mode), P2 outputs SFR content instead of DPH. Figure 12. External Data Write Waveforms CPU Clock ALE WR(1) P0 P2 Notes: 6.3 6.3.1 DPL or Ri P2 D7:0 DPH or P2(2),(3) 1. WR signal may be stretched using M0 bit in AUXR register. 2. When executing MOVX @Ri instruction, P2 outputs SFR content. 3. When executing MOVX @DPTR instruction, if DPHDIS is set (Page Access Mode), P2 outputs SFR content instead of DPH. Dual Data Pointer Description The AT8xC51SND1C implement a second data pointer for speeding up code execution and reducing code size in case of intensive usage of external memory accesses. 28 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C DPTR0 and DPTR1 are seen by the CPU as DPTR and are accessed using the SFR addresses 83h and 84h that are the DPH and DPL addresses. The DPS bit in AUXR1 register (see Table 22) is used to select whether DPTR is the data pointer 0 or the data pointer 1 (see Figure 13). Figure 13. Dual Data Pointer Implementation DPL0 0 DPL1 1 DPL DPTR0 DPS DPTR1 DPH0 0 DPH1 1 AUXR1.0 DPTR DPH 6.3.2 Application Software can take advantage of the additional data pointers to both increase speed and reduce code size, for example, block operations (copy, compare, search …) are well served by using one data pointer as a “source” pointer and the other one as a “destination” pointer. Below is an example of block move implementation using the 2 pointers and coded in assembler. The latest C compiler also takes advantage of this feature by providing enhanced algorithm libraries. The INC instruction is a short (2 Bytes) and fast (6 CPU clocks) way to manipulate the DPS bit in the AUXR1 register. However, note that the INC instruction does not directly force the DPS bit to a particular state, but simply toggles it. In simple routines, such as the block move example, only the fact that DPS is toggled in the proper sequence matters, not its actual value. In other words, the block move routine works the same whether DPS is '0' or '1' on entry. ; ; ; ; ASCII block move using dual data pointers Modifies DPTR0, DPTR1, A and PSW Ends when encountering NULL character Note: DPS exits opposite of entry state unless an extra INC AUXR1 is added AUXR1 move: EQU mov inc mov mv_loop: inc movx inc inc movx inc jnz end_move: 0A2h DPTR,#SOURCE AUXR1 DPTR,#DEST AUXR1 A,@DPTR DPTR AUXR1 @DPTR,A DPTR mv_loop ; ; ; ; ; ; ; ; ; ; address of SOURCE switch data pointers address of DEST switch data pointers get a Byte from SOURCE increment SOURCE address switch data pointers write the Byte to DEST increment DEST address check for NULL terminator 29 4109J–8051–10/06 6.4 Registers Table 18. PSW Register PSW (S:8Eh) – Program Status Word Register 7 6 5 4 3 2 1 0 CY AC F0 RS1 RS0 OV F1 P Bit Number Bit Mnemonic Description 7 CY Carry Flag Carry out from bit 1 of ALU operands. 6 AC Auxiliary Carry Flag Carry out from bit 1 of addition operands. 5 F0 User Definable Flag 0 4-3 RS1:0 Register Bank Select Bits Refer to Table 15 for bits description. 2 OV Overflow Flag Overflow set by arithmetic operations. 1 F1 User Definable Flag 1 0 P Parity Bit Set when ACC contains an odd number of 1’s. Cleared when ACC contains an even number of 1’s. Reset Value = 0000 0000b Table 19. AUXR Register AUXR (S:8Eh) – Auxiliary Control Register 7 6 5 4 3 2 1 0 - EXT16 M0 DPHDIS XRS1 XRS0 EXTRAM AO Bit Number 7 30 Bit Mnemonic Description - Reserved The value read from this bit is indeterminate. Do not set this bit. External 16-bit Access Enable Bit Set to enable 16-bit access mode during MOVX instructions. Clear to disable 16-bit access mode and enable standard 8-bit access mode during MOVX instructions. 6 EXT16 5 M0 External Memory Access Stretch Bit Set to stretch RD or WR signals duration to 15 CPU clock periods. Clear not to stretch RD or WR signals and set duration to 3 CPU clock periods. 4 DPHDIS DPH Disable Bit Set to disable DPH output on P2 when executing MOVX @DPTR instruction. Clear to enable DPH output on P2 when executing MOVX @DPTR instruction. 3-2 XRS1:0 Expanded RAM Size Bits Refer to Table 16 for ERAM size description. AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Bit Number Bit Mnemonic Description 1 EXTRAM 0 AO External RAM Enable Bit Set to select the external XRAM when executing MOVX @Ri or MOVX @DPTR instructions. Clear to select the internal expanded RAM when executing MOVX @Ri or MOVX @DPTR instructions. ALE Output Enable Bit Set to output the ALE signal only during MOVX instructions. Clear to output the ALE signal at a constant rate of FCPU/3. Reset Value = X000 1101b 31 4109J–8051–10/06 7. Special Function Registers The Special Function Registers (SFRs) of the AT8xC51SND1C derivatives fall into the categories detailed in Table 20 to Table 36. The relative addresses of these SFRs are provided together with their reset values in Table 37. In this table, the bit-addressable registers are identified by Note 1. Table 20. C51 Core SFRs Mnemonic Add Name ACC E0h Accumulator B F0h B Register PSW D0h Program Status Word SP 81h Stack Pointer DPL 82h Data Pointer Low Byte DPH 83h Data Pointer High Byte 7 6 5 4 3 2 1 0 CY AC F0 RS1 RS0 OV F1 P 7 6 5 4 3 2 1 0 SMOD1 SMOD0 - - GF1 GF0 PD IDL M0 DPHDIS XRS1 XRS0 EXTRAM AO 1) - GF3 0 - DPS NV5 NV4 NV3 NV2 NV1 NV0 Table 21. System Management SFRs Mnemonic Add Name PCON 87h Power Control AUXR 8Eh Auxiliary Register 0 - EXT16 AUXR1 A2h Auxiliary Register 1 - - NVERS FBh Version Number NV7 NV6 Note: ENBOOT( 1. ENBOOT bit is only available in AT89C51SND1C product. Table 22. PLL and System Clock SFRs Mnemonic Add Name 7 6 5 4 3 2 1 0 CKCON 8Fh Clock Control - - - - - - - X2 PLLCON E9h PLL Control R1 R0 - - PLLRES - PLLEN PLOCK PLLNDIV EEh PLL N Divider - N6 N5 N4 N3 N2 N1 N0 PLLRDIV EFh PLL R Divider R9 R8 R7 R6 R5 R4 R3 R2 7 6 5 4 3 2 1 0 Table 23. Interrupt SFRs Mnemonic Add Name IEN0 A8h Interrupt Enable Control 0 EA EAUD EMP3 ES ET1 EX1 ET0 EX0 IEN1 B1h Interrupt Enable Control 1 - EUSB - EKB EADC ESPI EI2C EMMC IPH0 B7h Interrupt Priority Control High 0 - IPHAUD IPHMP3 IPHS IPHT1 IPHX1 IPHT0 IPHX0 IPL0 B8h Interrupt Priority Control Low 0 - IPLAUD IPLMP3 IPLS IPLT1 IPLX1 IPLT0 IPLX0 IPH1 B3h Interrupt Priority Control High 1 - IPHUSB - IPHKB IPHADC IPHSPI IPHI2C IPHMMC 32 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Table 23. Interrupt SFRs (Continued) Mnemonic Add Name 7 6 5 4 3 2 1 0 IPL1 B2h Interrupt Priority Control Low 1 - IPLUSB - IPLKB IPLADC IPLSPI IPLI2C IPLMMC 7 6 5 4 3 2 1 0 - - - - 7 6 5 4 3 2 1 0 FPL3 FPL2 FPL1 FPL0 FPS FMOD1 FMOD0 FBUSY Table 24. Port SFRs Mnemonic Add Name P0 80h 8-bit Port 0 P1 90h 8-bit Port 1 P2 A0h 8-bit Port 2 P3 B0h 8-bit Port 3 P4 C0h 8-bit Port 4 P5 D8h 4-bit Port 5 Table 25. Flash Memory SFR Mnemonic FCON (1) Note: Add Name D1h Flash Control 1. FCON register is only available in AT89C51SND1C product. Table 26. Timer SFRs Mnemonic Add Name 7 6 5 4 3 2 1 0 TCON 88h Timer/Counter 0 and 1 Control TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0 TMOD 89h Timer/Counter 0 and 1 Modes GATE1 C/T1# M11 M01 GATE0 C/T0# M10 M00 TL0 8Ah Timer/Counter 0 Low Byte TH0 8Ch Timer/Counter 0 High Byte TL1 8Bh Timer/Counter 1 Low Byte TH1 8Dh Timer/Counter 1 High Byte WDTRST A6h Watchdog Timer Reset WDTPRG A7h Watchdog Timer Program - - - - - WTO2 WTO1 WTO0 7 6 5 4 3 2 1 0 Table 27. MP3 Decoder SFRs Mnemonic Add Name MP3CON AAh MP3 Control MPEN MPBBST CRCEN MSKANC MSKREQ MSKLAY MSKSYN MSKCRC MP3STA C8h MP3 Status MPANC MPREQ ERRLAY ERRSYN ERRCRC MPFS1 MPFS0 MPVER MP3STA1 AFh MP3 Status 1 - - - MPFREQ MPBREQ - - - 33 4109J–8051–10/06 Table 27. MP3 Decoder SFRs (Continued) Mnemonic Add Name 7 6 5 4 3 2 1 0 MP3DAT ACh MP3 Data MPD7 MPD6 MPD5 MPD4 MPD3 MPD2 MPD1 MPD0 MP3ANC ADh MP3 Ancillary Data AND7 AND6 AND5 AND4 AND3 AND2 AND1 AND0 MP3VOL 9Eh MP3 Audio Volume Control Left - - - VOL4 VOL3 VOL2 VOL1 VOL0 MP3VOR 9Fh MP3 Audio Volume Control Right - - - VOR4 VOR3 VOR2 VOR1 VOR0 MP3BAS B4h MP3 Audio Bass Control - - - BAS4 BAS3 BAS2 BAS1 BAS0 MP3MED B5h MP3 Audio Medium Control - - - MED4 MED3 MED2 MED1 MED0 MP3TRE B6h MP3 Audio Treble Control - - - TRE4 TRE3 TRE2 TRE1 TRE0 MP3CLK EBh MP3 Clock Divider - - - MPCD4 MPCD3 MPCD2 MPCD1 MPCD0 7 6 5 4 3 2 1 0 Table 28. Audio Interface SFRs Mnemonic Add Name AUDCON0 9Ah Audio Control 0 JUST4 JUST3 JUST2 JUST1 JUST0 POL DSIZ HLR AUDCON1 9Bh Audio Control 1 SRC DRQEN MSREQ MUDRN - DUP1 DUP0 AUDEN AUDSTA 9Ch Audio Status SREQ UDRN AUBUSY - - - - - AUDDAT 9Dh Audio Data AUD7 AUD6 AUD5 AUD4 AUD3 AUD2 AUD1 AUD0 AUDCLK ECh Audio Clock Divider - - - AUCD4 AUCD3 AUCD2 AUCD1 AUCD0 34 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Table 29. USB Controller SFRs Mnemonic Add Name 7 6 5 4 3 2 1 0 USBCON BCh USB Global Control USBE SUSPCL K SDRMWU P - UPRSM RMWUPE CONFG FADDEN USBADDR C6h USB Address FEN UADD6 UADD5 UADD4 UADD3 UADD2 UADD1 UADD0 USBINT BDh USB Global Interrupt - - WUPCPU EORINT SOFINT - - SPINT USBIEN BEh USB Global Interrupt Enable - - EWUPCP EEORINT U ESOFINT - - ESPINT UEPNUM C7h USB Endpoint Number - - - - - - EPNUM1 EPNUM0 UEPCONX D4h USB Endpoint X Control EPEN NAKIEN NAKOUT NAKIN DTGL EPDIR UEPSTAX CEh USB Endpoint X Status DIR RXOUTB 1 STALLRQ TXRDY STLCRC RXSETU P RXOUTB 0 TXCMP UEPRST D5h USB Endpoint Reset - - - - - EP2RST EP1RST EP0RST UEPINT F8h USB Endpoint Interrupt - - - - - EP2INT EP1INT EP0INT UEPIEN C2h USB Endpoint Interrupt Enable - - - - - EP2INTE EP1INTE EP0INTE UEPDATX CFh USB Endpoint X FIFO Data FDAT7 FDAT6 FDAT5 FDAT4 FDAT3 FDAT2 FDAT1 FDAT0 UBYCTX E2h USB Endpoint X Byte Counter - BYCT6 BYCT5 BYCT4 BYCT3 BYCT2 BYCT1 BYCT0 UFNUML BAh USB Frame Number Low FNUM7 FNUM6 FNUM5 FNUM4 FNUM3 FNUM2 FNUM1 FNUM0 UFNUMH BBh USB Frame Number High - - CRCOK CRCERR - FNUM10 FNUM9 FNUM8 USBCLK EAh USB Clock Divider - - - - - - USBCD1 USBCD0 7 6 5 4 3 2 1 0 EPTYPE1 EPTYPE0 Table 30. MMC Controller SFRs Mnemonic Add Name MMCON0 E4h MMC Control 0 DRPTR DTPTR CRPTR CTPTR MBLOCK DFMT RFMT CRCDIS MMCON1 E5h MMC Control 1 BLEN3 BLEN2 BLEN1 BLEN0 DATDIR DATEN RESPEN CMDEN MMCON2 E6h MMC Control 2 MMCEN DCR CCR - - DATD1 DATD0 FLOWC MMSTA DEh MMC Control and Status - - CBUSY CRC16S DATFS CRC7S RESPFS CFLCK MMINT E7h MMC Interrupt MCBI EORI EOCI EOFI F2FI F1FI F2EI F1EI MMMSK DFh MMC Interrupt Mask MCBM EORM EOCM EOFM F2FM F1FM F2EM F1EM MMCMD DDh MMC Command MC7 MC6 MC5 MC4 MC3 MC2 MC1 MC0 MMDAT DCh MMC Data MD7 MD6 MD5 MD4 MD3 MD2 MD1 MD0 MMCLK EDh MMC Clock Divider MMCD7 MMCD6 MMCD5 MMCD4 MMCD3 MMCD2 MMCD1 MMCD0 7 6 5 4 3 2 1 0 D15 D14 D13 D12 D11 D10 D9 D8 Table 31. IDE Interface SFR Mnemonic Add Name DAT16H F9h High Order Data Byte 35 4109J–8051–10/06 Table 32. Serial I/O Port SFRs Mnemonic Add Name SCON 98h Serial Control SBUF 99h Serial Data Buffer SADEN B9h Slave Address Mask SADDR A9h Slave Address BDRCON 92h Baud Rate Control BRL 91h Baud Rate Reload 7 6 5 4 3 2 1 0 FE/SM0 SM1 SM2 REN TB8 RB8 TI RI BRR TBCK RBCK SPD SRC Table 33. SPI Controller SFRs Mnemonic Add Name 7 6 5 4 3 2 1 0 SPCON C3h SPI Control SPR2 SPEN SSDIS MSTR CPOL CPHA SPR1 SPR0 SPSTA C4h SPI Status SPIF WCOL - MODF - - - - SPDAT C5h SPI Data SPD7 SPD6 SPD5 SPD4 SPD3 SPD2 SPD1 SPD0 7 6 5 4 3 2 1 0 Table 34. Two Wire Controller SFRs Mnemonic Add Name SSCON 93h Synchronous Serial Control SSCR2 SSPE SSSTA SSSTO SSI SSAA SSCR1 SSCR0 SSSTA 94h Synchronous Serial Status SSC4 SSC3 SSC2 SSC1 SSC0 0 0 0 SSDAT 95h Synchronous Serial Data SSD7 SSD6 SSD5 SSD4 SSD3 SSD2 SSD1 SSD0 SSADR 96h Synchronous Serial Address SSA7 SSA6 SSA5 SSA4 SSA3 SSA2 SSA1 SSGC 7 6 5 4 3 2 1 0 Table 35. Keyboard Interface SFRs Mnemonic Add Name KBCON A3h Keyboard Control KINL3 KINL2 KINL1 KINL0 KINM3 KINM2 KINM1 KINM0 KBSTA A4h Keyboard Status KPDE - - - KINF3 KINF2 KINF1 KINF0 Table 36. A/D Controller SFRs Mnemonic Add Name 7 6 5 4 3 2 1 0 ADCON F3h ADC Control - ADIDL ADEN ADEOC ADSST - - ADCS ADCLK F2h ADC Clock Divider - - - ADCD4 ADCD3 ADCD2 ADCD1 ADCD0 ADDL F4h ADC Data Low Byte - - - - - - ADAT1 ADAT0 ADDH F5h ADC Data High Byte ADAT9 ADAT8 ADAT7 ADAT6 ADAT5 ADAT4 ADAT3 ADAT2 36 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Table 37. SFR Addresses and Reset Values 0/8 1/9 F8h UEPINT 0000 0000 DAT16H XXXX XXXX F0h B(1) 0000 0000 PLLCON 0000 1000 E8h ACC(1) E0h P5(1) XXXX 1111 D0h PSW(1) 0000 0000 C8h MP3STA(1) 0000 0001 C0h P4(1) 1111 1111 B8h IPL0(1) X000 0000 B0h 3/B 4/C 5/D 6/E FFh ADCLK 0000 0000 ADCON 0000 0000 ADDL 0000 0000 ADDH 0000 0000 USBCLK 0000 0000 MP3CLK 0000 0000 AUDCLK 0000 0000 MMCLK 0000 0000 PLLNDIV 0000 0000 PLLRDIV 0000 0000 EFh MMCON0 0000 0000 MMCON1 0000 0000 MMCON2 0000 0000 MMINT 0000 0011 E7h MMDAT 1111 1111 MMCMD 1111 1111 MMSTA 0000 0000 MMMSK 1111 1111 DFh UEPCONX 1000 0000 UEPRST 0000 0000 FCON(3) 1111 0000(4) F7h D7h UEPSTAX 0000 0000 UEPDATX XXXX XXXX CFh UEPNUM 0000 0000 C7h UEPIEN 0000 0000 SPCON 0001 0100 SPSTA 0000 0000 SPDAT XXXX XXXX USBADDR 0000 0000 SADEN 0000 0000 UFNUML 0000 0000 UFNUMH 0000 0000 USBCON 0000 0000 USBINT 0000 0000 USBIEN 0001 0000 P3(1) 1111 1111 IEN1 0000 0000 IPL1 0000 0000 IPH1 0000 0000 MP3BAS 0000 0000 MP3MED 0000 0000 MP3TRE 0000 0000 A8h IEN0(1) 0000 0000 SADDR 0000 0000 MP3CON 0011 1111 MP3DAT 0000 0000 MP3ANC 0000 0000 A0h P2(1) 1111 1111 98h SCON 0000 0000 90h 88h 80h 7/F NVERS XXXX XXXX(2) UBYCTLX 0000 0000 0000 0000 D8h 2/A IPH0 X000 0000 B7h MP3STA1 0100 0001 AFh WDTRST XXX XXXX WDTPRG XXXX X000 A7h MP3VOR 0000 0000 9Fh AUXR1 XXXX 00X0 KBCON 0000 1111 KBSTA 0000 0000 SBUF XXXX XXXX AUDCON0 0000 1000 AUDCON1 1011 0010 AUDSTA 1100 0000 AUDDAT 1111 1111 MP3VOL 0000 0000 P1(1) 1111 1111 BRL 0000 0000 BDRCON XXX0 0000 SSCON 0000 0000 SSSTA 1111 1000 SSDAT 1111 1111 SSADR 1111 1110 TCON(1) 0000 0000 TMOD 0000 0000 TL0 0000 0000 TL1 0000 0000 TH0 0000 0000 TH1 0000 0000 AUXR X000 1101 P0(1) 1111 1111 SP 0000 0111 DPL 0000 0000 DPH 0000 0000 0/8 1/9 2/A 3/B 4/C 5/D BFh 6/E 97h CKCON 0000 000X(5) 8Fh PCON 00XX 0000 87h 7/F Reserved Notes: 1. SFR registers with least significant nibble address equal to 0 or 8 are bit-addressable. 2. NVERS reset value depends on the silicon version: 1000 0100 for AT89C51SND1C product and 0000 0001 for AT83SND1C product. 3. FCON register is only available in AT89C51SND1C product. 4. FCON reset value is 00h in case of reset with hardware condition. 5. CKCON reset value depends on the X2B bit (programmed or unprogrammed) in the Hardware Byte. 37 4109J–8051–10/06 8. Interrupt System The AT8xC51SND1C, like other control-oriented computer architectures, employ a program interrupt method. This operation branches to a subroutine and performs some service in response to the interrupt. When the subroutine completes, execution resumes at the point where the interrupt occurred. Interrupts may occur as a result of internal AT8xC51SND1C activity (e.g., timer overflow) or at the initiation of electrical signals external to the microcontroller (e.g., keyboard). In all cases, interrupt operation is programmed by the system designer, who determines priority of interrupt service relative to normal code execution and other interrupt service routines. All of the interrupt sources are enabled or disabled by the system designer and may be manipulated dynamically. A typical interrupt event chain occurs as follows: • An internal or external device initiates an interrupt-request signal. The AT8xC51SND1C, latches this event into a flag buffer. • The priority of the flag is compared to the priority of other interrupts by the interrupt handler. A high priority causes the handler to set an interrupt flag. • This signals the instruction execution unit to execute a context switch. This context switch breaks the current flow of instruction sequences. The execution unit completes the current instruction prior to a save of the program counter (PC) and reloads the PC with the start address of a software service routine. • The software service routine executes assigned tasks and as a final activity performs a RETI (return from interrupt) instruction. This instruction signals completion of the interrupt, resets the interrupt-in-progress priority and reloads the program counter. Program operation then continues from the original point of interruption. Table 38. Interrupt System Signals Signal Name Type INT0 I External Interrupt 0 See section "External Interrupts", page 41. P3.2 INT1 I External Interrupt 1 See section “External Interrupts”, page 41. P3.3 KIN3:0 I Keyboard Interrupt Inputs See section “Keyboard Interface”, page 178. Description Alternate Function P1.3:0 Six interrupt registers are used to control the interrupt system. 2 8-bit registers are used to enable separately the interrupt sources: IEN0 and IEN1 registers (see Table 41 and Table 42). Four 8-bit registers are used to establish the priority level of the different sources: IPH0, IPL0, IPH1 and IPL1 registers (see Table 43 to Table 46). 8.1 Interrupt System Priorities Each of the interrupt sources on the AT8xC51SND1C can be individually programmed to one of four priority levels. This is accomplished by one bit in the Interrupt Priority High registers (IPH0 and IPH1) and one bit in the Interrupt Priority Low registers (IPL0 and IPL1). This provides each interrupt source four possible priority levels according to Table 39. 38 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Table 39. Priority Levels IPHxx IPLxx Priority Level 0 0 0 Lowest 0 1 1 1 0 2 1 1 3 Highest A low-priority interrupt is always interrupted by a higher priority interrupt but not by another interrupt of lower or equal priority. Higher priority interrupts are serviced before lower priority interrupts. The response to simultaneous occurrence of equal priority interrupts is determined by an internal hardware polling sequence detailed in Table 40. Thus, within each priority level there is a second priority structure determined by the polling sequence. The interrupt control system is shown in Figure 8-1. Table 40. Priority within Same Level Priority Number Interrupt Address Vectors Interrupt Request Flag Cleared by Hardware (H) or by Software (S) 0 (Highest Priority) C:0003h H if edge, S if level Timer 0 1 C:000Bh H INT1 2 C:0013h H if edge, S if level Timer 1 3 C:001Bh H Serial Port 4 C:0023h S MP3 Decoder 5 C:002Bh S Audio Interface 6 C:0033h S MMC Interface 7 C:003Bh S Two Wire Controller 8 C:0043h S SPI Controller 9 C:004Bh S A to D Converter 10 C:0053h S Keyboard 11 C:005Bh S Reserved 12 C:0063h - USB 13 C:006Bh S 14 (Lowest Priority) C:0073h - Interrupt Name INT0 Reserved 39 4109J–8051–10/06 Figure 8-1. Interrupt Control System INT0 00 01 10 11 External Interrupt 0 Highest Priority Interrupts EX0 00 01 10 11 IEN0.0 Timer 0 ET0 00 01 10 11 IEN0.1 INT1 External Interrupt 1 EX1 00 01 10 11 IEN0.2 Timer 1 ET1 TXD RXD 00 01 10 11 IEN0.3 Serial Port ES 00 01 10 11 IEN0.4 MP3 Decoder EMP3 Audio Interface 00 01 10 11 IEN0.5 EAUD MCLK MDAT MCMD MMC Controller 00 01 10 11 IEN0.6 EMMC SCL SDA TWI Controller 00 01 10 11 IEN1.0 EI2C SCK SI SO SPI Controller 00 01 10 11 IEN1.1 ESPI AIN1:0 A to D Converter 00 01 10 11 IEN1.2 EADC 00 01 10 11 IEN1.3 KIN3:0 Keyboard EKB D+ D- USB Controller 00 01 10 11 IEN1.4 EUSB EA IEN1.6 IEN0.7 Interrupt Enable 40 IPH/L Priority Enable Lowest Priority Interrupts AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 8.2 8.2.1 External Interrupts INT1:0 Inputs External interrupts INT0 and INT1 (INTn, n = 0 or 1) pins may each be programmed to be leveltriggered or edge-triggered, dependent upon bits IT0 and IT1 (ITn, n = 0 or 1) in TCON register as shown in Figure 8-2. If ITn = 0, INTn is triggered by a low level at the pin. If ITn = 1, INTn is negative-edge triggered. External interrupts are enabled with bits EX0 and EX1 (EXn, n = 0 or 1) in IEN0. Events on INTn set the interrupt request flag IEn in TCON register. If the interrupt is edge-triggered, the request flag is cleared by hardware when vectoring to the interrupt service routine. If the interrupt is level-triggered, the interrupt service routine must clear the request flag and the interrupt must be deasserted before the end of the interrupt service routine. INT0 and INT1 inputs provide both the capability to exit from Power-down mode on low level signals as detailed in section “Exiting Power-down Mode”, page 50. Figure 8-2. INT1:0 Input Circuitry INT0/1 INT0/1 Interrupt Request 0 IE0/1 1 TCON.1/3 EX0/1 IEN0.0/2 IT0/1 TCON.0/2 8.2.2 KIN3:0 Inputs External interrupts KIN0 to KIN3 provide the capability to connect a matrix keyboard. For detailed information on these inputs, refer to section “Keyboard Interface”, page 178. 8.2.3 Input Sampling External interrupt pins (INT1:0 and KIN3:0) are sampled once per peripheral cycle (6 peripheral clock periods) (see Figure 8-3). A level-triggered interrupt pin held low or high for more than 6 peripheral clock periods (12 oscillator in standard mode or 6 oscillator clock periods in X2 mode) guarantees detection. Edge-triggered external interrupts must hold the request pin low for at least 6 peripheral clock periods. Figure 8-3. Minimum Pulse Timings Level-Triggered Interrupt > 1 Peripheral Cycle 1 cycle Edge-Triggered Interrupt > 1 Peripheral Cycle 1 cycle 1 cycle 41 4109J–8051–10/06 8.3 Registers Table 41. IEN0 Register IEN0 (S:A8h) – Interrupt Enable Register 0 7 6 5 4 3 2 1 0 EA EAUD EMP3 ES ET1 EX1 ET0 EX0 Bit Number 7 Bit Mnemonic Description EA Enable All Interrupt Bit Set to enable all interrupts. Clear to disable all interrupts. If EA = 1, each interrupt source is individually enabled or disabled by setting or clearing its interrupt enable bit. 6 EAUD Audio Interface Interrupt Enable Bit Set to enable audio interface interrupt. Clear to disable audio interface interrupt. 5 EMP3 MP3 Decoder Interrupt Enable Bit Set to enable MP3 decoder interrupt. Clear to disable MP3 decoder interrupt. 4 ES Serial Port Interrupt Enable Bit Set to enable serial port interrupt. Clear to disable serial port interrupt. 3 ET1 Timer 1 Overflow Interrupt Enable Bit Set to enable timer 1 overflow interrupt. Clear to disable timer 1 overflow interrupt. 2 EX1 External Interrupt 1 Enable bit Set to enable external interrupt 1. Clear to disable external interrupt 1. 1 ET0 Timer 0 Overflow Interrupt Enable Bit Set to enable timer 0 overflow interrupt. Clear to disable timer 0 overflow interrupt. 0 EX0 External Interrupt 0 Enable Bit Set to enable external interrupt 0. Clear to disable external interrupt 0. Reset Value = 0000 0000b 8.3.0.1 Table 42. IEN1 Register IEN1 (S:B1h) – Interrupt Enable Register 1 42 7 6 5 4 3 2 1 0 - EUSB - EKB EADC ESPI EI2C EMMC AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Bit Number Bit Mnemonic Description Reserved The value read from this bit is always 0. Do not set this bit. 7 - 6 EUSB 5 - 4 EKB 3 EADC A to D Converter Interrupt Enable Bit Set to enable ADC interrupt. Clear to disable ADC interrupt. 2 ESPI SPI Controller Interrupt Enable Bit Set to enable SPI interrupt. Clear to disable SPI interrupt. 1 EI2C Two Wire Controller Interrupt Enable Bit Set to enable Two Wire interrupt. Clear to disable Two Wire interrupt. 0 EMMC USB Interface Interrupt Enable Bit Set this bit to enable USB interrupts. Clear this bit to disable USB interrupts. Reserved The value read from this bit is always 0. Do not set this bit. Keyboard Interface Interrupt Enable Bit Set to enable Keyboard interrupt. Clear to disable Keyboard interrupt. MMC Interface Interrupt Enable Bit Set to enable MMC interrupt. Clear to disable MMC interrupt. Reset Value = 0000 0000b 8.3.0.2 Table 43. IPH0 Register IPH0 (S:B7h) – Interrupt Priority High Register 0 7 6 5 4 3 2 1 0 - IPHAUD IPHMP3 IPHS IPHT1 IPHX1 IPHT0 IPHX0 43 4109J–8051–10/06 Bit Number Bit Mnemonic Description Reserved The value read from this bit is indeterminate. Do not set this bit. 7 - 6 IPHAUD Audio Interface Interrupt Priority Level MSB Refer to Table 39 for priority level description. 5 IPHMP3 MP3 Decoder Interrupt Priority Level MSB Refer to Table 39 for priority level description. 4 IPHS Serial Port Interrupt Priority Level MSB Refer to Table 39 for priority level description. 3 IPHT1 Timer 1 Interrupt Priority Level MSB Refer to Table 39 for priority level description. 2 IPHX1 External Interrupt 1 Priority Level MSB Refer to Table 39 for priority level description. 1 IPHT0 Timer 0 Interrupt Priority Level MSB Refer to Table 39 for priority level description. 0 IPHX0 External Interrupt 0 Priority Level MSB Refer to Table 39 for priority level description. Reset Value = X000 0000b Table 44. IPH1 Register IPH1 (S:B3h) – Interrupt Priority High Register 1 7 6 5 4 3 2 1 0 - IPHUSB - IPHKB IPHADC IPHSPI IPHI2C IPHMMC Bit Number Bit Mnemonic Description Reserved The value read from this bit is always 0. Do not set this bit. 7 - 6 IPHUSB 5 - 4 IPHKB 3 IPHADC A to D Converter Interrupt Priority Level MSB Refer to Table 39 for priority level description. 2 IPHSPI SPI Interrupt Priority Level MSB Refer to Table 39 for priority level description. 1 IPHI2C Two Wire Controller Interrupt Priority Level MSB Refer to Table 39 for priority level description. 0 IPHMMC USB Interrupt Priority Level MSB Refer to Table 39 for priority level description. Reserved The value read from this bit is always 0. Do not set this bit. Keyboard Interrupt Priority Level MSB Refer to Table 39 for priority level description. MMC Interrupt Priority Level MSB Refer to Table 39 for priority level description. Reset Value = 0000 0000b 44 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Table 45. IPL0 Register IPL0 (S:B8h) - Interrupt Priority Low Register 0 7 6 5 4 3 2 1 0 - IPLAUD IPLMP3 IPLS IPLT1 IPLX1 IPLT0 IPLX0 Bit Number Bit Mnemonic Description Reserved The value read from this bit is indeterminate. Do not set this bit. 7 - 6 IPLAUD Audio Interface Interrupt Priority Level LSB Refer to Table 39 for priority level description. 5 IPLMP3 MP3 Decoder Interrupt Priority Level LSB Refer to Table 39 for priority level description. 4 IPLS Serial Port Interrupt Priority Level LSB Refer to Table 39 for priority level description. 3 IPLT1 Timer 1 Interrupt Priority Level LSB Refer to Table 39 for priority level description. 2 IPLX1 External Interrupt 1 Priority Level LSB Refer to Table 39 for priority level description. 1 IPLT0 Timer 0 Interrupt Priority Level LSB Refer to Table 39 for priority level description. 0 IPLX0 External Interrupt 0 Priority Level LSB Refer to Table 39 for priority level description. Reset Value = X000 0000b 8.3.0.3 Table 46. IPL1 Register IPL1 (S:B2h) – Interrupt Priority Low Register 1 7 6 5 4 3 2 1 0 - IPLUSB - IPLKB IPLADC IPLSPI IPLI2C IPLMMC 45 4109J–8051–10/06 Bit Number Bit Mnemonic Description Reserved The value read from this bit is always 0. Do not set this bit. 7 - 6 IPLUSB 5 - 4 IPLKB 3 IPLADC A to D Converter Interrupt Priority Level LSB Refer to Table 39 for priority level description. 2 IPLSPI SPI Interrupt Priority Level LSB Refer to Table 39 for priority level description. 1 IPLI2C Two Wire Controller Interrupt Priority Level LSB Refer to Table 39 for priority level description. 0 IPLMMC USB Interrupt Priority Level LSB Refer to Table 39 for priority level description. Reserved The value read from this bit is always 0. Do not set this bit. Keyboard Interrupt Priority Level LSB Refer to Table 39 for priority level description. MMC Interrupt Priority Level LSB Refer to Table 39 for priority level description. Reset Value = 0000 0000b 46 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 9. Power Management 2 power reduction modes are implemented in the AT8xC51SND1C: the Idle mode and the Power-down mode. These modes are detailed in the following sections. In addition to these power reduction modes, the clocks of the core and peripherals can be dynamically divided by 2 using the X2 mode detailed in section “X2 Feature”, page 12. 9.1 Reset In order to start-up (cold reset) or to restart (warm reset) properly the microcontroller, an high level has to be applied on the RST pin. A bad level leads to a wrong initialization of the internal registers like SFRs, Program Counter… and to unpredictable behavior of the microcontroller. A proper device reset initializes the AT8xC51SND1C and vectors the CPU to address 0000h. RST input has a pull-down resistor allowing power-on reset by simply connecting an external capacitor to VDD as shown in Figure 9-1. A warm reset can be applied either directly on the RST pin or indirectly by an internal reset source such as the watchdog timer. Resistor value and input characteristics are discussed in the Section “DC Characteristics” of the AT8xC51SND1C datasheet. The status of the Port pins during reset is detailed in Table 47. Figure 9-1. Reset Circuitry and Power-On Reset From Internal Reset Source VDD P VDD To CPU Core and Peripherals + RRST RST RST VSS RST input circuitry Power-on Reset Table 47. Pin Conditions in Special Operating Modes Mode Port 0 Port 1 Port 2 Port 3 Port 4 Port 5 MMC Audio Floating High High High High High Floating 1 Idle Data Data Data Data Data Data Data Data Power-down Data Data Data Data Data Data Data Data Reset Note: 9.1.1 1. Refer to section “Audio Output Interface”, page 73. Cold Reset 2 conditions are required before enabling a CPU start-up: • VDD must reach the specified VDD range • The level on X1 input pin must be outside the specification (VIH, VIL) If one of these 2 conditions are not met, the microcontroller does not start correctly and can execute an instruction fetch from anywhere in the program space. An active level applied on the RST pin must be maintained till both of the above conditions are met. A reset is active when the level VIH1 is reached and when the pulse width covers the period of time where VDD and the oscillator are not stabilized. 2 parameters have to be taken into account to determine the reset pulse width: • VDD rise time, • Oscillator startup time. 47 4109J–8051–10/06 To determine the capacitor value to implement, the highest value of these 2 parameters has to be chosen. Table 48 gives some capacitor values examples for a minimum RRST of 50 KΩ and different oscillator startup and VDD rise times. Table 48. Minimum Reset Capacitor Value for a 50 kΩ Pull-down Resistor(1) 1 ms 10 ms 100 ms 5 ms 820 nF 1.2 µF 12 µF 20 ms 2.7 µF 3.9 µF 12 µF Note: 9.1.2 VDD Rise Time Oscillator Start-Up Time 1. These values assume VDD starts from 0V to the nominal value. If the time between 2 on/off sequences is too fast, the power-supply de-coupling capacitors may not be fully discharged, leading to a bad reset sequence. Warm Reset To achieve a valid reset, the reset signal must be maintained for at least 2 machine cycles (24 oscillator clock periods) while the oscillator is running. The number of clock periods is mode independent (X2 or X1). 9.1.3 Watchdog Reset As detailed in section “Watchdog Timer”, page 60, the WDT generates a 96-clock period pulse on the RST pin. In order to properly propagate this pulse to the rest of the application in case of external capacitor or power-supply supervisor circuit, a 1 kΩ resistor must be added as shown in Figure 9-2. Figure 9-2. Reset Circuitry for WDT Reset-out Usage VDD VDD + RST RST VSS 9.2 1K To CPU Core and Peripherals RRST VDD P From WDT Reset Source VSS To Other On-board Circuitry Reset Recommendation to Prevent Flash Corruption An example of bad initialization situation may occur in an instance where the bit ENBOOT in AUXR1 register is initialized from the hardware bit BLJB upon reset. Since this bit allows mapping of the bootloader in the code area, a reset failure can be critical. If one wants the ENBOOT cleared in order to unmap the boot from the code area (yet due to a bad reset) the bit ENBOOT in SFRs may be set. If the value of Program Counter is accidently in the range of the boot memory addresses then a Flash access (write or erase) may corrupt the Flash on-chip memory. It is recommended to use an external reset circuitry featuring power supply monitoring to prevent system malfunction during periods of insufficient power supply voltage (power supply failure, power supply switched off). 48 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 9.3 Idle Mode Idle mode is a power reduction mode that reduces the power consumption. In this mode, program execution halts. Idle mode freezes the clock to the CPU at known states while the peripherals continue to be clocked (refer to section “Oscillator”, page 12). The CPU status before entering Idle mode is preserved, i.e., the program counter and program status word register retain their data for the duration of Idle mode. The contents of the SFRs and RAM are also retained. The status of the Port pins during Idle mode is detailed in Table 47. 9.3.1 Entering Idle Mode To enter Idle mode, the user must set the IDL bit in PCON register (see Table 49). The AT8xC51SND1C enters Idle mode upon execution of the instruction that sets IDL bit. The instruction that sets IDL bit is the last instruction executed. Note: 9.3.2 If IDL bit and PD bit are set simultaneously, the AT8xC51SND1C enter Power-down mode. Then it does not go in Idle mode when exiting Power-down mode. Exiting Idle Mode There are 2 ways to exit Idle mode: 1. Generate an enabled interrupt. – Hardware clears IDL bit in PCON register which restores the clock to the CPU. Execution resumes with the interrupt service routine. Upon completion of the interrupt service routine, program execution resumes with the instruction immediately following the instruction that activated Idle mode. The general-purpose flags (GF1 and GF0 in PCON register) may be used to indicate whether an interrupt occurred during normal operation or during Idle mode. When Idle mode is exited by an interrupt, the interrupt service routine may examine GF1 and GF0. 2. Generate a reset. – Note: 9.4 A logic high on the RST pin clears IDL bit in PCON register directly and asynchronously. This restores the clock to the CPU. Program execution momentarily resumes with the instruction immediately following the instruction that activated the Idle mode and may continue for a number of clock cycles before the internal reset algorithm takes control. Reset initializes the AT8xC51SND1C and vectors the CPU to address C:0000h. During the time that execution resumes, the internal RAM cannot be accessed; however, it is possible for the Port pins to be accessed. To avoid unexpected outputs at the Port pins, the instruction immediately following the instruction that activated Idle mode should not write to a Port pin or to the external RAM. Power-down Mode The Power-down mode places the AT8xC51SND1C in a very low power state. Power-down mode stops the oscillator and freezes all clocks at known states (refer to the Section "Oscillator", page 12). The CPU status prior to entering Power-down mode is preserved, i.e., the program counter, program status word register retain their data for the duration of Power-down mode. In addition, the SFRs and RAM contents are preserved. The status of the Port pins during Powerdown mode is detailed in Table 47. Note: VDD may be reduced to as low as VRET during Power-down mode to further reduce power dissipation. Notice, however, that VDD is not reduced until Power-down mode is invoked. 49 4109J–8051–10/06 9.4.1 Entering Power-down Mode To enter Power-down mode, set PD bit in PCON register. The AT8xC51SND1C enters the Power-down mode upon execution of the instruction that sets PD bit. The instruction that sets PD bit is the last instruction executed. 9.4.2 Exiting Power-down Mode If VDD was reduced during the Power-down mode, do not exit Power-down mode until VDD is restored to the normal operating level. There are 2 ways to exit the Power-down mode: 1. Generate an enabled external interrupt. – Note: The AT8xC51SND1C provides capability to exit from Power-down using INT0, INT1, and KIN3:0 inputs. In addition, using KIN input provides high or low level exit capability (see section “Keyboard Interface”, page 178). Hardware clears PD bit in PCON register which starts the oscillator and restores the clocks to the CPU and peripherals. Using INTn input, execution resumes when the input is released (see Figure 9-3) while using KINx input, execution resumes after counting 1024 clock ensuring the oscillator is restarted properly (see Figure 9-4). This behavior is necessary for decoding the key while it is still pressed. In both cases, execution resumes with the interrupt service routine. Upon completion of the interrupt service routine, program execution resumes with the instruction immediately following the instruction that activated Power-down mode. 1. The external interrupt used to exit Power-down mode must be configured as level sensitive (INT0 and INT1) and must be assigned the highest priority. In addition, the duration of the interrupt must be long enough to allow the oscillator to stabilize. The execution will only resume when the interrupt is deasserted. 2. Exit from power-down by external interrupt does not affect the SFRs nor the internal RAM content. Figure 9-3. Power-down Exit Waveform Using INT1:0 INT1:0 OSC Active phase Figure 9-4. Power-down Phase Oscillator Restart Active Phase Power-down Exit Waveform Using KIN3:0 KIN3:01 OSC Active phase Note: Power-down 1024 clock count Active phase 1. KIN3:0 can be high or low-level triggered. 2. Generate a reset. 50 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C – Notes: 9.5 A logic high on the RST pin clears PD bit in PCON register directly and asynchronously. This starts the oscillator and restores the clock to the CPU and peripherals. Program execution momentarily resumes with the instruction immediately following the instruction that activated Power-down mode and may continue for a number of clock cycles before the internal reset algorithm takes control. Reset initializes the AT8xC51SND1C and vectors the CPU to address 0000h. 1. During the time that execution resumes, the internal RAM cannot be accessed; however, it is possible for the Port pins to be accessed. To avoid unexpected outputs at the Port pins, the instruction immediately following the instruction that activated the Power-down mode should not write to a Port pin or to the external RAM. 2. Exit from power-down by reset redefines all the SFRs, but does not affect the internal RAM content. Registers Table 49. PCON Register PCON (S:87h) – Power Configuration Register 7 6 5 4 3 2 1 0 SMOD1 SMOD0 - - GF1 GF0 PD IDL Bit Number Bit Mnemonic Description 7 SMOD1 Serial Port Mode Bit 1 Set to select double baud rate in mode 1,2 or 3. 6 SMOD0 Serial Port Mode Bit 0 Set to select FE bit in SCON register. Clear to select SM0 bit in SCON register. 5-4 - 3 GF1 General-Purpose Flag 1 One use is to indicate whether an interrupt occurred during normal operation or during Idle mode. 2 GF0 General-Purpose Flag 0 One use is to indicate whether an interrupt occurred during normal operation or during Idle mode. 1 PD Power-Down Mode Bit Cleared by hardware when an interrupt or reset occurs. Set to activate the Power-down mode. If IDL and PD are both set, PD takes precedence. 0 IDL Idle Mode Bit Cleared by hardware when an interrupt or reset occurs. Set to activate the Idle mode. If IDL and PD are both set, PD takes precedence. Reserved The value read from these bits is indeterminate. Do not set these bits. Reset Value = 00XX 0000b 51 4109J–8051–10/06 10. Timers/Counters The AT8xC51SND1C implement 2 general-purpose, 16-bit Timers/Counters. They are identified as Timer 0 and Timer 1, and can be independently configured to operate in a variety of modes as a Timer or as an event Counter. When operating as a Timer, the Timer/Counter runs for a programmed length of time, then issues an interrupt request. When operating as a Counter, the Timer/Counter counts negative transitions on an external pin. After a preset number of counts, the Counter issues an interrupt request. The various operating modes of each Timer/Counter are described in the following sections. 10.1 Timer/Counter Operations For instance, a basic operation is Timer registers THx and TLx (x = 0, 1) connected in cascade to form a 16-bit Timer. Setting the run control bit (TRx) in TCON register (see Table 50) turns the Timer on by allowing the selected input to increment TLx. When TLx overflows it increments THx; when THx overflows it sets the Timer overflow flag (TFx) in TCON register. Setting the TRx does not clear the THx and TLx Timer registers. Timer registers can be accessed to obtain the current count or to enter preset values. They can be read at any time but TRx bit must be cleared to preset their values, otherwise, the behavior of the Timer/Counter is unpredictable. The C/Tx# control bit selects Timer operation or Counter operation by selecting the divideddown peripheral clock or external pin Tx as the source for the counted signal. TRx bit must be cleared when changing the mode of operation, otherwise the behavior of the Timer/Counter is unpredictable. For Timer operation (C/Tx# = 0), the Timer register counts the divided-down peripheral clock. The Timer register is incremented once every peripheral cycle (6 peripheral clock periods). The Timer clock rate is FPER/6, i.e., FOSC/12 in standard mode or FOSC/6 in X2 mode. For Counter operation (C/Tx# = 1), the Timer register counts the negative transitions on the Tx external input pin. The external input is sampled every peripheral cycles. When the sample is high in one cycle and low in the next one, the Counter is incremented. Since it takes 2 cycles (12 peripheral clock periods) to recognize a negative transition, the maximum count rate is FPER/12, i.e., FOSC/24 in standard mode or FOSC/12 in X2 mode. There are no restrictions on the duty cycle of the external input signal, but to ensure that a given level is sampled at least once before it changes, it should be held for at least one full peripheral cycle. 10.2 Timer Clock Controller As shown in Figure 10-1, the Timer 0 (FT0) and Timer 1 (FT1) clocks are derived from either the peripheral clock (FPER) or the oscillator clock (FOSC) depending on the T0X2 and T1X2 bits in CKCON register. These clocks are issued from the Clock Controller block as detailed in Section “Clock Controller”, page 12. When T0X2 or T1X2 bit is set, the Timer 0 or Timer 1 clock frequency is fixed and equal to the oscillator clock frequency divided by 2. When cleared, the Timer clock frequency is equal to the oscillator clock frequency divided by 2 in standard mode or to the oscillator clock frequency in X2 mode. 52 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 10-1. Timer 0 and Timer 1 Clock Controller and Symbols PER CLOCK 0 Timer 0 Clock PER CLOCK 0 Timer 1 Clock 1 OSC CLOCK 1 OSC CLOCK ÷2 T0X2 T1X2 CKCON.1 CKCON.2 TIM0 CLOCK TIM1 CLOCK Timer 1 Clock Symbol Timer 0 Clock Symbol 10.3 ÷2 Timer 0 Timer 0 functions as either a Timer or event Counter in four modes of operation. Figure 10-2 through Figure 10-8 show the logical configuration of each mode. Timer 0 is controlled by the four lower bits of TMOD register (see Table 51) and bits 0, 1, 4 and 5 of TCON register (see Table 50). TMOD register selects the method of Timer gating (GATE0), Timer or Counter operation (C/T0#) and mode of operation (M10 and M00). TCON register provides Timer 0 control functions: overflow flag (TF0), run control bit (TR0), interrupt flag (IE0) and interrupt type control bit (IT0). For normal Timer operation (GATE0 = 0), setting TR0 allows TL0 to be incremented by the selected input. Setting GATE0 and TR0 allows external pin INT0 to control Timer operation. Timer 0 overflow (count rolls over from all 1s to all 0s) sets TF0 flag generating an interrupt request. It is important to stop Timer/Counter before changing mode. 10.3.1 Mode 0 (13-bit Timer) Mode 0 configures Timer 0 as a 13-bit Timer which is set up as an 8-bit Timer (TH0 register) with a modulo 32 prescaler implemented with the lower five bits of TL0 register (see Figure 10-2). The upper three bits of TL0 register are indeterminate and should be ignored. Prescaler overflow increments TH0 register. Figure 10-3 gives the overflow period calculation formula. Figure 10-2. Timer/Counter x (x = 0 or 1) in Mode 0 TIMx CLOCK ÷6 0 1 TLx (5 Bits) THx (8 Bits) Overflow TFx TCON reg Timer x Interrupt Request Tx C/Tx# TMOD Reg INTx GATEx TMOD Reg TRx TCON Reg 53 4109J–8051–10/06 Figure 10-3. Mode 0 Overflow Period Formula TFxPER= 10.3.2 6 ⋅ (16384 – (THx, TLx)) FTIMx Mode 1 (16-bit Timer) Mode 1 configures Timer 0 as a 16-bit Timer with TH0 and TL0 registers connected in cascade (see Figure 10-4). The selected input increments TL0 register. Figure 10-5 gives the overflow period calculation formula when in timer mode. Figure 10-4. Timer/Counter x (x = 0 or 1) in Mode 1 TIMx CLOCK ÷6 0 THx (8 bits) 1 TLx (8 bits) Overflow TFx TCON Reg Tx Timer x Interrupt Request C/Tx# TMOD Reg INTx GATEx TRx TMOD Reg TCON Reg Figure 10-5. Mode 1 Overflow Period Formula TFxPER= 10.3.3 6 ⋅ (65536 – (THx, TLx)) FTIMx Mode 2 (8-bit Timer with Auto-Reload) Mode 2 configures Timer 0 as an 8-bit Timer (TL0 register) that automatically reloads from TH0 register (see Table 52). TL0 overflow sets TF0 flag in TCON register and reloads TL0 with the contents of TH0, which is preset by software. When the interrupt request is serviced, hardware clears TF0. The reload leaves TH0 unchanged. The next reload value may be changed at any time by writing it to TH0 register. Figure 10-7 gives the autoreload period calculation formula when in timer mode. Figure 10-6. Timer/Counter x (x = 0 or 1) in Mode 2 TIMx CLOCK ÷6 0 TLx (8 bits) 1 Tx Overflow TFx TCON reg Timer x Interrupt Request C/Tx# TMOD reg INTx GATEx TMOD reg THx (8 bits) TRx TCON reg Figure 10-7. Mode 2 Autoreload Period Formula TFxPER= 54 6 ⋅ (256 – THx) FTIMx AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 10.3.4 Mode 3 (2 8-bit Timers) Mode 3 configures Timer 0 such that registers TL0 and TH0 operate as separate 8-bit Timers (see Figure 10-8). This mode is provided for applications requiring an additional 8-bit Timer or Counter. TL0 uses the Timer 0 control bits C/T0# and GATE0 in TMOD register, and TR0 and TF0 in TCON register in the normal manner. TH0 is locked into a Timer function (counting FTF1/6) and takes over use of the Timer 1 interrupt (TF1) and run control (TR1) bits. Thus, operation of Timer 1 is restricted when Timer 0 is in mode 3. Figure 10-7 gives the autoreload period calculation formulas for both TF0 and TF1 flags. Figure 10-8. Timer/Counter 0 in Mode 3: 2 8-bit Counters TIM0 CLOCK ÷6 0 1 TL0 (8 bits) Overflow TH0 (8 bits) Overflow TF0 TCON.5 T0 Timer 0 Interrupt Request C/T0# TMOD.2 INT0 GATE0 TR0 TMOD.3 TIM0 CLOCK TCON.4 ÷6 TF1 TCON.7 Timer 1 Interrupt Request TR1 TCON.6 Figure 10-9. Mode 3 Overflow Period Formula TF0PER = 10.4 6 ⋅ (256 – TL0) FTIM0 TF1PER = 6 ⋅ (256 – TH0) FTIM0 Timer 1 Timer 1 is identical to Timer 0 except for Mode 3 which is a hold-count mode. The following comments help to understand the differences: • Timer 1 functions as either a Timer or event Counter in three modes of operation. Figure 102 through Figure 10-6 show the logical configuration for modes 0, 1, and 2. Timer 1’s mode 3 is a hold-count mode. • Timer 1 is controlled by the four high-order bits of TMOD register (see Figure 51) and bits 2, 3, 6 and 7 of TCON register (see Figure 50). TMOD register selects the method of Timer gating (GATE1), Timer or Counter operation (C/T1#) and mode of operation (M11 and M01). TCON register provides Timer 1 control functions: overflow flag (TF1), run control bit (TR1), interrupt flag (IE1) and interrupt type control bit (IT1). • Timer 1 can serve as the Baud Rate Generator for the Serial Port. Mode 2 is best suited for this purpose. • For normal Timer operation (GATE1 = 0), setting TR1 allows TL1 to be incremented by the selected input. Setting GATE1 and TR1 allows external pin INT1 to control Timer operation. • Timer 1 overflow (count rolls over from all 1s to all 0s) sets the TF1 flag generating an interrupt request. 55 4109J–8051–10/06 10.4.1 • When Timer 0 is in mode 3, it uses Timer 1’s overflow flag (TF1) and run control bit (TR1). For this situation, use Timer 1 only for applications that do not require an interrupt (such as a Baud Rate Generator for the Serial Port) and switch Timer 1 in and out of mode 3 to turn it off and on. • It is important to stop the Timer/Counter before changing modes. Mode 0 (13-bit Timer) Mode 0 configures Timer 1 as a 13-bit Timer, which is set up as an 8-bit Timer (TH1 register) with a modulo-32 prescaler implemented with the lower 5 bits of the TL1 register (see Figure 102). The upper 3 bits of TL1 register are ignored. Prescaler overflow increments TH1 register. 10.4.2 Mode 1 (16-bit Timer) Mode 1 configures Timer 1 as a 16-bit Timer with TH1 and TL1 registers connected in cascade (see Figure 10-4). The selected input increments TL1 register. 10.4.3 Mode 2 (8-bit Timer with Auto-Reload) Mode 2 configures Timer 1 as an 8-bit Timer (TL1 register) with automatic reload from TH1 register on overflow (see Figure 10-6). TL1 overflow sets TF1 flag in TCON register and reloads TL1 with the contents of TH1, which is preset by software. The reload leaves TH1 unchanged. 10.4.4 Mode 3 (Halt) Placing Timer 1 in mode 3 causes it to halt and hold its count. This can be used to halt Timer 1 when TR1 run control bit is not available i.e. when Timer 0 is in mode 3. 10.5 Interrupt Each Timer handles one interrupt source that is the timer overflow flag TF0 or TF1. This flag is set every time an overflow occurs. Flags are cleared when vectoring to the Timer interrupt routine. Interrupts are enabled by setting ETx bit in IEN0 register. This assumes interrupts are globally enabled by setting EA bit in IEN0 register. Figure 10-10. Timer Interrupt System Timer 0 Interrupt Request TF0 TCON.5 ET0 IEN0.1 Timer 1 Interrupt Request TF1 TCON.7 ET1 IEN0.3 10.6 Registers Table 50. TCON Register TCON (S:88h) – Timer/Counter Control Register 56 7 6 5 4 3 2 1 0 TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Bit Number Bit Mnemonic Description 7 TF1 Timer 1 Overflow Flag Cleared by hardware when processor vectors to interrupt routine. Set by hardware on Timer/Counter overflow, when Timer 1 register overflows. 6 TR1 Timer 1 Run Control Bit Clear to turn off Timer/Counter 1. Set to turn on Timer/Counter 1. 5 TF0 Timer 0 Overflow Flag Cleared by hardware when processor vectors to interrupt routine. Set by hardware on Timer/Counter overflow, when Timer 0 register overflows. 4 TR0 Timer 0 Run Control Bit Clear to turn off Timer/Counter 0. Set to turn on Timer/Counter 0. 3 IE1 Interrupt 1 Edge Flag Cleared by hardware when interrupt is processed if edge-triggered (see IT1). Set by hardware when external interrupt is detected on INT1 pin. 2 IT1 Interrupt 1 Type Control Bit Clear to select low level active (level triggered) for external interrupt 1 (INT1). Set to select falling edge active (edge triggered) for external interrupt 1. 1 IE0 Interrupt 0 Edge Flag Cleared by hardware when interrupt is processed if edge-triggered (see IT0). Set by hardware when external interrupt is detected on INT0 pin. 0 IT0 Interrupt 0 Type Control Bit Clear to select low level active (level triggered) for external interrupt 0 (INT0). Set to select falling edge active (edge triggered) for external interrupt 0. Reset Value = 0000 0000b Table 51. TMOD Register TMOD (S:89h) – Timer/Counter Mode Control Register 7 6 5 4 3 2 1 0 GATE1 C/T1# M11 M01 GATE0 C/T0# M10 M00 57 4109J–8051–10/06 Bit Bit Number Mnemonic Description 7 GATE1 Timer 1 Gating Control Bit Clear to enable Timer 1 whenever TR1 bit is set. Set to enable Timer 1 only while INT1 pin is high and TR1 bit is set. 6 C/T1# Timer 1 Counter/Timer Select Bit Clear for Timer operation: Timer 1 counts the divided-down system clock. Set for Counter operation: Timer 1 counts negative transitions on external pin T1. 5 M11 4 M01 Timer 1 Mode Select Bits M11M01Operating mode 0 0 Mode 0: 8-bit Timer/Counter (TH1) with 5-bit prescaler (TL1). 0 1 Mode 1: 16-bit Timer/Counter. 1 0 Mode 2: 8-bit auto-reload Timer/Counter (TL1).(1) 1 1 Mode 3: Timer 1 halted. Retains count. 3 GATE0 Timer 0 Gating Control Bit Clear to enable Timer 0 whenever TR0 bit is set. Set to enable Timer/Counter 0 only while INT0 pin is high and TR0 bit is set. 2 C/T0# Timer 0 Counter/Timer Select Bit Clear for Timer operation: Timer 0 counts the divided-down system clock. Set for Counter operation: Timer 0 counts negative transitions on external pin T0. M10 1 M00 0 Notes: Timer 0 Mode Select Bit M10M00Operating mode 0 0Mode 0: 8-bit Timer/Counter (TH0) with 5-bit prescaler (TL0). 0 1Mode 1: 16-bit Timer/Counter. 1 0Mode 2: 8-bit auto-reload Timer/Counter (TL0).(2) 1 1Mode 3: TL0 is an 8-bit Timer/Counter. TH0 is an 8-bit Timer using Timer 1’s TR0 and TF0 bits. 1. Reloaded from TH1 at overflow. 2. Reloaded from TH0 at overflow. Reset Value = 0000 0000b Table 52. TH0 Register TH0 (S:8Ch) – Timer 0 High Byte Register 7 6 5 4 3 2 1 0 - - - - - - - - Bit Number Bit Mnemonic Description 7:0 High Byte of Timer 0 Reset Value = 0000 0000b Table 53. TL0 Register TL0 (S:8Ah) – Timer 0 Low Byte Register 58 7 6 5 4 3 2 1 0 - - - - - - - - AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Bit Number Bit Mnemonic Description 7:0 Low Byte of Timer 0 Reset Value = 0000 0000b Table 54. TH1 Register TH1 (S:8Dh) – Timer 1 High Byte Register 7 6 5 4 3 2 1 0 - - - - - - - - Bit Number Bit Mnemonic Description 7:0 High Byte of Timer 1 Reset Value = 0000 0000b Table 55. TL1 Register TL1 (S:8Bh) – Timer 1 Low Byte Register 7 6 5 4 3 2 1 0 - - - - - - - - Bit Number Bit Mnemonic Description 7:0 Low Byte of Timer 1 Reset Value = 0000 0000b 59 4109J–8051–10/06 11. Watchdog Timer The AT8xC51SND1C implement a hardware Watchdog Timer (WDT) that automatically resets the chip if it is allowed to time out. The WDT provides a means of recovering from routines that do not complete successfully due to software or hardware malfunctions. 11.1 Description The WDT consists of a 14-bit prescaler followed by a 7-bit programmable counter. As shown in Figure 11-1, the 14-bit prescaler is fed by the WDT clock detailed in Section “Watchdog Clock Controller”, page 60. The Watchdog Timer Reset register (WDTRST, see Table 57) provides control access to the WDT, while the Watchdog Timer Program register (WDTPRG, see Figure 11-4) provides timeout period programming. Three operations control the WDT: • Chip reset clears and disables the WDT. • Programming the time-out value to the WDTPRG register. • Writing a specific 2-Byte sequence to the WDTRST register clears and enables the WDT. Figure 11-1. WDT Block Diagram WDT CLOCK 14-bit Prescaler ÷6 7-bit Counter OV RST RST To internal reset SET WTO2:0 1Eh-E1h Decoder System Reset RST WDTPRG.2:0 EN MATCH OSC CLOCK Pulse Generator RST WDTRST 11.2 Watchdog Clock Controller As shown in Figure 11-2 the WDT clock (FWDT) is derived from either the peripheral clock (FPER) or the oscillator clock (FOSC) depending on the WTX2 bit in CKCON register. These clocks are issued from the Clock Controller block as detailed in Section "Clock Controller", page 12. When WTX2 bit is set, the WDT clock frequency is fixed and equal to the oscillator clock frequency divided by 2. When cleared, the WDT clock frequency is equal to the oscillator clock frequency divided by 2 in standard mode or to the oscillator clock frequency in X2 mode. Figure 11-2. WDT Clock Controller and Symbol PER CLOCK 0 WDT Clock 1 OSC CLOCK ÷2 WDT CLOCK WDT Clock Symbol WTX2 CKCON.6 60 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 11.3 Watchdog Operation After reset, the WDT is disabled. The WDT is enabled by writing the sequence 1Eh and E1h into the WDTRST register. As soon as it is enabled, there is no way except the chip reset to disable it. If it is not cleared using the previous sequence, the WDT overflows and forces a chip reset. This overflow generates a high level 96 oscillator periods pulse on the RST pin to globally reset the application (refer to Section “Power Management”, page 47). The WDT time-out period can be adjusted using WTO2:0 bits located in the WDTPRG register accordingly to the formula shown in Figure 11-3. In this formula, WTOval represents the decimal value of WTO2:0 bits. Table 56 reports the time-out period depending on the WDT frequency. Figure 11-3. WDT Time-Out Formula 6 ⋅ ((214 ⋅ 2WTOval) – 1) FWDT WDTTO= Table 56. WDT Time-Out Computation FWDT (ms) Notes: 11.3.1 10 MHz(1) 12 MHz(2) 16 MHz(2) 20 MHz(2) 12.28 9.83 8.19 6.14 4.92 32.77 24.57 19.66 16.38 12.28 9.83 0 65.54 49.14 39.32 32.77 24.57 19.66 1 1 131.07 98.28 78.64 65.54 49.14 39.32 1 0 0 262.14 196.56 157.29 131.07 98.28 78.64 1 0 1 524.29 393.1 314.57 262.14 196.56 157.29 1 1 0 1049 786.24 629.15 524.29 393.12 314.57 1 1 1 2097 1572 1258 1049 786.24 629.15 6 MHz (1) WTO2 WTO1 WTO0 0 0 0 16.38 0 0 1 0 1 0 (1) 8 MHz 1. These frequencies are achieved in X1 mode or in X2 mode when WTX2 = 1: FWDT = FOSC ÷ 2. 2. These frequencies are achieved in X2 mode when WTX2 = 0: FWDT = FOSC. WDT Behavior during Idle and Power-down Modes Operation of the WDT during power reduction modes deserves special attention. The WDT continues to count while the AT8xC51SND1C is in Idle mode. This means that you must dedicate some internal or external hardware to service the WDT during Idle mode. One approach is to use a peripheral Timer to generate an interrupt request when the Timer overflows. The interrupt service routine then clears the WDT, reloads the peripheral Timer for the next service period and puts the AT8xC51SND1C back into Idle mode. The Power-down mode stops all phase clocks. This causes the WDT to stop counting and to hold its count. The WDT resumes counting from where it left off if the Power-down mode is terminated by INT0, INT1 or keyboard interrupt. To ensure that the WDT does not overflow shortly after exiting the Power-down mode, it is recommended to clear the WDT just before entering Power-down mode. The WDT is cleared and disabled if the Power-down mode is terminated by a reset. 61 4109J–8051–10/06 11.4 Registers Table 57. WDTRST Register WDTRST (S:A6h Write only) – Watchdog Timer Reset Register 7 6 5 4 3 2 1 0 - - - - - - - - Bit Number 7-0 Bit Mnemonic Description - Watchdog Control Value Reset Value = XXXX XXXXb Figure 11-4. WDTPRG Register WDTPRG (S:A7h) – Watchdog Timer Program Register 7 6 5 4 3 2 1 0 - - - - - WTO2 WTO1 WTO0 Bit Number Bit Mnemonic Description 7-3 - 2-0 WTO2:0 Reserved The value read from these bits is indeterminate. Do not set these bits. Watchdog Timer Time-Out Selection Bits Refer to Table 56 for time-out periods. Reset Value = XXXX X000b 62 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 12. MP3 Decoder The AT8xC51SND1C implement a MPEG I/II audio layer 3 decoder better known as MP3 decoder. In MPEG I (ISO 11172-3) three layers of compression have been standardized supporting three sampling frequencies: 48, 44.1, and 32 kHz. Among these layers, layer 3 allows highest compression rate of about 12:1 while still maintaining CD audio quality. For example, 3 minutes of CD audio (16-bit PCM, 44.1 kHz) data, which needs about 32M bytes of storage, can be encoded into only 2.7M bytes of MPEG I audio layer 3 data. In MPEG II (ISO 13818-3), three additional sampling frequencies: 24, 22.05, and 16 kHz are supported for low bit rates applications. The AT8xC51SND1C can decode in real-time the MPEG I audio layer 3 encoded data into a PCM audio data, and also supports MPEG II audio layer 3 additional frequencies. Additional features are supported by the AT8xC51SND1C MP3 decoder such as volume control, bass, medium, and treble controls, bass boost effect and ancillary data extraction. 12.1 12.1.1 Decoder Description The C51 core interfaces to the MP3 decoder through nine special function registers: MP3CON, the MP3 Control register (see Table 62); MP3STA, the MP3 Status register (see Table 63); MP3DAT, the MP3 Data register (see Table 64); MP3ANC, the Ancillary Data register (see Table 66); MP3VOL and MP3VOR, the MP3 Volume Left and Right Control registers (see Table 67 and Table 68); MP3BAS, MP3MED, and MP3TRE, the MP3 Bass, Medium, and Treble Control registers (see Table 69, Table 70, and Table 71); and MPCLK, the MP3 Clock Divider register (see Table 72). Figure 12-1 shows the MP3 decoder block diagram. Figure 12-1. MP3 Decoder Block Diagram Audio Data From C51 8 1K Bytes Frame Buffer MP3DAT Header Checker Huffman Decoder MPxREQ ERRxxx MPFS1:0 MPVER MP3STA1.n MP3STA.5:3 MP3STA.2:1 MP3STA.0 Dequantizer Stereo Processor Side Information MP3 CLOCK Ancillary Buffer MP3ANC MPEN MP3CON.7 Anti-Aliasing MPBBST MP3CON.6 12.1.2 MP3VOL IMDCT MP3VOR MP3BAS Sub-band Synthesis MP3MED 16 Decoded Data To Audio Interface MP3TRE MP3 Data The MP3 decoder does not start any frame decoding before having a complete frame in its input buffer(1). In order to manage the load of MP3 data in the frame buffer, a hardware handshake 63 4109J–8051–10/06 consisting of data request and data acknowledgment is implemented. Each time the MP3 decoder needs MP3 data, it sets the MPREQ, MPFREQ and MPBREQ flags respectively in MP3STA and MP3STA1 registers. MPREQ flag can generate an interrupt if enabled as explained in Section “Interrupt”. The CPU must then load data in the buffer by writing it through MP3DAT register thus acknowledging the previous request. As shown in Figure 12-2, the MPFREQ flag remains set while data (i.e a frame) is requested by the decoder. It is cleared when no more data is requested and set again when new data are requested. MPBREQ flag toggles at every Byte writing. Note: 1. The first request after enable, consists in 1024 Bytes of data to fill in the input buffer. Figure 12-2. Data Timing Diagram MPREQ Flag Cleared when Reading MP3STA MPFREQ Flag MPBREQ Flag Write to MP3DAT 12.1.3 MP3 Clock The MP3 decoder clock is generated by division of the PLL clock. The division factor is given by MPCD4:0 bits in MP3CLK register. Figure 12-3 shows the MP3 decoder clock generator and its calculation formula. The MP3 decoder clock frequency depends only on the incoming MP3 frames. Figure 12-3. MP3 Clock Generator and Symbol MP3CLK PLL CLOCK MPCD4:0 MP3 CLOCK MP3 Decoder Clock MP3 Clock Symbol PLLclk MP3clk = ---------------------------MPCD + 1 As soon as the frame header has been decoded and the MPEG version extracted, the minimum MP3 input frequency must be programmed according to Table 58. Table 58. MP3 Clock Frequency 12.2 12.2.1 MPEG Version Minimum MP3 Clock (MHz) I 21 II 10.5 Audio Controls Volume Control The MP3 decoder implements volume control on both right and left channels. The MP3VOR and MP3VOL registers allow a 32-step volume control according to Table 59. 64 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Table 59. Volume Control 12.2.2 VOL4:0 or VOR4:0 Volume Gain (dB) 00000 Mute 00001 -33 00010 -27 11110 -1.5 11111 0 Equalization Control Sound can be adjusted using a 3-band equalizer: a bass band under 750 Hz, a medium band from 750 Hz to 3300 Hz and a treble band over 3300 Hz. The MP3BAS, MP3MED, and MP3TRE registers allow a 32-step gain control in each band according to Table 60. Table 60. Bass, Medium, Treble Control 12.2.3 BAS4:0 or MED4:0 or TRE4:0 Gain (dB) 00000 -∞ 00001 -14 00010 -10 11110 +1 11111 +1.5 Special Effect The MPBBST bit in MP3CON register allows enabling of a bass boost effect with the following characteristics: gain increase of +9 dB in the frequency under 375 Hz. 12.3 Decoding Errors The three different errors that can appear during frame processing are detailed in the following sections. All these errors can trigger an interrupt as explained in Section "Interrupt", page 66. 12.3.1 Layer Error The ERRSYN flag in MP3STA is set when a non-supported layer is decoded in the header of the frame that has been sent to the decoder. 12.3.2 Synchronization Error The ERRSYN flag in MP3STA is set when no synchronization pattern is found in the data that have been sent to the decoder. 12.3.3 CRC Error When the CRC of a frame does not match the one calculated, the flag ERRCRC in MP3STA is set. In this case, depending on the CRCEN bit in MP3CON, the frame is played or rejected. In both cases, noise may appear at audio output. 65 4109J–8051–10/06 12.4 Frame Information The MP3 frame header contains information on the audio data contained in the frame. These informations is made available in the MP3STA register for you information. MPVER and MPFS1:0 bits allow decoding of the sampling frequency according to Table 61. MPVER bit gives the MPEG version (2 or 1). Table 61. MP3 Frame Frequency Sampling 12.5 MPVER MPFS1 MPFS0 Fs (kHz) 0 0 0 22.05 (MPEG II) 0 0 1 24 (MPEG II) 0 1 0 16 (MPEG II) 0 1 1 Reserved 1 0 0 44.1 (MPEG I) 1 0 1 48 (MPEG I) 1 1 0 32 (MPEG I) 1 1 1 Reserved Ancillary Data MP3 frames also contain data bits called ancillary data. These data are made available in the MP3ANC register for each frame. As shown in Figure 12-4, the ancillary data are available by Bytes when MPANC flag in MP3STA register is set. MPANC flag is set when the ancillary buffer is not empty (at least one ancillary data is available) and is cleared only when there is no more ancillary data in the buffer. This flag can generate an interrupt as explained in Section "Interrupt", page 66. When set, software must read all Bytes to empty the ancillary buffer. Figure 12-4. Ancillary Data Block Diagram Ancillary Data To C51 12.6 12.6.1 8 MP3ANC 8 7-Byte Ancillary Buffer MPANC MP3STA.7 Interrupt Description As shown in Figure 12-5, the MP3 decoder implements five interrupt sources reported in ERRCRC, ERRSYN, ERRLAY, MPREQ, and MPANC flags in MP3STA register. All these sources are maskable separately using MSKCRC, MSKSYN, MSKLAY, MSKREQ, and MSKANC mask bits respectively in MP3CON register. The MP3 interrupt is enabled by setting EMP3 bit in IEN0 register. This assumes interrupts are globally enabled by setting EA bit in IEN0 register. All interrupt flags but MPREQ and MPANC are cleared when reading MP3STA register. The MPREQ flag is cleared by hardware when no more data is requested (see Figure 12-2) and MPANC flag is cleared by hardware when the ancillary buffer becomes empty. 66 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 12-5. MP3 Decoder Interrupt System MPANC MP3STA.7 MSKANC MP3CON.4 MPREQ MP3STA.6 MSKREQ ERRLAY MP3 Decoder Interrupt Request MP3CON.3 MP3STA.5 ERRSYN MSKLAY EMP3 MP3CON.2 IEN0.5 MP3STA.4 MSKSYN ERRCRC MP3CON.1 MP3STA.3 MSKCRC MP3CON.0 12.6.2 Management Reading the MP3STA register automatically clears the interrupt flags (acknowledgment) except the MPREQ and MPANC flags. This implies that register content must be saved and tested, interrupt flag by interrupt flag to be sure not to forget any interrupts. 67 4109J–8051–10/06 Figure 12-6. MP3 Interrupt Service Routine Flow MP3 Decoder ISR Read MP3STA Data Request? MPFREQ = 1? Data Request Handler Ancillary Data?(1) MPANC = 1? Write MP3 Data to MP3DAT Ancillary Data Handler Sync Error?(1) ERRSYN = 1? Read ANN2:0 Ancillary Bytes From MP3ANC Synchro Error Handler Layer Error?(1) ERRSYN = 1? Reload MP3 Frame Through MP3DAT Layer Error Handler CRC Error Handler Load New MP3 Frame Through MP3DAT Note: 12.7 1. Test these bits only if needed (unmasked interrupt). Registers Table 62. MP3CON Register MP3CON (S:AAh) – MP3 Decoder Control Register 7 6 5 4 3 2 1 0 MPEN MPBBST CRCEN MSKANC MSKREQ MSKLAY MSKSYN MSKCRC Bit Number 7 68 Bit Mnemonic Description MPEN MP3 Decoder Enable Bit Set to enable the MP3 decoder. Clear to disable the MP3 decoder. AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Bit Number Bit Mnemonic Description MPBBST Bass Boost Bit Set to enable the bass boost sound effect. Clear to disable the bass boost sound effect. 5 CRCEN CRC Check Enable Bit Set to enable processing of frame that contains CRC error. Frame is played whatever the error. Clear to disable processing of frame that contains CRC error. Frame is skipped. 4 MSKANC MPANC Flag Mask Bit Set to prevent the MPANC flag from generating a MP3 interrupt. Clear to allow the MPANC flag to generate a MP3 interrupt. 3 MSKREQ MPREQ Flag Mask Bit Set to prevent the MPREQ flag from generating a MP3 interrupt. Clear to allow the MPREQ flag to generate a MP3 interrupt. 2 MSKLAY ERRLAY Flag Mask Bit Set to prevent the ERRLAY flag from generating a MP3 interrupt. Clear to allow the ERRLAY flag to generate a MP3 interrupt. 1 MSKSYN ERRSYN Flag Mask Bit Set to prevent the ERRSYN flag from generating a MP3 interrupt. Clear to allow the ERRSYN flag to generate a MP3 interrupt. 0 MSKCRC ERRCRC Flag Mask Bit Set to prevent the ERRCRC flag from generating a MP3 interrupt. Clear to allow the ERRCRC flag to generate a MP3 interrupt. 6 Reset Value = 0011 1111b Table 63. MP3STA Register MP3STA (S:C8h Read Only) – MP3 Decoder Status Register 7 6 5 4 3 2 1 0 MPANC MPREQ ERRLAY ERRSYN ERRCRC MPFS1 MPFS0 MPVER Bit Number Bit Mnemonic Description 7 MPANC Ancillary Data Available Flag Set by hardware as soon as one ancillary data is available (buffer not empty). Cleared by hardware when no more ancillary data is available (buffer empty). 6 MPREQ MP3 Data Request Flag Set by hardware when MP3 decoder request data. Cleared when reading MP3STA. 5 ERRLAY Invalid Layer Error Flag Set by hardware when an invalid layer is encountered. Cleared when reading MP3STA. 4 ERRSYN Frame Synchronization Error Flag Set by hardware when no synchronization pattern is encountered in a frame. Cleared when reading MP3STA. 3 ERRCRC CRC Error Flag Set by hardware when a frame handling CRC is corrupted. Cleared when reading MP3STA. 69 4109J–8051–10/06 Bit Number Bit Mnemonic Description 2-1 MPFS1:0 0 MPVER Frequency Sampling Bits Refer to Table 61 for bits description. MPEG Version Bit Set by the MP3 decoder when the loaded frame is a MPEG I frame. Cleared by the MP3 decoder when the loaded frame is a MPEG II frame. Reset Value = 0000 0001b Table 64. MP3DAT Register MP3DAT (S:ACh) – MP3 Data Register 7 6 5 4 3 2 1 0 MPD7 MPD6 MPD5 MPD4 MPD3 MPD2 MPD1 MPD0 Bit Number 7-0 Bit Mnemonic Description MPD7:0 Input Stream Data Buffer 8-bit MP3 stream data input buffer. Reset Value = 0000 0000b Table 65. MP3STA1 Register MP3STA1 (S:AFh) – MP3 Decoder Status Register 1 7 6 5 4 3 2 1 0 - - - MPFREQ MPFREQ - - - Bit Number Bit Mnemonic Description Reserved The value read from these bits is always 0. Do not set these bits. 7-5 - 4 MPFREQ MP3 Frame Data Request Flag Set by hardware when MP3 decoder request data. Cleared when MP3 decoder no more request data . 3 MPBREQ MP3 Byte Data Request Flag Set by hardware when MP3 decoder request data. Cleared when writing to MP3DAT. 2-0 - Reserved The value read from these bits is always 0. Do not set these bits. Reset Value = 0001 0001b Table 66. MP3ANC Register MP3ANC (S:ADh Read Only) – MP3 Ancillary Data Register 70 7 6 5 4 3 2 1 0 AND7 AND6 AND5 AND4 AND3 AND2 AND1 AND0 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Bit Number 7-0 Bit Mnemonic Description AND7:0 Ancillary Data Buffer MP3 ancillary data Byte buffer. Reset Value = 0000 0000b Table 67. MP3VOL Register MP3VOL (S:9Eh) – MP3 Volume Left Control Register 7 6 5 4 3 2 1 0 - - - VOL4 VOL3 VOL2 VOL1 VOL0 Bit Number Bit Mnemonic Description 7-5 - Reserved The value read from these bits is always 0. Do not set these bits. 4-0 VOL4:0 Volume Left Value Refer to Table 59 for the left channel volume control description. Reset Value = 0000 0000b Table 68. MP3VOR Register MP3VOR (S:9Fh) – MP3 Volume Right Control Register 7 6 5 4 3 2 1 0 - - - VOR4 VOR3 VOR2 VOR1 VOR0 Bit Number Bit Mnemonic Description 7-5 - Reserved The value read from these bits is always 0. Do not set these bits. 4-0 VOR4:0 Volume Right Value Refer to Table 59 for the right channel volume control description. Reset Value = 0000 0000b Table 69. MP3BAS Register MP3BAS (S:B4h) – MP3 Bass Control Register 7 6 5 4 3 2 1 0 - - - BAS4 BAS3 BAS2 BAS1 BAS0 Bit Number Bit Mnemonic Description 7-5 - 4-0 BAS4:0 Reserved The value read from these bits is always 0. Do not set these bits. Bass Gain Value Refer to Table 60 for the bass control description. Reset Value = 0000 0000b 71 4109J–8051–10/06 Table 70. MP3MED Register MP3MED (S:B5h) – MP3 Medium Control Register 7 6 5 4 3 2 1 0 - - MED5 MED4 MED3 MED2 MED1 MED0 Bit Number Bit Mnemonic Description 7-6 - 5-0 MED5:0 Reserved The value read from these bits is always 0. Do not set these bits. Medium Gain Value Refer to Table 60 for the medium control description. Reset Value = 0000 0000b Table 71. MP3TRE Register MP3TRE (S:B6h) – MP3 Treble Control Register 7 6 5 4 3 2 1 0 - - TRE5 TRE4 TRE3 TRE2 TRE1 TRE0 Bit Number Bit Mnemonic Description 7-6 - 5-0 TRE5:0 Reserved The value read from these bits is always 0. Do not set these bits. Treble Gain Value Refer to Table 60 for the treble control description. Reset Value = 0000 0000b Table 72. MP3CLK Register MP3CLK (S:EBh) – MP3 Clock Divider Register 7 6 5 4 3 2 1 0 - - - MPCD4 MPCD3 MPCD2 MPCD1 MPCD0 Bit Number Bit Mnemonic Description 7-5 - 4-0 MPCD4:0 Reserved The value read from these bits is always 0. Do not set these bits. MP3 Decoder Clock Divider 5-bit divider for MP3 decoder clock generation. Reset Value = 0000 0000b 72 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 13. Audio Output Interface The AT8xC51SND1C implement an audio output interface allowing the audio bitstream to be output in various formats. It is compatible with right and left justification PCM and I2S formats and thanks to the on-chip PLL (see Section “Clock Controller”, page 12) allows connection of almost all of the commercial audio DAC families available on the market. The audio bitstream can be from 2 different types: 13.1 • The MP3 decoded bitstream coming from the MP3 decoder for playing songs. • The audio bitstream coming from the MCU for outputting voice or sounds. Description The C51 core interfaces to the audio interface through five special function registers: AUDCON0 and AUDCON1, the Audio Control registers (see Table 74 and Table 75); AUDSTA, the Audio Status register (see Table 76); AUDDAT, the Audio Data register (see Table 77); and AUDCLK, the Audio Clock Divider register (see Table 78). Figure 13-1 shows the audio interface block diagram, blocks are detailed in the following sections. Figure 13-1. Audio Interface Block Diagram SCLK AUD CLOCK DCLK Clock Generator 0 DSEL AUDEN 1 AUDCON1.0 Data Ready HLR DSIZ AUDCON0.0 AUDCON0.1 POL AUDCON0.2 Audio Data From MP3 Decoder 16 MP3 Buffer 16 0 16 Sample Request To MP3 Decoder DRQEN AUDCON1.6 Data Converter DOUT 1 JUST4:0 SRC AUDCON0.7:3 AUDCON1.7 SREQ Audio Data From C51 8 Audio Buffer AUDDAT AUDSTA.7 UDRN AUDSTA.6 AUBUSY DUP1:0 AUDSTA.5 AUDCON1.2:1 13.2 Clock Generator The audio interface clock is generated by division of the PLL clock. The division factor is given by AUCD4:0 bits in CLKAUD register. Figure 13-2 shows the audio interface clock generator 73 4109J–8051–10/06 and its calculation formula. The audio interface clock frequency depends on the incoming MP3 frames and the audio DAC used. Figure 13-2. Audio Clock Generator and Symbol AUDCLK PLL CLOCK AUCD4:0 Audio Interface Clock PLLclk AUDclk = --------------------------AUCD + 1 AUD CLOCK Audio Clock Symbol As soon as audio interface is enabled by setting AUDEN bit in AUDCON1 register, the master clock generated by the PLL is output on the SCLK pin which is the DAC system clock. This clock is output at 256 or 384 times the sampling frequency depending on the DAC capabilities. HLR bit in AUDCON0 register must be set according to this rate for properly generating the audio bit clock on the DCLK pin and the word selection clock on the DSEL pin. These clocks are not generated when no data is available at the data converter input. For DAC compatibility, the bit clock frequency is programmable for outputting 16 bits or 32 bits per channel using the DSIZ bit in AUDCON0 register (see Section "Data Converter", page 74), and the word selection signal is programmable for outputting left channel on low or high level according to POL bit in AUDCON0 register as shown in Figure 13-3. Figure 13-3. DSEL Output Polarity 13.3 POL = 0 Left Channel Right Channel POL = 1 Left Channel Right Channel Data Converter The data converter block converts the audio stream input from the 16-bit parallel format to a serial format. For accepting all PCM formats and I2S format, JUST4:0 bits in AUDCON0 register are used to shift the data output point. As shown in Figure 13-4, these bits allow MSB justification by setting JUST4:0 = 00000, LSB justification by setting JUST4:0 = 10000, I2S Justification by setting JUST4:0 = 00001, and more than 16-bit LSB justification by filling the low significant bits with logic 0. 74 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 13-4. Audio Output Format DSEL DCLK DOUT Left Channel 1 2 3 Right Channel 13 14 15 LSB MSB B14 16 B1 1 2 3 13 14 15 LSB MSB B14 16 B1 I2S Format with DSIZ = 0 and JUST4:0 = 00001. DSEL DCLK Left Channel 1 DOUT 2 Right Channel 3 17 MSB B14 LSB 18 32 1 2 3 17 MSB B14 LSB 18 32 I2S Format with DSIZ = 1 and JUST4:0 = 00001. DSEL DCLK DOUT Left Channel 1 2 3 Right Channel 13 14 MSB B14 15 B1 16 1 2 3 13 14 LSB MSB B15 15 B1 16 LSB MSB/LSB Justified Format with DSIZ = 0 and JUST4:0 = 00000. DSEL DCLK Left Channel 1 16 DOUT 17 Right Channel 18 31 MSB B14 B1 32 1 16 LSB 17 18 31 MSB B14 B1 32 LSB 16-bit LSB Justified Format with DSIZ = 1 and JUST4:0 = 10000. DSEL DCLK Left Channel 1 DOUT 15 16 MSB B16 Right Channel 30 B2 31 B1 32 LSB 1 15 16 MSB B16 30 B2 31 B1 32 LSB 18-bit LSB Justified Format with DSIZ = 1 and JUST4:0 = 01110. The data converter receives its audio stream from 2 sources selected by the SRC bit in AUDCON1 register. When cleared, the audio stream comes from the MP3 decoder (see Section “MP3 Decoder”, page 63) for song playing. When set, the audio stream is coming from the C51 core for voice or sound playing. As soon as first audio data is input to the data converter, it enables the clock generator for generating the bit and word clocks. 13.4 Audio Buffer In voice or sound playing mode, the audio stream comes from the C51 core through an audio buffer. The data is in 8-bit format and is sampled at 8 kHz. The audio buffer adapts the sample format and rate. The sample format is extended to 16 bits by filling the LSB to 00h. Rate is adapted to the DAC rate by duplicating the data using DUP1:0 bits in AUDCON1 register according to Table 73. The audio buffer interfaces to the C51 core through three flags: the sample request flag (SREQ in AUDSTA register), the under-run flag (UNDR in AUDSTA register) and the busy flag (AUBUSY in AUDSTA register). SREQ and UNDR can generate an interrupt request as explained in Section "Interrupt Request", page 76. The buffer size is 8 Bytes large. SREQ is set when the samples number switches from 4 to 3 and reset when the samples number switches from 4 to 5; UNDR is set when the buffer becomes empty signaling that the audio interface ran out of samples; and AUBUSY is set when the buffer is full. 75 4109J–8051–10/06 Table 73. Sample Duplication Factor 13.5 DUP1 DUP0 Factor 0 0 No sample duplication, DAC rate = 8 kHz (C51 rate). 0 1 One sample duplication, DAC rate = 16 kHz (2 x C51 rate). 1 0 2 samples duplication, DAC rate = 32 kHz (4 x C51 rate). 1 1 Three samples duplication, DAC rate = 48 kHz (6 x C51 rate). MP3 Buffer In song playing mode, the audio stream comes from the MP3 decoder through a buffer. The MP3 buffer is used to store the decoded MP3 data and interfaces to the decoder through a 16bit data input and data request signal. This signal asks for data when the buffer has enough space to receive new data. Data request is conditioned by the DREQEN bit in AUDCON1 register. When set, the buffer requests data to the MP3 decoder. When cleared no more data is requested but data are output until the buffer is empty. This bit can be used to suspend the audio generation (pause mode). 13.6 Interrupt Request The audio interrupt request can be generated by 2 sources when in C51 audio mode: a sample request when SREQ flag in AUDSTA register is set to logic 1, and an under-run condition when UDRN flag in AUDSTA register is set to logic 1. Both sources can be enabled separately by masking one of them using the MSREQ and MUDRN bits in AUDCON1 register. A global enable of the audio interface is provided by setting the EAUD bit in IEN0 register. The interrupt is requested each time one of the 2 sources is set to one. The source flags are cleared by writing some data in the audio buffer through AUDDAT, but the global audio interrupt flag is cleared by hardware when the interrupt service routine is executed. Figure 13-5. Audio Interface Interrupt System UDRN AUDSTA.6 Audio Interrupt Request MUDRN AUDCON1.4 SREQ EAUD AUDSTA.7 IEN0.6 MSREQ AUDCON1.5 13.7 MP3 Song Playing In MP3 song playing mode, the operations to do are to configure the PLL and the audio interface according to the DAC selected. The audio clock is programmed to generate the 256·Fs or 384·Fs as explained in Section "Clock Generator", page 73. Figure 13-6 shows the configuration flow of the audio interface when in MP3 song mode. 76 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 13-6. MP3 Mode Audio Configuration Flow MP3 Mode Configuration Enable DAC System Clock AUDEN = 1 Program Audio Clock Configure Interface HLR = X DSIZ = X POL = X JUST4:0 = XXXXXb SRC = 0 13.8 Wait For DAC Set-up Time Enable Data Request DRQEN = 1 Voice or Sound Playing In voice or sound playing mode, the operations required are to configure the PLL and the audio interface according to the DAC selected. The audio clock is programmed to generate the 256·Fs or 384·Fs as for the MP3 playing mode. The data flow sent by the C51 is then regulated by interrupt and data is loaded 4 Bytes by 4 Bytes. Figure 13-7 shows the configuration flow of the audio interface when in voice or sound mode. Figure 13-7. Voice or Sound Mode Audio Flows Voice/Song Mode Configuration Audio Interrupt Service Routine Wait for DAC Enable Time Program Audio Clock Configure Interface HLR = X DSIZ = X POL = X JUST4:0 = XXXXXb DUP1:0 = XX Enable DAC System Clock AUDEN = 1 Sample Request? SREQ = 1? Select Audio SRC = 1 Load 4 Samples in the Audio Buffer Under-run Condition1 Load 8 Samples in the Audio Buffer Enable Interrupt Set MSREQ & MUDRN1 EAUD = 1 Note: 1. An under-run occurrence signifies that C51 core did not respond to the previous sample request interrupt. It may never occur for a correct voice/sound generation. It is the user’s responsibility to mask it or not. 13.9 Registers Table 74. AUDCON0 Register AUDCON0 (S:9Ah) – Audio Interface Control Register 0 7 6 5 4 3 2 1 0 JUST4 JUST3 JUST2 JUST1 JUST0 POL DSIZ HLR 77 4109J–8051–10/06 Bit Number Bit Mnemonic Description Audio Stream Justification Bits Refer to Section "Data Converter", page 74 for bits description. 7-3 JUST4:0 2 POL DSEL Signal Output Polarity Set to output the left channel on high level of DSEL output (PCM mode). Clear to output the left channel on the low level of DSEL output (I2S mode). 1 DSIZ Audio Data Size Set to select 32-bit data output format. Clear to select 16-bit data output format. 0 HLR High/Low Rate Bit Set by software when the PLL clock frequency is 384·Fs. Clear by software when the PLL clock frequency is 256·Fs. Reset Value = 0000 1000b Table 75. AUDCON1 Register AUDCON1 (S:9Bh) – Audio Interface Control Register 1 7 6 5 4 3 2 1 0 SRC DRQEN MSREQ MUDRN - DUP1 DUP0 AUDEN Bit Number Bit Mnemonic Description 7 SRC Audio Source Bit Set to select C51 as audio source for voice or sound playing. Clear to select the MP3 decoder output as audio source for song playing. 6 DRQEN MP3 Decoded Data Request Enable Bit Set to enable data request to the MP3 decoder and to start playing song. Clear to disable data request to the MP3 decoder. 5 MSREQ Audio Sample Request Flag Mask Bit Set to prevent the SREQ flag from generating an audio interrupt. Clear to allow the SREQ flag to generate an audio interrupt. 4 MUDRN Audio Sample Under-run Flag Mask Bit Set to prevent the UDRN flag from generating an audio interrupt. Clear to allow the UDRN flag to generate an audio interrupt. 3 - 2-1 DUP1:0 Audio Duplication Factor Refer to Table 73 for bits description. 0 AUDEN Audio Interface Enable Bit Set to enable the audio interface. Clear to disable the audio interface. Reserved The value read from this bit is always 0. Do not set this bit. Reset Value = 1011 0010b Table 76. AUDSTA Register AUDSTA (S:9Ch Read Only) – Audio Interface Status Register 78 7 6 5 4 3 2 1 0 SREQ UDRN AUBUSY - - - - - AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Bit Number Bit Mnemonic Description SREQ Audio Sample Request Flag Set in C51 audio source mode when the audio interface request samples (buffer half empty). This bit generates an interrupt if not masked and if enabled in IEN0. Cleared by hardware when samples are loaded in AUDDAT. UDRN Audio Sample Under-run Flag Set in C51 audio source mode when the audio interface runs out of samples (buffer empty). This bit generates an interrupt if not masked and if enabled in IEN0. Cleared by hardware when samples are loaded in AUDDAT. 5 AUBUSY Audio Interface Busy Bit Set in C51 audio source mode when the audio interface can not accept more sample (buffer full). Cleared by hardware when buffer is no more full. 4-0 - 7 6 Reserved The value read from these bits is always 0. Do not set these bits. Reset Value = 1100 0000b Table 77. AUDDAT Register AUDDAT (S:9Dh) – Audio Interface Data Register 7 6 5 4 3 2 1 0 AUD7 AUD6 AUD5 AUD4 AUD3 AUD2 AUD1 AUD0 Bit Number 7-0 Bit Mnemonic Description AUD7:0 Audio Data 8-bit sampling data for voice or sound playing. Reset Value = 1111 1111b Table 78. AUDCLK Register AUDCLK (S:ECh) – Audio Clock Divider Register 7 6 5 4 3 2 1 0 - - - AUCD4 AUCD3 AUCD2 AUCD1 AUCD0 Bit Number Bit Mnemonic Description 7-5 - 4-0 AUCD4:0 Reserved The value read from these bits is always 0. Do not set these bits. Audio Clock Divider 5-bit divider for audio clock generation. Reset Value = 0000 0000b 79 4109J–8051–10/06 14. Universal Serial Bus The AT8xC51SND1C implements a USB device controller supporting full speed data transfer. In addition to the default control endpoint 0, it provides 2 other endpoints, which can be configured in control, bulk, interrupt or isochronous modes: • Endpoint 0: 32-Byte FIFO, default control endpoint • Endpoint 1, 2: 64-Byte Ping-pong FIFO, This allows the firmware to be developed conforming to most USB device classes, for example: 14.0.1 • USB Mass Storage Class Bulk-only Transport, Revision 1.0 - September 31, 1999 • USB Human Interface Device Class, Version 1.1 - April 7, 1999 • USB Device Firmware Upgrade Class, Revision 1.0 - May 13, 1999 USB Mass Storage Class Bulk-Only Transport Within the Bulk-only framework, the Control endpoint is only used to transport class-specific and standard USB requests for device set-up and configuration. One Bulk-out endpoint is used to transport commands and data from the host to the device. One Bulk in endpoint is used to transport status and data from the device to the host. The following AT8xC51SND1C configuration adheres to those requirements: 14.0.2 • Endpoint 0: 32 Bytes, Control In-Out • Endpoint 1: 64 Bytes, Bulk-in • Endpoint 2: 64 Bytes, Bulk-out USB Device Firmware Upgrade (DFU) The USB Device Firmware Update (DFU) protocol can be used to upgrade the on-chip Flash memory of the AT89C51SND1C. This allows installing product enhancements and patches to devices that are already in the field. 2 different configurations and descriptor sets are used to support DFU functions. The Run-Time configuration co-exist with the usual functions of the device, which is USB Mass Storage for AT89C51SND1C. It is used to initiate DFU from the normal operating mode. The DFU configuration is used to perform the firmware update after device re-configuration and USB reset. It excludes any other function. Only the default control pipe (endpoint 0) is used to support DFU services in both configurations. The only possible value for the MaxPacketSize in the DFU configuration is 32 Bytes, which is the size of the FIFO implemented for endpoint 0. 14.1 Description The USB device controller provides the hardware that the AT8xC51SND1C needs to interface a USB link to a data flow stored in a double port memory. It requires a 48 MHz reference clock provided by the clock controller as detailed in Section "Clock Controller", page 81. This clock is used to generate a 12 MHz Full Speed bit clock from the received USB differential data flow and to transmit data according to full speed USB device tolerance. Clock recovery is done by a Digital Phase Locked Loop (DPLL) block. The Serial Interface Engine (SIE) block performs NRZI encoding and decoding, bit stuffing, CRC generation and checking, and the serial-parallel data conversion. The Universal Function Interface (UFI) controls the interface between the data flow and the Dual Port RAM, but also the interface with the C51 core itself. 80 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 14-3 shows how to connect the AT8xC51SND1C to the USB connector. D+ and D- pins are connected through 2 termination resistors. A pull-up resistor is implemented on D+ to inform the host of a full speed device connection. Value of these resistors is detailed in the section “DC Characteristics”. Figure 14-1. USB Device Controller Block Diagram USB CLOCK D+ 48 MHz 12 MHz DPLL USB Buffer D- UFI To/From C51 Core SIE Figure 14-2. USB Connection VDD To Power Supply VBUS D+ RFS RUSB D- RUSB D+ D- GND VSS 14.1.1 Clock Controller The USB controller clock is generated by division of the PLL clock. The division factor is given by USBCD1:0 bits in USBCLK register (see Table 94). Figure 14-3 shows the USB controller clock generator and its calculation formula. The USB controller clock frequency must always be 48 MHz. Figure 14-3. USB Clock Generator and Symbol USBCLK PLL CLOCK USBCD1:0 48 MHz USB Clock PLLclk USBclk = -------------------------------USBCD + 1 14.1.2 USB CLOCK USB Clock Symbol Serial Interface Engine (SIE) The SIE performs the following functions: • NRZI data encoding and decoding. 81 4109J–8051–10/06 • Bit stuffing and unstuffing. • CRC generation and checking. • ACKs and NACKs automatic generation. • TOKEN type identifying. • Address checking. • Clock recovery (using DPLL). Figure 14-4. SIE Block Diagram End of Packet Detector SYNC Detector Start of Packet Detector NRZI ‘ NRZ Bit Unstuffing Packet Bit Counter Address Decoder Serial to Parallel Converter D+ DUSB 48 MHz CLOCK Clock Recover PID Decoder 8 Data Out SysClk (12 MHz) CRC5 & CRC16 Generator/Check USB Pattern Generator Parallel to Serial Converter Bit Stuffing NRZI Converter CRC16 Generator 14.1.3 8 Data In Function Interface Unit (UFI) The Function Interface Unit provides the interface between the AT8xC51SND1C and the SIE. It manages transactions at the packet level with minimal intervention from the device firmware, which reads and writes the endpoint FIFOs. Figure 14-6 shows typical USB IN and OUT transactions reporting the split in the hardware (UFI) and software (C51) load. 82 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 14-5. UFI Block Diagram 12 MHz DPLL Transfer Control FSM To/From SIE Endpoint Control USB side Asynchronous Information Endpoint 2 USBCON USBADDR USBINT USBIEN UEPNUM UEPCONX UEPSTAX UEPRST UEPINT UEPIEN UEPDATX UBYCTX UFNUMH UFNUML To/From C51 Core Endpoint Control C51 side Endpoint 1 Endpoint 0 Figure 14-6. USB Typical Transaction Load OUT Transactions: HOST OUT DATA0 (n Bytes) UFI C51 OUT ACK DATA1 C51 interrupt OUT DATA1 NACK ACK Endpoint FIFO read (n Bytes) IN Transactions: HOST IN UFI IN NACK Endpoint FIFO Write C51 14.2 14.2.1 IN DATA1 ACK DATA1 C51 interrupt Endpoint FIFO write Configuration General Configuration • USB controller enable Before any USB transaction, the 48 MHz required by the USB controller must be correctly generated (See “Clock Controller” on page 19). The USB controller should be then enabled by setting the EUSB bit in the USBCON register. • Set address After a Reset or a USB reset, the software has to set the FEN (Function Enable) bit in the USBADDR register. This action will allow the USB controller to answer to the requests sent at the address 0. When a SET_ADDRESS request has been received, the USB controller must only answer to the address defined by the request. The new address should be stored in the USBADDR register. The FEN bit and the FADDEN bit in the USBCON register should be set to allow the USB controller to answer only to requests sent at the new address. 83 4109J–8051–10/06 • Set configuration The CONFG bit in the USBCON register should be set after a SET_CONFIGURATION request with a non-zero value. Otherwise, this bit should be cleared. 14.2.2 Endpoint Configuration • Selection of an Endpoint The endpoint register access is performed using the UEPNUM register. The registers – UEPSTAX – UEPCONX – UEPDATX – UBYCTX Theses registers correspond to the endpoint whose number is stored in the UEPNUM register. To select an Endpoint, the firmware has to write the endpoint number in the UEPNUM register. Figure 14-7. Endpoint Selection Endpoint 0 UEPSTA0 UEPCON0 UEPDAT0 SFR Registers 0 UBYCT0 1 X UEPSTAX UEPCONX UEPDATX UBYCTX Endpoint 2 UEPSTA2 UEPCON2 UEPDAT2 2 UBYCT2 UEPNUM • Endpoint enable Before using an endpoint, this must be enabled by setting the EPEN bit in the UEPCONX register. An endpoint which is not enabled won’t answer to any USB request. The Default Control Endpoint (Endpoint 0) should always be enabled in order to answer to USB standard requests. • Endpoint type configuration All Standard Endpoints can be configured in Control, Bulk, Interrupt or Isochronous mode. The Ping-pong Endpoints can be configured in Bulk, Interrupt or Isochronous mode. The configuration of an endpoint is performed by setting the field EPTYPE with the following values: – Control: – Isochronous: EPTYPE = 01b EPTYPE = 00b – Bulk: EPTYPE = 10b – Interrupt: EPTYPE = 11b The Endpoint 0 is the Default Control Endpoint and should always be configured in Control type. • Endpoint direction configuration For Bulk, Interrupt and Isochronous endpoints, the direction is defined with the EPDIR bit of the UEPCONX register with the following values: 84 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C – IN: EPDIR = 1b – OUT: EPDIR = 0b For Control endpoints, the EPDIR bit has no effect. • Summary of Endpoint Configuration: Do not forget to select the correct endpoint number in the UEPNUM register before accessing endpoint specific registers. Table 79. Summary of Endpoint Configuration Endpoint Configuration • EPEN EPDIR EPTYPE UEPCONX Disabled 0b Xb XXb 0XXX XXXb Control 1b Xb 00b 80h Bulk-in 1b 1b 10b 86h Bulk-out 1b 0b 10b 82h Interrupt-In 1b 1b 11b 87h Interrupt-Out 1b 0b 11b 83h Isochronous-In 1b 1b 01b 85h Isochronous-Out 1b 0b 01b 81h Endpoint FIFO reset Before using an endpoint, its FIFO should be reset. This action resets the FIFO pointer to its original value, resets the Byte counter of the endpoint (UBYCTX register), and resets the data toggle bit (DTGL bit in UEPCONX). The reset of an endpoint FIFO is performed by setting to 1 and resetting to 0 the corresponding bit in the UEPRST register. For example, in order to reset the Endpoint number 2 FIFO, write 0000 0100b then 0000 0000b in the UEPRST register. Note that the endpoint reset doesn’t reset the bank number for ping-pong endpoints. 14.3 14.3.1 Read/Write Data FIFO Read Data FIFO The read access for each OUT endpoint is performed using the UEPDATX register. After a new valid packet has been received on an Endpoint, the data are stored into the FIFO and the Byte counter of the endpoint is updated (UBYCTX registers). The firmware has to store the endpoint Byte counter before any access to the endpoint FIFO. The Byte counter is not updated when reading the FIFO. To read data from an endpoint, select the correct endpoint number in UEPNUM and read the UEPDATX register. This action automatically decreases the corresponding address vector, and the next data is then available in the UEPDATX register. 14.3.2 Write Data FIFO The write access for each IN endpoint is performed using the UEPDATX register. To write a Byte into an IN endpoint FIFO, select the correct endpoint number in UEPNUM and write into the UEPDATX register. The corresponding address vector is automatically increased, and another write can be carried out. 85 4109J–8051–10/06 Warning 1: The Byte counter is not updated. Warning 2: Do not write more Bytes than supported by the corresponding endpoint. 14.3.3 FIFO Mapping Figure 14-8. Endpoint FIFO Configuration Endpoint 0 UEPSTA0 UEPCON0 UEPDAT0 SFR Registers 0 UBYCT0 1 X UEPSTAX UEPCONX UEPDATX UBYCTX Endpoint 2 UEPSTA2 UEPCON2 2 UEPDAT2 UBYCT2 UEPNUM 14.4 Bulk/Interrupt Transactions Bulk and Interrupt transactions are managed in the same way. 14.4.1 Bulk/Interrupt OUT Transactions in Standard Mode Figure 14-9. Bulk/Interrupt OUT transactions in Standard Mode HOST OUT C51 UFI DATA0 (n Bytes) ACK RXOUTB0 Endpoint FIFO Read Byte 1 OUT DATA1 Endpoint FIFO Read Byte 2 NAK OUT Endpoint FIFO Read Byte n DATA1 Clear RXOUTB0 NAK OUT DATA1 ACK RXOUTB0 Endpoint FIFO Read Byte 1 An endpoint should be first enabled and configured before being able to receive Bulk or Interrupt packets. When a valid OUT packet is received on an endpoint, the RXOUTB0 bit is set by the USB controller. This triggers an interrupt if enabled. The firmware has to select the corresponding endpoint, store the number of data Bytes by reading the UBYCTX register. If the received packet 86 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C is a ZLP (Zero Length Packet), the UBYCTX register value is equal to 0 and no data has to be read. When all the endpoint FIFO Bytes have been read, the firmware should clear the RXOUTB0 bit to allow the USB controller to accept the next OUT packet on this endpoint. Until the RXOUTB0 bit has been cleared by the firmware, the USB controller will answer a NAK handshake for each OUT requests. If the Host sends more Bytes than supported by the endpoint FIFO, the overflow data won’t be stored, but the USB controller will consider that the packet is valid if the CRC is correct and the endpoint Byte counter contains the number of Bytes sent by the Host. 14.4.2 Bulk/Interrupt OUT Transactions in Ping-pong Mode Figure 14-10. Bulk/Interrupt OUT Transactions in Ping-pong Mode HOST OUT C51 UFI DATA0 (n Bytes) ACK RXOUTB0 Endpoint FIFO bank 0 - Read Byte 1 OUT Endpoint FIFO bank 0 - Read Byte 2 DATA1 (m Bytes) ACK Endpoint FIFO bank 0 - Read Byte n Clear RXOUTB0 OUT RXOUTB1 DATA0 (p Bytes) Endpoint FIFO bank 1 - Read Byte 1 ACK Endpoint FIFO bank 1 - Read Byte 2 Endpoint FIFO bank 1 - Read Byte m Clear RXOUTB1 RXOUTB0 Endpoint FIFO bank 0 - Read Byte 1 Endpoint FIFO bank 0 - Read Byte 2 Endpoint FIFO bank 0 - Read Byte p Clear RXOUTB0 An endpoint should be first enabled and configured before being able to receive Bulk or Interrupt packets. When a valid OUT packet is received on the endpoint bank 0, the RXOUTB0 bit is set by the USB controller. This triggers an interrupt if enabled. The firmware has to select the corresponding endpoint, store the number of data Bytes by reading the UBYCTX register. If the received packet is a ZLP (Zero Length Packet), the UBYCTX register value is equal to 0 and no data has to be read. When all the endpoint FIFO Bytes have been read, the firmware should clear the RXOUB0 bit to allow the USB controller to accept the next OUT packet on the endpoint bank 0. This action switches the endpoint bank 0 and 1. Until the RXOUTB0 bit has been cleared by the firmware, the USB controller will answer a NAK handshake for each OUT requests on the bank 0 endpoint FIFO. When a new valid OUT packet is received on the endpoint bank 1, the RXOUTB1 bit is set by the USB controller. This triggers an interrupt if enabled. The firmware empties the bank 1 end- 87 4109J–8051–10/06 point FIFO before clearing the RXOUTB1 bit. Until the RXOUTB1 bit has been cleared by the firmware, the USB controller will answer a NAK handshake for each OUT requests on the bank 1 endpoint FIFO. The RXOUTB0 and RXOUTB1 bits are, alternatively, set by the USB controller at each new valid packet receipt. The firmware has to clear one of these 2 bits after having read all the data FIFO to allow a new valid packet to be stored in the corresponding bank. A NAK handshake is sent by the USB controller only if the banks 0 and 1 has not been released by the firmware. If the Host sends more Bytes than supported by the endpoint FIFO, the overflow data won’t be stored, but the USB controller will consider that the packet is valid if the CRC is correct. 14.4.3 Bulk/Interrupt IN Transactions in Standard Mode Figure 14-11. Bulk/Interrupt IN Transactions in Standard Mode HOST C51 UFI Endpoint FIFO Write Byte 1 IN Endpoint FIFO Write Byte 2 NAK Endpoint FIFO Write Byte n Set TXRDY IN DATA0 (n Bytes) ACK TXCMPL Clear TXCMPL Endpoint FIFO Write Byte 1 An endpoint should be first enabled and configured before being able to send Bulk or Interrupt packets. The firmware should fill the FIFO with the data to be sent and set the TXRDY bit in the UEPSTAX register to allow the USB controller to send the data stored in FIFO at the next IN request concerning this endpoint. To send a Zero Length Packet, the firmware should set the TXRDY bit without writing any data into the endpoint FIFO. Until the TXRDY bit has been set by the firmware, the USB controller will answer a NAK handshake for each IN requests. To cancel the sending of this packet, the firmware has to reset the TXRDY bit. The packet stored in the endpoint FIFO is then cleared and a new packet can be written and sent. When the IN packet has been sent and acknowledged by the Host, the TXCMPL bit in the UEPSTAX register is set by the USB controller. This triggers a USB interrupt if enabled. The firmware should clear the TXCMPL bit before filling the endpoint FIFO with new data. The firmware should never write more Bytes than supported by the endpoint FIFO. 88 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C All USB retry mechanisms are automatically managed by the USB controller. 14.4.4 Bulk/Interrupt IN Transactions in Ping-pong Mode Figure 14-12. Bulk/Interrupt IN transactions in Ping-pong mode HOST C51 UFI Endpoint FIFO bank 0 - Write Byte 1 IN Endpoint FIFO bank 0 - Write Byte 2 NACK Endpoint FIFO bank 0 - Write Byte n Set TXRDY IN Endpoint FIFO bank 1 - Write Byte 1 DATA0 (n Bytes) Endpoint FIFO bank 1 - Write Byte 2 ACK Endpoint FIFO bank 1 - Write Byte m TXCMPL Clear TXCMPL Set TXRDY IN DATA1 (m Bytes) Endpoint FIFO bank 0 - Write Byte 1 Endpoint FIFO bank 0 - Write Byte 2 ACK Endpoint FIFO bank 0 - Write Byte p TXCMPL Clear TXCMPL Set TXRDY IN DATA0 (p Bytes) Endpoint FIFO bank 1 - Write Byte 1 ACK An endpoint should be first enabled and configured before being able to send Bulk or Interrupt packets. The firmware should fill the FIFO bank 0 with the data to be sent and set the TXRDY bit in the UEPSTAX register to allow the USB controller to send the data stored in FIFO at the next IN request concerning the endpoint. The FIFO banks are automatically switched, and the firmware can immediately write into the endpoint FIFO bank 1. When the IN packet concerning the bank 0 has been sent and acknowledged by the Host, the TXCMPL bit is set by the USB controller. This triggers a USB interrupt if enabled. The firmware should clear the TXCMPL bit before filling the endpoint FIFO bank 0 with new data. The FIFO banks are then automatically switched. When the IN packet concerning the bank 1 has been sent and acknowledged by the Host, the TXCMPL bit is set by the USB controller. This triggers a USB interrupt if enabled. The firmware should clear the TXCMPL bit before filling the endpoint FIFO bank 1 with new data. The bank switch is performed by the USB controller each time the TXRDY bit is set by the firmware. Until the TXRDY bit has been set by the firmware for an endpoint bank, the USB controller will answer a NAK handshake for each IN requests concerning this bank. Note that in the example above, the firmware clears the Transmit Complete bit (TXCBulk-outMPL) before setting the Transmit Ready bit (TXRDY). This is done in order to avoid the firmware to clear at the same time the TXCMPL bit for for bank 0 and the bank 1. 89 4109J–8051–10/06 The firmware should never write more Bytes than supported by the endpoint FIFO. 14.5 14.5.1 Control Transactions Setup Stage The DIR bit in the UEPSTAX register should be at 0. Receiving Setup packets is the same as receiving Bulk Out packets, except that the RXSETUP bit in the UEPSTAX register is set by the USB controller instead of the RXOUTB0 bit to indicate that an Out packet with a Setup PID has been received on the Control endpoint. When the RXSETUP bit has been set, all the other bits of the UEPSTAX register are cleared and an interrupt is triggered if enabled. The firmware has to read the Setup request stored in the Control endpoint FIFO before clearing the RXSETUP bit to free the endpoint FIFO for the next transaction. 14.5.2 Data Stage: Control Endpoint Direction The data stage management is similar to Bulk management. A Control endpoint is managed by the USB controller as a full-duplex endpoint: IN and OUT. All other endpoint types are managed as half-duplex endpoint: IN or OUT. The firmware has to specify the control endpoint direction for the data stage using the DIR bit in the UEPSTAX register. • If the data stage consists of INs, the firmware has to set the DIR bit in the UEPSTAX register before writing into the FIFO and sending the data by setting to 1 the TXRDY bit in the UEPSTAX register. The IN transaction is complete when the TXCMPL has been set by the hardware. The firmware should clear the TXCMPL bit before any other transaction. • If the data stage consists of OUTs, the firmware has to leave the DIR bit at 0. The RXOUTB0 bit is set by hardware when a new valid packet has been received on the endpoint. The firmware must read the data stored into the FIFO and then clear the RXOUTB0 bit to reset the FIFO and to allow the next transaction. To send a STALL handshake, see “STALL Handshake” on page 92. 14.5.3 Status Stage The DIR bit in the UEPSTAX register should be reset at 0 for IN and OUT status stage. The status stage management is similar to Bulk management. 14.6 14.6.1 • For a Control Write transaction or a No-Data Control transaction, the status stage consists of a IN Zero Length Packet (see “Bulk/Interrupt IN Transactions in Standard Mode” on page 88). To send a STALL handshake, see “STALL Handshake” on page 92. • For a Control Read transaction, the status stage consists of a OUT Zero Length Packet (see “Bulk/Interrupt OUT Transactions in Standard Mode” on page 86). Isochronous Transactions Isochronous OUT Transactions in Standard Mode An endpoint should be first enabled and configured before being able to receive Isochronous packets. When an OUT packet is received on an endpoint, the RXOUTB0 bit is set by the USB controller. This triggers an interrupt if enabled. The firmware has to select the corre Bulk-outsponding endpoint, store the number of data Bytes by reading the UBYCTX register. If the received packet is 90 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C a ZLP (Zero Length Packet), the UBYCTX register value is equal to 0 and no data has to be read. The STLCRC bit in the UEPSTAX register is set by the USB controller if the packet stored in FIFO has a corrupted CRC. This bit is updated after each new packet receipt. When all the endpoint FIFO Bytes have been read, the firmware should clear the RXOUTB0 bit to allow the USB controller to store the next OUT packet data into the endpoint FIFO. Until the RXOUTB0 bit has been cleared by the firmware, the data sent by the Host at each OUT transaction will be lost. If the RXOUTB0 bit is cleared while the Host is sending data, the USB controller will store only the remaining Bytes into the FIFO. If the Host sends more Bytes than supported by the endpoint FIFO, the overflow data won’t be stored, but the USB controller will consider that the packet is valid if the CRC is correct. 14.6.2 Isochronous OUT Transactions in Ping-pong Mode An endpoint should be first enabled and configured before being able to receive Isochronous packets. When a OUT packet is received on the endpoint bank 0, the RXOUTB0 bit is set by the USB controller. This triggers an interrupt if enabled. The firmware has to select the corresponding endpoint, store the number of data Bytes by reading the UBYCTX register. If the received packet is a ZLP (Zero Length Packet), the UBYCTX register value is equal to 0 and no data has to be read. The STLCRC bit in the UEPSTAX register is set by the USB controller if the packet stored in FIFO has a corrupted CRC. This bit is updated after each new packet receipt. When all the endpoint FIFO Bytes have been read, the firmware should clear the RXOUB0 bit to allow the USB controller to store the next OUT packet data into the endpoint FIFO bank 0. This action switches the endpoint bank 0 and 1. Until the RXOUTB0 bit has been cleared by the firmware, the data sent by the Host on the bank 0 endpoint FIFO will be lost. If the RXOUTB0 bit is cleared while the Host is sending data on the endpoint bank 0, the USB controller will store only the remaining Bytes into the FIFO. When a new OUT packet is received on the endpoint bank 1, the RXOUTB1 bit is set by the USB controller. This triggers an interrupt if enabled. The firmware empties the bank 1 endpoint FIFO before clearing the RXOUTB1 bit. Until the RXOUTB1 bit has been cleared by the firmware, the data sent by the Host on the bank 1 endpoint FIFO will be lost. The RXOUTB0 and RXOUTB1 bits are alternatively set by the USB controller at each new packet receipt. The firmware has to clear one of these 2 bits after having read all the data FIFO to allow a new packet to be stored in the corresponding bank. If the Host sends more Bytes than supported by the endpoint FIFO, the overflow data won’t be stored, but the USB controller will consider that the packet is valid if the CRC is correct. 14.6.3 Isochronous IN Transactions in Standard Mode An endpoint should be first enabled and configured before being able to send Isochronous packets. The firmware should fill the FIFO with the data to be sent and set the TXRDY bit in the UEPSTAX register to allow the USB controller to send the data stored in FIFO at the next IN request concerning this endpoint. 91 4109J–8051–10/06 If the TXRDY bit is not set when the IN request occurs, nothing will be sent by the USB controller. When the IN packet has been sent, the TXCMPL bit in the UEPSTAX register is set by the USB controller. This triggers a USB interrupt if enabled. The firmware should clear the TXCMPL bit before filling the endpoint FIFO with new data. The firmware should never write more Bytes than supported by the endpoint FIFO 14.6.4 Isochronous IN Transactions in Ping-pong Mode An endpoint should be first enabled and configured before being able to send Isochronous packets. The firmware should fill the FIFO bank 0 with the data to be sent and set the TXRDY bit in the UEPSTAX register to allow the USB controller to send the data stored in FIFO at the next IN request concerning the endpoint. The FIFO banks are automatically switched, and the firmware can immediately write into the endpoint FIFO bank 1. If the TXRDY bit is not set when the IN request occurs, nothing will be sent by the USB controller. When the IN packet concerning the bank 0 has been sent, the TXCMPL bit is set by the USB controller. This triggers a USB interrupt if enabled. The firmware should clear the TXCMPL bit before filling the endpoint FIFO bank 0 with new data. The FIFO banks are then automatically switched. When the IN packet concerning the bank 1 has been sent, the TXCMPL bit is set by the USB controller. This triggers a USB interrupt if enabled. The firmware should clear the TXCMPL bit before filling the endpoint FIFO bank 1 with new data. The bank switch is performed by the USB controller each time the TXRDY bit is set by the firmware. Until the TXRDY bit has been set by the firmware for an endpoint bank, the USB controller won’t send anything at each IN requests concerning this bank. The firmware should never write more Bytes than supported by the endpoint FIFO. 14.7 14.7.1 Miscellaneous USB Reset The EORINT bit in the USBINT register is set by hardware when a End Of Reset has been detected on the USB bus. This triggers a USB interrupt if enabled. The USB controller is still enabled, but all the USB registers are reset by hardware. The firmware should clear the EORINT bit to allow the next USB reset detection. 14.7.2 STALL Handshake This function is only available for Control, Bulk, and Interrupt endpoints. The firmware has to set the STALLRQ bit in the UEPSTAX register to send a STALL handshake at the next request of the Host on the endpoint selected with the UEPNUM register. The RXSETUP, TXRDY, TXCMPL, RXOUTB0 and RXOUTB1 bits must be first resseted to 0. The bit STLCRC is set at 1 by the USB controller when a STALL has been sent. This triggers an interrupt if enabled. The firmware should clear the STALLRQ and STLCRC bits after each STALL sent. The STALLRQ bit is cleared automatically by hardware when a valid SETUP PID is received on a CONTROL type endpoint. 92 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Important note: when a Clear Halt Feature occurs for an endpoint, the firmware should reset this endpoint using the UEPRST resgister in order to reset the data toggle management. 14.7.3 Start of Frame Detection The SOFINT bit in the USBINT register is set when the USB controller detects a Start Of Frame PID. This triggers an interrupt if enabled. The firmware should clear the SOFINT bit to allow the next Start of Frame detection. 14.7.4 Frame Number When receiving a Start Of Frame, the frame number is automatically stored in the UFNUML and UFNUMH registers. The CRCOK and CRCERR bits indicate if the CRC of the last Start Of Frame is valid (CRCOK set at 1) or corrupted (CRCERR set at 1). The UFNUML and UFNUMH registers are automatically updated when receiving a new Start of Frame. 14.7.5 Data Toggle Bit The Data Toggle bit is set by hardware when a DATA0 packet is received and accepted by the USB controller and cleared by hardware when a DATA1 packet is received and accepted by the USB controller. This bit is reset when the firmware resets the endpoint FIFO using the UEPRST register. For Control endpoints, each SETUP transaction starts with a DATA0 and data toggling is then used as for Bulk endpoints until the end of the Data stage (for a control write transfer). The Status stage completes the data transfer with a DATA1 (for a control read transfer). For Isochronous endpoints, the device firmware should ignore the data-toggle. 14.8 14.8.1 Suspend/Resume Management Suspend The Suspend state can be detected by the USB controller if all the clocks are enabled and if the USB controller is enabled. The bit SPINT is set by hardware when an idle state is detected for more than 3 ms. This triggers a USB interrupt if enabled. In order to reduce current consumption, the firmware can put the USB PAD in idle mode, stop the clocks and put the C51 in Idle or Power-down mode. The Resume detection is still active. The USB PAD is put in idle mode when the firmware clear the SPINT bit. In order to avoid a new suspend detection 3ms later, the firmware has to disable the USB clock input using the SUSPCLK bit in the USBCON Register. The USB PAD automatically exits of idle mode when a wakeup event is detected. The stop of the 48 MHz clock from the PLL should be done in the following order: 1. Disable of the 48 MHz clock input of the USB controller by setting to 1 the SUSPCLK bit in the USBCON register. 2. Disable the PLL by clearing the PLLEN bit in the PLLCON register. 14.8.2 Resume When the USB controller is in Suspend state, the Resume detection is active even if all the clocks are disabled and if the C51 is in Idle or Power-down mode. The WUPCPU bit is set by hardware when a non-idle state occurs on the USB bus. This triggers an interrupt if enabled. This interrupt wakes up the CPU from its Idle or Power-down state and the interrupt function is then executed. The firmware will first enable the 48 MHz generation and then reset to 0 the SUSPCLK bit in the USBCON register if needed. 93 4109J–8051–10/06 The firmware has to clear the SPINT bit in the USBINT register before any other USB operation in order to wake up the USB controller from its Suspend mode. The USB controller is then re-activated. Figure 14-13. Example of a Suspend/Resume Management USB Controller Init SPINT Detection of a SUSPEND State Clear SPINT Set SUSPCLK Disable PLL microcontroller in Power-down WUPCPU Detection of a RESUME State Enable PLL Clear SUSPCLK Clear WUPCPU Bit 14.8.3 Upstream Resume A USB device can be allowed by the Host to send an upstream resume for Remote Wake-up purpose. When the USB controller receives the SET_FEATURE request: DEVICE_REMOTE_WAKEUP, the firmware should set to 1 the RMWUPE bit in the USBCON register to enable this functionality. RMWUPE value should be 0 in the other cases. If the device is in SUSPEND mode, the USB controller can send an upstream resume by clearing first the SPINT bit in the USBINT register and by setting then to 1 the SDRMWUP bit in the USBCON register. The USB controller sets to 1 the UPRSM bit in the USBCON register. All clocks must be enabled first. The Remote Wake is sent only if the USB bus was in Suspend state for at least 5ms. When the upstream resume is completed, the UPRSM bit is reset to 0 by hardware. The firmware should then clear the SDRMWUP bit. 94 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 14-14. Example of REMOTE WAKEUP Management USB Controller Init SET_FEATURE: DEVICE_REMOTE_WAKEUP Set RMWUPE SPINT Detection of a SUSPEND state Suspend Management need USB resume enable clocks Clear SPINT UPRSM = 1 Set SDMWUP UPRSM upstream RESUME sent Clear SDRMWUP 14.9 14.9.1 USB Interrupt System Interrupt System Priorities Figure 14-15. USB Interrupt Control System D+ D- 00 01 10 11 USB Controller EUSB EA IE1.6 IE0.7 Interrupt Enable IPH/L Priority Enable Lowest Priority Interrupts 95 4109J–8051–10/06 Table 1. Priority Levels 14.9.2 IPHUSB IPLUSB USB Priority Level 0 0 0..................Lowest 0 1 1 1 0 2 1 1 3..................Highest USB Interrupt Control System As shown in Figure 14-16, many events can produce a USB interrupt: 96 • TXCMPL: Transmitted In Data (Table 86 on page 101). This bit is set by hardware when the Host accept a In packet. • RXOUTB0: Received Out Data Bank 0 (Table 86 on page 101). This bit is set by hardware when an Out packet is accepted by the endpoint and stored in bank 0. • RXOUTB1: Received Out Data Bank 1 (only for Ping-pong endpoints) (Table 86 on page 101). This bit is set by hardware when an Out packet is accepted by the endpoint and stored in bank 1. • RXSETUP: Received Setup (Table 86 on page 101). This bit is set by hardware when an SETUP packet is accepted by the endpoint. • STLCRC: STALLED (only for Control, Bulk and Interrupt endpoints) (Table 86 on page 101). This bit is set by hardware when a STALL handshake has been sent as requested by STALLRQ, and is reset by hardware when a SETUP packet is received. • SOFINT: Start of Frame Interrupt (Table 82 on page 99). This bit is set by hardware when a USB start of frame packet has been received. • WUPCPU: Wake-Up CPU Interrupt (Table 82 on page 99). This bit is set by hardware when a USB resume is detected on the USB bus, after a SUSPEND state. • SPINT: Suspend Interrupt (Table 82 on page 99). This bit is set by hardware when a USB suspend is detected on the USB bus. AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 14-16. USB Interrupt Control Block Diagram Endpoint X (X = 0..2) TXCMP UEPSTAX.0 RXOUTB0 UEPSTAX.1 RXOUTB1 EPXINT UEPSTAX.6 UEPINT.X RXSETUP EPXIE UEPSTAX.2 UEPIEN.X STLCRC UEPSTAX.3 NAKOUT UEPCONX.5 NAKIN UEPCONX.4 NAKIEN UEPCONX.6 WUPCPU EUSB USBINT.5 IE1.6 EWUPCPU USBIEN.5 EORINT USBINT.4 EEORINT USBIEN.4 SOFINT USBINT.3 ESOFINT USBIEN.3 SPINT USBINT.0 ESPINT USBIEN.0 14.10 Registers Table 80. USBCON Register USBCON (S:BCh) – USB Global Control Register 7 6 5 4 3 2 1 0 USBE SUSPCLK SDRMWUP - UPRSM RMWUPE CONFG FADDEN 97 4109J–8051–10/06 Bit Number Bit Mnemonic Description 7 USBE USB Enable Bit Set this bit to enable the USB controller. Clear this bit to disable and reset the USB controller, to disable the USB transceiver an to disable the USB controllor clock inputs. 6 SUSPCLK Suspend USB Clock Bit Set to disable the 48 MHz clock input (Resume Detection is still active). Clear to enable the 48 MHz clock input. 5 Send Remote Wake-Up Bit Set to force an external interrupt on the USB controller for Remote Wake UP purpose. SDRMWUP An upstream resume is send only if the bit RMWUPE is set, all USB clocks are enabled AND the USB bus was in SUSPEND state for at least 5 ms. See UPRSM below. Cleared by software. 4 - 3 UPRSM 2 RMWUPE Reserved The value read from this bit is always 0. Do not set this bit. Upstream Resume Bit (read only) Set by hardware when SDRMWUP has been set and if RMWUPE is enabled. Cleared by hardware after the upstream resume has been sent. Remote Wake-Up Enable Bit Set to enabled request an upstream resume signaling to the host. Clear after the upstream resume has been indicated by RSMINPR. Note: Do not set this bit if the host has not set the DEVICE_REMOTE_WAKEUP feature for the device. 1 0 CONFG Configuration Bit This bit should be set by the device firmware after a SET_CONFIGURATION request with a non-zero value has been correctly processed. It should be cleared by the device firmware when a SET_CONFIGURATION request with a zero value is received. It is cleared by hardware on hardware reset or when an USB reset is detected on the bus (SE0 state for at least 32 Full Speed bit times: typically 2.7 μs). FADDEN Function Address Enable Bit This bit should be set by the device firmware after a successful status phase of a SET_ADDRESS transaction. It should not be cleared afterwards by the device firmware. It is cleared by hardware on hardware reset or when an USB reset is received (see above). When this bit is cleared, the default function address is used (0). Reset Value = 0000 0000b Table 81. USBADDR Register USBADDR (S:C6h) – USB Address Register 98 7 6 5 4 3 2 1 0 FEN UADD6 UADD5 UADD4 UADD3 UADD2 UADD1 UADD0 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Bit Number 7 6-0 Bit Mnemonic Description FEN Function Enable Bit Set to enable the function. The device firmware should set this bit after it has received a USB reset and participate in the following configuration process with the default address (FEN is reset to 0). Cleared by hardware at power-up, should not be cleared by the device firmware once set. UADD6:0 USB Address Bits This field contains the default address (0) after power-up or USB bus reset. It should be written with the value set by a SET_ADDRESS request received by the device firmware. Reset Value = 0000 0000b Table 82. USBINT Register USBINT (S:BDh) – USB Global Interrupt Register 7 6 5 4 3 2 1 0 - - WUPCPU EORINT SOFINT - - SPINT Bit Number 7-6 Bit Mnemonic Description - Reserved The value read from these bits is always 0. Do not set these bits. WUPCPU Wake Up CPU Interrupt Flag Set by hardware when the USB controller is in SUSPEND state and is reactivated by a non-idle signal from USB line (not by an upstream resume). This triggers a USB interrupt when EWUPCPU is set in the USBIEN. Cleared by software after re-enabling all USB clocks. EORINT End of Reset Interrupt Flag Set by hardware when a End of Reset has been detected by the USB controller. This triggers a USB interrupt when EEORINT is set in USBIEN. Cleared by software. 3 SOFINT Start of Frame Interrupt Flag Set by hardware when an USB Start of Frame packet (SOF) has been properly received. This triggers a USB interrupt when ESOFINT is set in USBIEN. Cleared by software. 2-1 - 5 4 0 SPINT Reserved The value read from these bits is always 0. Do not set these bits. Suspend Interrupt Flag Set by hardware when a USB Suspend (Idle bus for three frame periods: a J state for 3 ms) is detected. This triggers a USB interrupt when ESPINT is set in USBIEN. Cleared by software. Reset Value = 0000 0000b Table 83. USBIEN Register USBIEN (S:BEh) – USB Global Interrupt Enable Register 7 6 5 4 3 2 1 0 - - EWUPCPU EEORINT ESOFINT - - ESPINT 99 4109J–8051–10/06 Bit Number 7-6 5 Bit Mnemonic Description - Reserved The value read from these bits is always 0. Do not set these bits. Wake Up CPU Interrupt Enable Bit EWUPCPU Set to enable the Wake Up CPU interrupt. Clear to disable the Wake Up CPU interrupt. 4 EEOFINT End Of Reset Interrupt Enable Bit Set to enable the End Of Reset interrupt. This bit is set after reset. Clear to disable End Of Reset interrupt. 3 ESOFINT Start Of Frame Interrupt Enable Bit Set to enable the SOF interrupt. Clear to disable the SOF interrupt. 2-1 - 0 ESPINT Reserved The value read from these bits is always 0. Do not set these bits. Suspend Interrupt Enable Bit Set to enable Suspend interrupt. Clear to disable Suspend interrupt. Reset Value = 0001 0000b Table 84. UEPNUM Register UEPNUM (S:C7h) – USB Endpoint Number 7 6 5 4 3 2 1 0 - - - - - - EPNUM1 EPNUM0 Bit Number 7-2 1-0 Bit Mnemonic Description - Reserved The value read from these bits is always 0. Do not set these bits. Endpoint Number Bits EPNUM1:0 Set this field with the number of the endpoint which should be accessed when reading or writing to registers UEPSTAX, UEPDATX, UBYCTX or UEPCONX. Reset Value = 0000 0000b Table 85. UEPCONX Register UEPCONX (S:D4h) – USB Endpoint X Control Register (X = EPNUM set in UEPNUM) 100 7 6 5 4 3 2 1 0 EPEN NAKIEN NAKOUT NAKIN DTGL EPDIR EPTYPE1 EPTYPE0 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Bit Number Bit Mnemonic Description Endpoint Enable Bit Set to enable the endpoint according to the device configuration. Endpoint 0 should always be enabled after a hardware or USB bus reset and participate in the device configuration. Clear to disable the endpoint according to the device configuration. 7 EPEN 6 NAKIEN NAK Interrupt enable Set this bit to enable NAK IN or NAK OUT interrupt. Clear this bit to disable NAK IN or NAK OUT Interrupt. NAKOUT NAK OUT received This bit is set by hardware when an NAK handshake has been sent in response of a OUT request from the Host. This triggers a USB interrupt when NAKIEN is set. This bit should be cleared by software. 4 NAKIN NAK IN received This bit is set by hardware when an NAK handshake has been sent in response of a IN request from the Host. This triggers a USB interrupt when NAKIEN is set. This bit should be cleared by software. 3 DTGL Data Toggle Status Bit (Read-only) Set by hardware when a DATA1 packet is received. Cleared by hardware when a DATA0 packet is received. EPDIR Endpoint Direction Bit Set to configure IN direction for Bulk, Interrupt and Isochronous endpoints. Clear to configure OUT direction for Bulk, Interrupt and Isochronous endpoints. This bit has no effect for Control endpoints. EPTYPE1: 0 Endpoint Type Bits Set this field according to the endpoint configuration (Endpoint 0 should always be configured as Control): 00 Control endpoint 01 Isochronous endpoint 10 Bulk endpoint 11 Interrupt endpoint 5 2 1-0 Reset Value = 1000 0000b Table 86. UEPSTAX Register UEPSTAX (S:CEh) – USB Endpoint X Status and Control Register (X = EPNUM set in UEPNUM) 7 6 5 4 3 2 1 0 DIR RXOUTB1 STALLRQ TXRDY STLCRC RXSETUP RXOUTB0 TXCMP 101 4109J–8051–10/06 Bit Number Bit Mnemonic Description Control Endpoint Direction Bit This bit is relevant only if the endpoint is configured in Control type. Set for the data stage. Clear otherwise. 7 6 102 DIR RXOUTB1 Note: This bit should be configured on RXSETUP interrupt before any other bit is changed. This also determines the status phase (IN for a control write and OUT for a control read). This bit should be cleared for status stage of a Control Out transaction. Received OUT Data Bank 1 for Endpoints 1 and 2 (Ping-pong mode) This bit is set by hardware after a new packet has been stored in the endpoint FIFO data bank 1 (only in Ping-pong mode). Then, the endpoint interrupt is triggered if enabled and all the following OUT packets to the endpoint bank 1 are rejected (NAK’ed) until this bit has been cleared, excepted for Isochronous Endpoints. This bit should be cleared by the device firmware after reading the OUT data from the endpoint FIFO. AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Bit Number 5 4 3 2 1 0 Bit Mnemonic Description STALLRQ Stall Handshake Request Bit Set to send a STALL answer to the host for the next handshake. Clear otherwise. TXRDY TX Packet Ready Control Bit Set after a packet has been written into the endpoint FIFO for IN data transfers. Data should be written into the endpoint FIFO only after this bit has been cleared. Set this bit without writing data to the endpoint FIFO to send a Zero Length Packet, which is generally recommended and may be required to terminate a transfer when the length of the last data packet is equal to MaxPacketSize (e.g. for control read transfers). Cleared by hardware, as soon as the packet has been sent for Isochronous endpoints, or after the host has acknowledged the packet for Control, Bulk and Interrupt endpoints. STLCRC Stall Sent Interrupt Flag/CRC Error Interrupt Flag For Control, Bulk and Interrupt Endpoints: Set by hardware after a STALL handshake has been sent as requested by STALLRQ. Then, the endpoint interrupt is triggered if enabled in UEPIEN. Cleared by hardware when a SETUP packet is received (see RXSETUP). For Isochronous Endpoints: Set by hardware if the last data received is corrupted (CRC error on data). Then, the endpoint interrupt is triggered if enabled in UEPIEN. Cleared by hardware when a non corrupted data is received. RXSETUP Received SETUP Interrupt Flag Set by hardware when a valid SETUP packet has been received from the host. Then, all the other bits of the register are cleared by hardware and the endpoint interrupt is triggered if enabled in UEPIEN. Clear by software after reading the SETUP data from the endpoint FIFO. RXOUTB0 Received OUT Data Bank 0 (see also RXOUTB1 bit for Ping-pong Endpoints) This bit is set by hardware after a new packet has been stored in the endpoint FIFO data bank 0. Then, the endpoint interrupt is triggered if enabled and all the following OUT packets to the endpoint bank 0 are rejected (NAK’ed) until this bit has been cleared, excepted for Isochronous Endpoints. However, for control endpoints, an early SETUP transaction may overwrite the content of the endpoint FIFO, even if its Data packet is received while this bit is set. This bit should be cleared by the device firmware after reading the OUT data from the endpoint FIFO. TXCMP Transmitted IN Data Complete Interrupt Flag Set by hardware after an IN packet has been transmitted for Isochronous endpoints and after it has been accepted (ACK’ed) by the host for Control, Bulk and Interrupt endpoints. Then, the endpoint interrupt is triggered if enabled in UEPIEN. Clear by software before setting again TXRDY. Reset Value = 0000 0000b Table 87. UEPRST Register UEPRST (S:D5h) – USB Endpoint FIFO Reset Register 7 6 5 4 3 2 1 0 - - - - - EP2RST EP1RST EP0RST 103 4109J–8051–10/06 Bit Number Bit Mnemonic Description Reserved The value read from these bits is always 0. Do not set these bits. 7-3 - 2 EP2RST Endpoint 2 FIFO Reset Set and clear to reset the endpoint 2 FIFO prior to any other operation, upon hardware reset or when an USB bus reset has been received. 1 EP1RST Endpoint 1 FIFO Reset Set and clear to reset the endpoint 1 FIFO prior to any other operation, upon hardware reset or when an USB bus reset has been received. 0 EP0RST Endpoint 0 FIFO Reset Set and clear to reset the endpoint 0 FIFO prior to any other operation, upon hardware reset or when an USB bus reset has been received. Reset Value = 0000 0000b Table 88. UEPIEN Register UEPIEN (S:C2h) – USB Endpoint Interrupt Enable Register 7 6 5 4 3 2 1 0 - - - - - EP2INTE EP1INTE EP0INTE Bit Number Bit Mnemonic Description Reserved The value read from these bits is always 0. Do not set these bits. 7-3 - 2 EP2INTE Endpoint 2 Interrupt Enable Bit Set to enable the interrupts for endpoint 2. Clear this bit to disable the interrupts for endpoint 2. 1 EP1INTE Endpoint 1 Interrupt Enable Bit Set to enable the interrupts for the endpoint 1. Clear to disable the interrupts for the endpoint 1. 0 EP0INTE Endpoint 0 Interrupt Enable Bit Set to enable the interrupts for the endpoint 0. Clear to disable the interrupts for the endpoint 0. Reset Value = 0000 0000b Table 89. UEPINT Register UEPINT (S:F8h Read-only) – USB Endpoint Interrupt Register 104 7 6 5 4 3 2 1 0 - - - - - EP2INT EP1INT EP0INT AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Bit Number 7-3 2 Bit Mnemonic Description - EP2INT Reserved The value read from these bits is always 0. Do not set these bits. Endpoint 2 Interrupt Flag This bit is set by hardware when an endpoint interrupt source has been detected on the endpoint 2. The endpoint interrupt sources are in the UEPSTAX register and can be: TXCMP, RXOUTB0, RXOUTB1, RXSETUP or STLCRC. A USB interrupt is triggered when the EP2IE bit in the UEPIEN register is set. This bit is cleared by hardware when all the endpoint interrupt sources are cleared. 1 EP1INT Endpoint 1 Interrupt Flag This bit is set by hardware when an endpoint interrupt source has been detected on the endpoint 1. The endpoint interrupt sources are in the UEPSTAX register and can be: TXCMP, RXOUTB0, RXOUTB1, RXSETUP or STLCRC. A USB interrupt is triggered when the EP1IE bit in the UEPIEN register is set. This bit is cleared by hardware when all the endpoint interrupt sources are cleared. 0 EP0INT Endpoint 0 Interrupt Flag This bit is set by hardware when an endpoint interrupt source has been detected on the endpoint 0. The endpoint interrupt sources are in the UEPSTAX register and can be: TXCMP, RXOUTB0, RXOUTB1, RXSETUP or STLCRC. A USB interrupt is triggered when the EP0IE bit in the UEPIEN register is set. This bit is cleared by hardware when all the endpoint interrupt sources are cleared. Reset Value = 0000 0000b Table 90. UEPDATX Register UEPDATX (S:CFh) – USB Endpoint X FIFO Data Register (X = EPNUM set in UEPNUM) 7 6 5 4 3 2 1 0 FDAT7 FDAT6 FDAT5 FDAT4 FDAT3 FDAT2 FDAT1 FDAT0 Bit Number 7-0 Bit Mnemonic Description FDAT7:0 Endpoint X FIFO Data Data Byte to be written to FIFO or data Byte to be read from the FIFO, for the Endpoint X (see EPNUM). Reset Value = XXh Table 91. UBYCTX Register UBYCTX (S:E2h) – USB Endpoint X Byte Count Register (X = EPNUM set in UEPNUM) 7 6 5 4 3 2 1 0 - BYCT6 BYCT5 BYCT4 BYCT3 BYCT2 BYCT1 BYCT0 105 4109J–8051–10/06 Bit Number Bit Mnemonic Description 7 - 6-0 BYCT7:0 Reserved The value read from this bits is always 0. Do not set this bit. Byte Count Byte count of a received data packet. This Byte count is equal to the number of data Bytes received after the Data PID. Reset Value = 0000 0000b Table 92. UFNUML Register UFNUML (S:BAh, Read-only) – USB Frame Number Low Register 7 6 5 4 3 2 1 0 FNUM7 FNUM6 FNUM5 FNUM4 FNUM3 FNUM2 FNUM1 FNUM0 Bit Number 7-0 Bit Mnemonic Description FNUM7:0 Frame Number Lower 8 bits of the 11-bit Frame Number. Reset Value = 00h Table 93. UFNUMH Register UFNUMH (S:BBh, Read-only) – USB Frame Number High Register 7 6 5 4 3 2 1 0 - - CRCOK CRCERR - FNUM10 FNUM9 FNUM8 Bit Number 7-3 5 Bit Mnemonic Description - CRCOK Reserved The value read from these bits is always 0. Do not set these bits. Frame Number CRC OK Bit Set by hardware after a non corrupted Frame Number in Start of Frame Packet is received. Updated after every Start Of Frame packet reception. Note: The Start Of Frame interrupt is generated just after the PID receipt. 4 CRCERR Frame Number CRC Error Bit Set by hardware after a corrupted Frame Number in Start of Frame Packet is received. Updated after every Start Of Frame packet reception. Note: The Start Of Frame interrupt is generated just after the PID receipt. 3 2-0 - Reserved The value read from this bits is always 0. Do not set this bit. Frame Number FNUM10:8 Upper 3 bits of the 11-bit Frame Number. It is provided in the last received SOF packet. FNUM does not change if a corrupted SOF is received. Reset Value = 00h 106 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Table 94. USBCLK Register USBCLK (S:EAh) – USB Clock Divider Register 7 6 5 4 3 2 1 0 - - - - - - USBCD1 USBCD0 Bit Number Bit Mnemonic Description 7-2 - 1-0 USBCD1:0 Reserved The value read from these bits is always 0. Do not set these bits. USB Controller Clock Divider 2-bit divider for USB controller clock generation. Reset Value = 0000 0000b 107 4109J–8051–10/06 15. MultiMedia Card Controller The AT8xC51SND1C implements a MultiMedia Card (MMC) controller. The MMC is used to store MP3 encoded audio files in removable Flash memory cards that can be easily plugged or removed from the application. 15.1 Card Concept The basic MultiMedia Card concept is based on transferring data via a minimum number of signals. 15.1.1 Card Signals The communication signals are: 15.1.2 • CLK: with each cycle of this signal a one bit transfer on the command and data lines is done. The frequency may vary from zero to the maximum clock frequency. • CMD: is a bi-directional command channel used for card initialization and data transfer commands. The CMD signal has 2 operation modes: open-drain for initialization mode and push-pull for fast command transfer. Commands are sent from the MultiMedia Card bus master to the card and responses from the cards to the host. • DAT: is a bi-directional data channel. The DAT signal operates in push-pull mode. Only one card or the host is driving this signal at a time. Card Registers Within the card interface five registers are defined: OCR, CID, CSD, RCA and DSR. These can be accessed only by the corresponding commands. The 32-bit Operation Conditions Register (OCR) stores the VDD voltage profile of the card. The register is optional and can be read only. The 128-bit wide CID register carries the card identification information (Card ID) used during the card identification procedure. The 128-bit wide Card-Specific Data register (CSD) provides information on how to access the card contents. The CSD defines the data format, error correction type, maximum data access time, data transfer speed, and whether the DSR register can be used. The 16-bit Relative Card Address register (RCA) carries the card address assigned by the host during the card identification. This address is used for the addressed host-card communication after the card identification procedure. The 16-bit Driver Stage Register (DSR) can be optionally used to improve the bus performance for extended operating conditions (depending on parameters like bus length, transfer rate or number of cards). 15.2 Bus Concept The MultiMedia Card bus is designed to connect either solid-state mass-storage memory or I/Odevices in a card format to multimedia applications. The bus implementation allows the coverage of application fields from low-cost systems to systems with a fast data transfer rate. It is a single master bus with a variable number of slaves. The MultiMedia Card bus master is the bus controller and each slave is either a single mass storage card (with possibly different technologies such as ROM, OTP, Flash etc.) or an I/O-card with its own controlling unit (on card) to perform the data transfer. The MultiMedia Card bus also includes power connections to supply the cards. 108 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C The bus communication uses a special protocol (MultiMedia Card bus protocol) which is applicable for all devices. Therefore, the payload data transfer between the host and the cards can be bi-directional. 15.2.1 Bus Lines The MultiMedia Card bus architecture requires all cards to be connected to the same set of lines. No card has an individual connection to the host or other devices, which reduces the connection costs of the MultiMedia Card system. The bus lines can be divided into three groups: 15.2.2 • Power supply: VSS1 and VSS2, VDD – used to supply the cards. • Data transfer: MCMD, MDAT – used for bi-directional communication. • Clock: MCLK – used to synchronize data transfer across the bus. Bus Protocol After a power-on reset, the host must initialize the cards by a special message-based MultiMedia Card bus protocol. Each message is represented by one of the following tokens: • Command: a command is a token which starts an operation. A command is transferred serially from the host to the card on the MCMD line. • Response: a response is a token which is sent from an addressed card (or all connected cards) to the host as an answer to a previously received command. It is transferred serially on the MCMD line. • Data: data can be transferred from the card to the host or vice-versa. Data is transferred serially on the MDAT line. Card addressing is implemented using a session address assigned during the initialization phase, by the bus controller to all currently connected cards. Individual cards are identified by their CID number. This method requires that every card will have an unique CID number. To ensure uniqueness of CIDs the CID register contains 24 bits (MID and OID fields) which are defined by the MMCA. Every card manufacturers is required to apply for an unique MID (and optionally OID) number. MultiMedia Card bus data transfers are composed of these tokens. One data transfer is a bus operation. There are different types of operations. Addressed operations always contain a command and a response token. In addition, some operations have a data token, the others transfer their information directly within the command or response structure. In this case no data token is present in an operation. The bits on the MDAT and the MCMD lines are transferred synchronous to the host clock. 2 types of data transfer commands are defined: • Sequential commands: These commands initiate a continuous data stream, they are terminated only when a stop command follows on the MCMD line. This mode reduces the command overhead to an absolute minimum. • Block-oriented commands: These commands send a data block succeeded by CRC bits. Both read and write operations allow either single or multiple block transmission. A multiple block transmission is terminated when a stop command follows on the MCMD line similarly to the stream read. Figure 15-1 through Figure 15-5 show the different types of operations, on these figures, grayed tokens are from host to card(s) while white tokens are from card(s) to host. 109 4109J–8051–10/06 Figure 15-1. Sequential Read Operation Stop Command MCMD Command Response Command MDAT Response Data Stream Data Transfer Operation Data Stop Operation Figure 15-2. (Multiple) Block Read Operation Stop Command MCMD Command MDAT Response Command Response Data Block CRC Data Block CRC Data Block CRC Block Read Operation Data Stop Operation Multiple Block Read Operation As shown in Figure 15-3 and Figure 15-4 the data write operation uses a simple busy signalling of the write operation duration on the data line (MDAT). Figure 15-3. Sequential Write Operation Stop Command MCMD Command Response Command MDAT Data Stream Data Transfer Operation Response Busy Data Stop Operation Figure 15-4. Multiple Block Write Operation Stop Command MCMD Command Response MDAT Command Data Block CRC Status Busy Response Data Block CRC Status Busy Block Write Operation Data Stop Operation Multiple Block Write Operation Figure 15-5. No Response and No Data Operation MCMD Command Command Response MDAT No Response Operation 110 No Data Operation AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 15.2.3 Command Token Format As shown in Figure 15-6, commands have a fixed code length of 48 bits. Each command token is preceded by a Start bit: a low level on MCMD line and succeeded by an End bit: a high level on MCMD line. The command content is preceded by a Transmission bit: a high level on MCMD line for a command token (host to card) and succeeded by a 7 - bit CRC so that transmission errors can be detected and the operation may be repeated. Command content contains the command index and address information or parameters. Figure 15-6. Command Token Format 0 1 Content CRC 1 Total Length = 48 bits Table 95. Command Token Format Bit Position 47 46 45:40 39:8 7:1 0 Width (Bits) 1 1 6 32 7 1 Value ‘0’ ‘1’ - - - ‘1’ Start bit Transmission bit Command Index Argument CRC7 End bit Description 15.2.4 Response Token Format There are five types of response tokens (R1 to R5). As shown in Figure 15-7, responses have a code length of 48 bits or 136 bits. A response token is preceded by a Start bit: a low level on MCMD line and succeeded by an End bit: a high level on MCMD line. The command content is preceded by a Transmission bit: a low level on MCMD line for a response token (card to host) and succeeded (R1,R2,R4,R5) or not (R3) by a 7 - bit CRC. Response content contains mirrored command and status information (R1 response), CID register or CSD register (R2 response), OCR register (R3 response), or RCA register (R4 and R5 response). Figure 15-7. Response Token Format R1, R4, R5 0 0 Content CRC 1 Total Length = 48 bits R3 0 0 Content 1 Total Length = 48 bits R2 0 0 Content = CID or CSD CRC 1 Total Length = 136 bits 111 4109J–8051–10/06 Table 96. R1 Response Format (Normal Response) Bit Position 47 46 45:40 39:8 7:1 0 Width (bits) 1 1 6 32 7 1 Value ‘0’ ‘0’ - - - ‘1’ Start bit Transmission bit Command Index Card Status CRC7 End bit Description Table 97. R2 Response Format (CID and CSD registers) Bit Position 135 134 [133:128] [127:1] 0 Width (bits) 1 1 6 32 1 Value ‘0’ ‘0’ ‘111111’ - ‘1’ Description Start bit Transmission bit Reserved Argument End bit Table 98. R3 Response Format (OCR Register) Bit Position 47 46 [45:40] [39:8] [7:1] 0 Width (bits) 1 1 6 32 7 1 Value ‘0’ ‘0’ ‘111111’ - ‘1111111’ ‘1’ Start bit Transmission bit Reserved OCR register Reserved End bit Description Table 99. R4 Response Format (Fast I/O) Bit Position 47 46 [45:40] [39:8] [7:1] 0 Width (bits) 1 1 6 32 7 1 Value ‘0’ ‘0’ ‘100111’ - - ‘1’ Start bit Transmission bit Command Index Argument CRC7 End bit Description Table 100. R5 Response Format Bit Position 47 46 [45:40] [39:8] [7:1] 0 Width (bits) 1 1 6 32 7 1 Value ‘0’ ‘0’ ‘101000’ - - ‘1’ Start bit Transmission bit Command Index Argument CRC7 End bit Description 15.2.5 Data Packet Format There are 2 types of data packets: stream and block. As shown in Figure 15-8, stream data packets have an indeterminate length while block packets have a fixed length depending on the block length. Each data packet is preceded by a Start bit: a low level on MCMD line and succeeded by an End bit: a high level on MCMD line. Due to the fact that there is no predefined end 112 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C in stream packets, CRC protection is not included in this case. The CRC protection algorithm for block data is a 16-bit CCITT polynomial. Figure 15-8. Data Token Format Sequential Data 0 Block Data 0 Content Content 1 CRC 1 Block Length 15.2.6 Clock Control The MMC bus clock signal can be used by the host to turn the cards into energy saving mode or to control the data flow (to avoid under-run or over-run conditions) on the bus. The host is allowed to lower the clock frequency or shut it down. There are a few restrictions the host must follow: 15.3 • The bus frequency can be changed at any time (under the restrictions of maximum data transfer frequency, defined by the cards, and the identification frequency defined by the specification document). • It is an obvious requirement that the clock must be running for the card to output data or response tokens. After the last MultiMedia Card bus transaction, the host is required, to provide 8 (eight) clock cycles for the card to complete the operation before shutting down the clock. Following is a list of the various bus transactions: • A command with no response. 8 clocks after the host command End bit. • A command with response. 8 clocks after the card command End bit. • A read data transaction. 8 clocks after the End bit of the last data block. • A write data transaction. 8 clocks after the CRC status token. • The host is allowed to shut down the clock of a “busy” card. The card will complete the programming operation regardless of the host clock. However, the host must provide a clock edge for the card to turn off its busy signal. Without a clock edge the card (unless previously disconnected by a deselect command-CMD7) will force the MDAT line down, forever. Description The MMC controller interfaces to the C51 core through the following eight special function registers: MMCON0, MMCON1, MMCON2, the three MMC control registers (see Table 102 to Table 110); MMSTA, the MMC status register (see Table 105); MMINT, the MMC interrupt register (see Table 106); MMMSK, the MMC interrupt mask register (see Table 107); MMCMD, the MMC command register (see Table 108); MMDAT, the MMC data register (see Table 109); and MMCLK, the MMC clock register (see Table 110). As shown in Figure 15-9, the MMC controller is divided in four blocks: the clock generator that handles the MCLK (formally the MMC CLK) output to the card, the command line controller that handles the MCMD (formally the MMC CMD) line traffic to or from the card, the data line controller that handles the MDAT (formally the MMC DAT) line traffic to or from the card, and the interrupt controller that handles the MMC controller interrupt sources. These blocks are detailed in the following sections. 113 4109J–8051–10/06 Figure 15-9. MMC Controller Block Diagram MCLK Clock Generator OSC CLOCK Command Line Controller MCMD MMC Interrupt Request Interrupt Controller Data Line Controller Internal Bus 15.4 MDAT 8 Clock Generator The MMC clock is generated by division of the oscillator clock (FOSC) issued from the Clock Controller block as detailed in Section "Oscillator", page 12. The division factor is given by MMCD7:0 bits in MMCLK register, a value of 0x00 stops the MMC clock. Figure 15-10 shows the MMC clock generator and its output clock calculation formula. Figure 15-10. MMC Clock Generator and Symbol OSC CLOCK Controller Clock OSCclk MMCclk = ----------------------------MMCD + 1 MMCLK MMCEN MMCON2.7 MMCD7:0 MMC Clock MMC CLOCK MMC Clock Symbol As soon as MMCEN bit in MMCON2 is set, the MMC controller receives its system clock. The MMC command and data clock is generated on MCLK output and sent to the command line and data line controllers. Figure 15-11 shows the MMC controller configuration flow. As exposed in Section “Clock Control”, page 113, MMCD7:0 bits can be used to dynamically increase or reduce the MMC clock. Figure 15-11. Configuration Flow MMC Controller Configuration Configure MMC Clock MMCLK = XXh MMCEN = 1 FLOWC = 0 15.5 Command Line Controller As shown in Figure 15-12, the command line controller is divided in 2 channels: the command transmitter channel that handles the command transmission to the card through the MCMD line and the command receiver channel that handles the response reception from the card through the MCMD line. These channels are detailed in the following sections. 114 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 15-12. Command Line Controller Block Diagram TX Pointer 5-Byte FIFO CTPTR MMCMD Write MMCON0.4 Data Converter // -> Serial CRC7 Generator TX COMMAND Line Finished State Machine CFLCK MMINT.5 EOCI MMSTA.0 CMDEN Command Transmitter RX Pointer 17 - Byte FIFO MCMD MMCON1.0 Data Converter Serial -> // MMSTA.2 MMSTA.1 CRC7S RESPFS CRC7 and Format Checker MMCMD Read CRPTR MMCON0.5 RX COMMAND Line Finished State Machine RESPEN Command Receiver 15.5.1 RFMT MMINT.6 EORI CRCDIS MMCON1.1 MMCON0.1 MMCON0.0 Command Transmitter For sending a command to the card, user must load the command index (1 Byte) and argument (4 Bytes) in the command transmit FIFO using the MMCMD register. Before starting transmission by setting and clearing the CMDEN bit in MMCON1 register, user must first configure: • RESPEN bit in MMCON1 register to indicate whether a response is expected or not. • RFMT bit in MMCON0 register to indicate the response size expected. • CRCDIS bit in MMCON0 register to indicate whether the CRC7 included in the response will be computed or not. In order to avoid CRC error, CRCDIS may be set for response that do not include CRC7. Figure 15-13 summarizes the command transmission flow. As soon as command transmission is enabled, the CFLCK flag in MMSTA is set indicating that write to the FIFO is locked. This mechanism is implemented to avoid command overrun. The end of the command transmission is signalled to you by the EOCI flag in MMINT register becoming set. This flag may generate an MMC interrupt request as detailed in Section "Interrupt", page 122. The end of the command transmission also resets the CFLCK flag. User may abort command loading by setting and clearing the CTPTR bit in MMCON0 register which resets the write pointer to the transmit FIFO. 115 4109J–8051–10/06 Figure 15-13. Command Transmission Flow Command Transmission Configure Response RESPEN = X RFMT = X CRCDIS = X Load Command in Buffer MMCMD = index MMCMD = argument Transmit Command CMDEN = 1 CMDEN = 0 15.5.2 Command Receiver The end of the response reception is signalled to you by the EORI flag in MMINT register. This flag may generate an MMC interrupt request as detailed in Section "Interrupt", page 122. When this flag is set, 2 other flags in MMSTA register: RESPFS and CRC7S give a status on the response received. RESPFS indicates if the response format is correct or not: the size is the one expected (48 bits or 136 bits) and a valid End bit has been received, and CRC7S indicates if the CRC7 computation is correct or not. These Flags are cleared when a command is sent to the card and updated when the response has been received. User may abort response reading by setting and clearing the CRPTR bit in MMCON0 register which resets the read pointer to the receive FIFO. According to the MMC specification delay between a command and a response (formally NCR parameter) can not exceed 64 MMC clock periods. To avoid any locking of the MMC controller when card does not send its response (e.g. physically removed from the bus), user must launch a time-out period to exit from such situation. In case of time-out user may reset the command controller and its internal state machine by setting and clearing the CCR bit in MMCON2 register. This time-out may be disarmed when receiving the response. 15.6 Data Line Controller The data line controller is based on a 16-Byte FIFO used both by the data transmitter channel and by the data receiver channel. 116 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 15-14. Data Line Controller Block Diagram MMINT.0 MMINT.2 MMSTA.3 MMSTA.4 F1EI F1FI DATFS CRC16S CRC16 and Format Checker Data Converter Serial -> // 8-Byte TX Pointer FIFO 1 DTPTR MMCON0.6 RX Pointer DRPTR MMCON0.7 15.6.1 16-Byte FIFO MMDAT MCBI CBUSY MMINT.1 MMSTA.5 MDAT Data Converter // -> Serial CRC16 Generator 8-Byte F2EI F2FI MMINT.1 MMINT.3 MMINT.4 DATA Line Finished State Machine FIFO 2 DFMT MBLOCK DATEN MMCON0.2 MMCON0.3 MMCON1.2 DATDIR EOFI BLEN3:0 MMCON1.3 MMCON1.7:4 FIFO Implementation The 16-Byte FIFO is based on a dual 8-Byte FIFOs managed using 2 pointers and four flags indicating the status full and empty of each FIFO. Pointers are not accessible to user but can be reset at any time by setting and clearing DRPTR and DTPTR bits in MMCON0 register. Resetting the pointers is equivalent to abort the writing or reading of data. F1EI and F2EI flags in MMINT register signal when set that respectively FIFO1 and FIFO2 are empty. F1FI and F2FI flags in MMINT register signal when set that respectively FIFO1 and FIFO2 are full. These flags may generate an MMC interrupt request as detailed in Section “Interrupt”. 15.6.2 Data Configuration Before sending or receiving any data, the data line controller must be configured according to the type of the data transfer considered. This is achieved using the Data Format bit: DFMT in MMCON0 register. Clearing DFMT bit enables the data stream format while setting DFMT bit enables the data block format. In data block format, user must also configure the single or multiblock mode by clearing or setting the MBLOCK bit in MMCON0 register and the block length using BLEN3:0 bits in MMCON1 according to Table 101. Figure 15-15 summarizes the data modes configuration flows. Table 101. Block Length Programming BLEN3:0 BLEN = 0000 to 1011 > 1011 Block Length (Byte) Length = 2BLEN: 1 to 2048 Reserved: do not program BLEN3:0 > 1011 117 4109J–8051–10/06 Figure 15-15. Data Controller Configuration Flows 15.6.3 15.6.3.1 Data Stream Configuration Data Single Block Configuration Data Multi-Block Configuration Configure Format DFMT = 0 Configure Format DFMT = 1 MBLOCK = 0 BLEN3:0 = XXXXb Configure Format DFMT = 1 MBLOCK = 1 BLEN3:0 = XXXXb Data Transmitter Configuration For transmitting data to the card user must first configure the data controller in transmission mode by setting the DATDIR bit in MMCON1 register. Figure 15-16 summarizes the data stream transmission flows in both polling and interrupt modes while Figure 15-17 summarizes the data block transmission flows in both polling and interrupt modes, these flows assume that block length is greater than 16 data. 15.6.3.2 Data Loading Data is loaded in the FIFO by writing to MMDAT register. Number of data loaded may vary from 1 to 16 Bytes. Then if necessary (more than 16 Bytes to send) user must wait that one FIFO becomes empty (F1EI or F2EI set) before loading 8 new data. 15.6.3.3 Data Transmission Transmission is enabled by setting and clearing DATEN bit in MMCON1 register. Data is transmitted immediately if the response has already been received, or is delayed after the response reception if its status is correct. In both cases transmission is delayed if a card sends a busy state on the data line until the end of this busy condition. According to the MMC specification, the data transfer from the host to the card may not start sooner than 2 MMC clock periods after the card response was received (formally NWR parameter). To address all card types, this delay can be programmed using DATD1:0 bits in MMCON2 register from 3 MMC clock periods when DATD1:0 bits are cleared to 9 MMC clock periods when DATD1:0 bits are set, by step of 2 MMC clock periods. 15.6.3.4 End of Transmission The end of a data frame (block or stream) transmission is signalled to you by the EOFI flag in MMINT register. This flag may generate an MMC interrupt request as detailed in Section "Interrupt", page 122. In data stream mode, EOFI flag is set, after reception of the End bit. This assumes user has previously sent the STOP command to the card, which is the only way to stop stream transfer. In data block mode, EOFI flag is set, after reception of the CRC status token (see Figure 15-7). 2 other flags in MMSTA register: DATFS and CRC16S report a status on the frame sent. DATFS indicates if the CRC status token format is correct or not, and CRC16S indicates if the card has found the CRC16 of the block correct or not. 15.6.3.5 Busy Status As shown in Figure 15-7 the card uses a busy token during a block write operation. This busy status is reported to you by the CBUSY flag in MMSTA register and by the MCBI flag in MMINT 118 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C which is set every time CBUSY toggles, i.e. when the card enters and exits its busy state. This flag may generate an MMC interrupt request as detailed in Section "Interrupt", page 122. Figure 15-16. Data Stream Transmission Flows Data Stream Transmission Data Stream Initialization Data Stream Transmission ISR FIFOs Filling write 16 data to MMDAT FIFOs Filling write 16 data to MMDAT Start Transmission DATEN = 1 DATEN = 0 Unmask FIFOs Empty F1EM = 0 F2EM = 0 FIFO Empty? F1EI or F2EI = 1? Start Transmission DATEN = 1 DATEN = 0 FIFO Empty? F1EI or F2EI = 1? FIFO Filling write 8 data to MMDAT FIFO Filling write 8 data to MMDAT Mask FIFOs Empty F1EM = 1 F2EM = 1 No More Data To Send? Send STOP Command No More Data To Send? Send STOP Command b. Interrupt mode a. Polling mode 119 4109J–8051–10/06 Figure 15-17. Data Block Transmission Flows Data Block Transmission Data Block Initialization FIFOs Filling write 16 data to MMDAT FIFOs Filling write 16 data to MMDAT Start Transmission DATEN = 1 DATEN = 0 Unmask FIFOs Empty F1EM = 0 F2EM = 0 FIFO Empty? F1EI or F2EI = 1? Start Transmission DATEN = 1 DATEN = 0 FIFO Filling write 8 data to MMDAT No More Data To Send? Data Block Transmission ISR FIFO Empty? F1EI or F2EI = 1? FIFO Filling write 8 data to MMDAT No More Data To Send? Mask FIFOs Empty F1EM = 1 F2EM = 1 b. Interrupt mode a. Polling mode 15.6.4 15.6.4.1 Data Receiver Configuration To receive data from the card you must first configure the data controller in reception mode by clearing the DATDIR bit in MMCON1 register. Figure 15-18 summarizes the data stream reception flows in both polling and interrupt modes while Figure 15-19 summarizes the data block reception flows in both polling and interrupt modes, these flows assume that block length is greater than 16 Bytes. 15.6.4.2 Data Reception The end of a data frame (block or stream) reception is signalled to you by the EOFI flag in MMINT register. This flag may generate an MMC interrupt request as detailed in Section "Interrupt", page 122. When this flag is set, 2 other flags in MMSTA register: DATFS and CRC16S give a status on the frame received. DATFS indicates if the frame format is correct or not: a valid End bit has been received, and CRC16S indicates if the CRC16 computation is correct or not. In case of data stream CRC16S has no meaning and stays cleared. According to the MMC specification data transmission from the card starts after the access time delay (formally NAC parameter) beginning from the End bit of the read command. To avoid any locking of the MMC controller when card does not send its data (e.g. physically removed from the bus), you must launch a time-out period to exit from such situation. In case of time-out you 120 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C may reset the data controller and its internal state machine by setting and clearing the DCR bit in MMCON2 register. This time-out may be disarmed after receiving 8 data (F1FI flag set) or after receiving end of frame (EOFI flag set) in case of block length less than 8 data (1, 2 or 4). 15.6.4.3 Data Reading Data is read from the FIFO by reading to MMDAT register. Each time one FIFO becomes full (F1FI or F2FI set), user is requested to flush this FIFO by reading 8 data. Figure 15-18. Data Stream Reception Flows Data Stream Reception Data Stream Initialization Data Stream Reception ISR FIFO Full? F1FI or F2FI = 1? Unmask FIFOs Full F1FM = 0 F2FM = 0 FIFO Full? F1FI or F2FI = 1? FIFO Reading read 8 data from MMDAT FIFO Reading read 8 data from MMDAT No More Data To Receive? No More Data To Receive? Send STOP Command Mask FIFOs Full F1FM = 1 F2FM = 1 a. Polling mode Send STOP Command b. Interrupt mode 121 4109J–8051–10/06 Figure 15-19. Data Block Reception Flows Data Block Reception Data Block Initialization Data Block Reception ISR Start Transmission DATEN = 1 DATEN = 0 Unmask FIFOs Full F1FM = 0 F2FM = 0 FIFO Full? F1EI or F2EI = 1? FIFO Full? F1EI or F2EI = 1? Start Transmission DATEN = 1 DATEN = 0 FIFO Reading read 8 data from MMDAT No More Data To Receive? FIFO Reading read 8 data from MMDAT No More Data To Receive? a. Polling mode 15.6.5 Mask FIFOs Full F1FM = 1 F2FM = 1 b. Interrupt mode Flow Control To allow transfer at high speed without taking care of CPU oscillator frequency, the FLOWC bit in MMCON2 allows control of the data flow in both transmission and reception. During transmission, setting the FLOWC bit has the following effects: • MMCLK is stopped when both FIFOs become empty: F1EI and F2EI set. • MMCLK is restarted when one of the FIFOs becomes full: F1EI or F2EI cleared. During reception, setting the FLOWC bit has the following effects: • MMCLK is stopped when both FIFOs become full: F1FI and F2FI set. • MMCLK is restarted when one of the FIFOs becomes empty: F1FI or F2FI cleared. As soon as the clock is stopped, the MMC bus is frozen and remains in its state until the clock is restored by writing or reading data in MMDAT. 15.7 15.7.1 Interrupt Description As shown in Figure 15-20, the MMC controller implements eight interrupt sources reported in MCBI, EORI, EOCI, EOFI, F2FI, F1FI, and F2EI flags in MMCINT register. These flags are detailed in the previous sections. All these sources are maskable separately using MCBM, EORM, EOCM, EOFM, F2FM, F1FM, and F2EM mask bits respectively in MMMSK register. 122 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C The interrupt request is generated each time an unmasked flag is set, and the global MMC controller interrupt enable bit is set (EMMC in IEN1 register). Reading the MMINT register automatically clears the interrupt flags (acknowledgment). This implies that register content must be saved and tested interrupt flag by interrupt flag to be sure not to forget any interrupts. Figure 15-20. MMC Controller Interrupt System MCBI MMINT.7 MCBM MMMSK.7 EORI MMINT.6 EORM EOCI MMMSK.6 MMINT.5 EOCM MMMSK.5 EOFI MMINT.4 MMC Interface Interrupt Request EOFM F2FI MMMSK.4 EMMC MMINT.3 IEN1.0 F2FM MMMSK.3 F1FI MMINT.2 F1FM F2EI MMMSK.2 MMINT.1 F2EM MMMSK.1 F1EI MMINT.0 F1EM MMMSK.0 15.8 Registers Table 102. MMCON0 Register MMCON0 (S:E4h) – MMC Control Register 0 7 6 5 4 3 2 1 0 DRPTR DTPTR CRPTR CTPTR MBLOCK DFMT RFMT CRCDIS Bit Number 7 Bit Mnemonic Description DRPTR Data Receive Pointer Reset Bit Set to reset the read pointer of the data FIFO. Clear to release the read pointer of the data FIFO. 123 4109J–8051–10/06 Bit Number Bit Mnemonic Description 6 DTPTR Data Transmit Pointer Reset Bit Set to reset the write pointer of the data FIFO. Clear to release the write pointer of the data FIFO. 5 CRPTR Command Receive Pointer Reset Bit Set to reset the read pointer of the receive command FIFO. Clear to release the read pointer of the receive command FIFO. 4 CTPTR Command Transmit Pointer Reset Bit Set to reset the write pointer of the transmit command FIFO. Clear to release the read pointer of the transmit command FIFO. 3 MBLOCK 2 DFMT Data Format Bit Set to select the block-oriented data format. Clear to select the stream data format. 1 RFMT Response Format Bit Set to select the 48-bit response format. Clear to select the 136-bit response format. 0 CRCDIS Multi-block Enable Bit Set to select multi-block data format. Clear to select single block data format. CRC7 Disable Bit Set to disable the CRC7 computation when receiving a response. Clear to enable the CRC7 computation when receiving a response. Reset Value = 0000 0000b 15.8.0.1 Table 103. MMCON1 Register MMCON1 (S:E5h) – MMC Control Register 1 7 6 5 4 3 2 1 0 BLEN3 BLEN2 BLEN1 BLEN0 DATDIR DATEN RESPEN CMDEN Bit Number Bit Mnemonic Description 7-4 BLEN3:0 Block Length Bits Refer to Table 101 for bits description. Do not program value > 1011b 3 DATDIR Data Direction Bit Set to select data transfer from host to card (write mode). Clear to select data transfer from card to host (read mode). 2 DATEN Data Transmission Enable Bit Set and clear to enable data transmission immediately or after response has been received. 1 RESPEN Response Enable Bit Set and clear to enable the reception of a response following a command transmission. 0 CMDEN Command Transmission Enable Bit Set and clear to enable transmission of the command FIFO to the card. Reset Value = 0000 0000b 124 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 15.8.0.2 Table 104. MMCON2 Register MMCON2 (S:E6h) – MMC Control Register 2 7 6 5 4 3 2 1 0 MMCEN DCR CCR - - DATD1 DATD0 FLOWC Bit Number Bit Mnemonic Description MMC Clock Enable Bit Set to enable the MCLK clocks and activate the MMC controller. Clear to disable the MMC clocks and freeze the MMC controller. 7 MMCEN 6 DCR Data Controller Reset Bit Set and clear to reset the data line controller in case of transfer abort. 5 CCR Command Controller Reset Bit Set and clear to reset the command line controller in case of transfer abort. 4-3 - Reserved The value read from these bits is always 0. Do not set these bits. 2-1 DATD1:0 Data Transmission Delay Bits Used to delay the data transmission after a response from 3 MMC clock periods (all bits cleared) to 9 MMC clock periods (all bits set) by step of 2 MMC clock periods. 0 FLOWC MMC Flow Control Bit Set to enable the flow control during data transfers. Clear to disable the flow control during data transfers. Reset Value = 0000 0000b 15.8.0.3 Table 105. MMSTA Register MMSTA (S:DEh Read Only) – MMC Control and Status Register 7 6 5 4 3 2 1 0 - - CBUSY CRC16S DATFS CRC7S RESPFS CFLCK Bit Number Bit Mnemonic Description 7-6 - 5 CBUSY Reserved The value read from these bits is always 0. Do not set these bits. Card Busy Flag Set by hardware when the card sends a busy state on the data line. Cleared by hardware when the card no more sends a busy state on the data line. 125 4109J–8051–10/06 Bit Number 4 3 2 Bit Mnemonic Description CRC16S DATFS CRC7S CRC16 Status Bit Transmission mode Set by hardware when the token response reports a good CRC. Cleared by hardware when the token response reports a bad CRC. Reception mode Set by hardware when the CRC16 received in the data block is correct. Cleared by hardware when the CRC16 received in the data block is not correct. Data Format Status Bit Transmission mode Set by hardware when the format of the token response is correct. Cleared by hardware when the format of the token response is not correct. Reception mode Set by hardware when the format of the frame is correct. Cleared by hardware when the format of the frame is not correct. CRC7 Status Bit Set by hardware when the CRC7 computed in the response is correct. Cleared by hardware when the CRC7 computed in the response is not correct. This bit is not relevant when CRCDIS is set. 1 0 RESPFS CFLCK Response Format Status Bit Set by hardware when the format of a response is correct. Cleared by hardware when the format of a response is not correct. Command FIFO Lock Bit Set by hardware to signal user not to write in the transmit command FIFO: busy state. Cleared by hardware to signal user the transmit command FIFO is available: idle state. Reset Value = 0000 0000b 15.8.0.4 Table 106. MMINT Register MMINT (S:E7h Read Only) – MMC Interrupt Register 7 6 5 4 3 2 1 0 MCBI EORI EOCI EOFI F2FI F1FI F2EI F1EI Bit Number 7 126 Bit Mnemonic Description MCBI MMC Card Busy Interrupt Flag Set by hardware when the card enters or exits its busy state (when the busy signal is asserted or deasserted on the data line). Cleared when reading MMINT. AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Bit Number Bit Mnemonic Description 6 EORI End of Response Interrupt Flag Set by hardware at the end of response reception. Cleared when reading MMINT. 5 EOCI End of Command Interrupt Flag Set by hardware at the end of command transmission. Clear when reading MMINT. 4 EOFI End of Frame Interrupt Flag Set by hardware at the end of frame (stream or block) transfer. Clear when reading MMINT. 3 F2FI FIFO 2 Full Interrupt Flag Set by hardware when second FIFO becomes full. Cleared by hardware when second FIFO becomes empty. 2 F1FI FIFO 1 Full Interrupt Flag Set by hardware when first FIFO becomes full. Cleared by hardware when first FIFO becomes empty. 1 F2EI FIFO 2 Empty Interrupt Flag Set by hardware when second FIFO becomes empty. Cleared by hardware when second FIFO becomes full. 0 F1EI FIFO 1 Empty Interrupt Flag Set by hardware when first FIFO becomes empty. Cleared by hardware when first FIFO becomes full. Reset Value = 0000 0011b 15.8.0.5 Table 107. MMMSK Register MMMSK (S:DFh) – MMC Interrupt Mask Register 7 6 5 4 3 2 1 0 MCBM EORM EOCM EOFM F2FM F1FM F2EM F1EM Bit Number Bit Mnemonic Description 7 MCBM MMC Card Busy Interrupt Mask Bit Set to prevent MCBI flag from generating an MMC interrupt. Clear to allow MCBI flag to generate an MMC interrupt. 6 EORM End Of Response Interrupt Mask Bit Set to prevent EORI flag from generating an MMC interrupt. Clear to allow EORI flag to generate an MMC interrupt. 5 EOCM End Of Command Interrupt Mask Bit Set to prevent EOCI flag from generating an MMC interrupt. Clear to allow EOCI flag to generate an MMC interrupt. 4 EOFM End Of Frame Interrupt Mask Bit Set to prevent EOFI flag from generating an MMC interrupt. Clear to allow EOFI flag to generate an MMC interrupt. 3 F2FM FIFO 2 Full Interrupt Mask Bit Set to prevent F2FI flag from generating an MMC interrupt. Clear to allow F2FI flag to generate an MMC interrupt. 127 4109J–8051–10/06 Bit Number Bit Mnemonic Description 2 F1FM FIFO 1 Full Interrupt Mask Bit Set to prevent F1FI flag from generating an MMC interrupt. Clear to allow F1FI flag to generate an MMC interrupt. 1 F2EM FIFO 2 Empty Interrupt Mask Bit Set to prevent F2EI flag from generating an MMC interrupt. Clear to allow F2EI flag to generate an MMC interrupt. 0 F1EM FIFO 1 Empty Interrupt Mask Bit Set to prevent F1EI flag from generating an MMC interrupt. Clear to allow F1EI flag to generate an MMC interrupt. Reset Value = 1111 1111b 15.8.0.6 Table 108. MMCMD Register MMCMD (S:DDh) – MMC Command Register 7 6 5 4 3 2 1 0 MC7 MC6 MC5 MC4 MC3 MC2 MC1 MC0 Bit Number 7-0 Bit Mnemonic Description MC7:0 MMC Command Receive Byte Output (read) register of the response FIFO. MMC Command Transmit Byte Input (write) register of the command FIFO. Reset Value = 1111 1111b 15.8.0.7 Table 109. MMDAT Register MMDAT (S:DCh) – MMC Data Register 7 6 5 4 3 2 1 0 MD7 MD6 MD5 MD4 MD3 MD2 MD1 MD0 Bit Number 7-0 Bit Mnemonic Description MD7:0 MMC Data Byte Input (write) or output (read) register of the data FIFO. Reset Value = 1111 1111b 15.8.0.8 Table 110. MMCLK Register MMCLK (S:EDh) – MMC Clock Divider Register 128 7 6 5 4 3 2 1 0 MMCD7 MMCD6 MMCD5 MMCD4 MMCD3 MMCD2 MMCD1 MMCD0 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Bit Number 7-0 Bit Mnemonic Description MMCD7:0 MMC Clock Divider 8-bit divider for MMC clock generation. Reset Value = 0000 0000b 129 4109J–8051–10/06 16. IDE/ATAPI Interface The AT8xC51SND1C provides an IDE/ATAPI interface allowing connection of devices such as CD-ROM reader, CompactFlash cards, Hard Disk Drive, etc. It consists of a 16-bit data transfer (read or write) between the AT8xC51SND1C and the IDE device. 16.1 Description The IDE interface mode is enabled by setting the EXT16 bit in AUXR (see Figure 19, page 30). As soon as this bit is set, all MOVX instructions read or write are done in a 16-bit mode compare to the standard 8-bit mode. P0 carries the low order multiplexed address and data bus (A7:0, D7:0) while P2 carries the high order multiplexed address and data bus (A15:8, D15:8). When writing data in IDE mode, the ACC contains D7:0 data (as in 8-bit mode) while DAT16H register (see Table 112) contains D15:8 data. When reading data in IDE mode, D7:0 data is returned in ACC while D15:8 data is returned in DAT16H. Figure 16-1 shows the IDE read bus cycle while Figure 16-2 shows the IDE write bus cycle. For simplicity, these figures depict the bus cycle waveforms in idealized form and do not provide precise timing information. For IDE bus cycle timing parameters refer to the Section “AC Characteristics”. IDE cycle takes 6 CPU clock periods which is equivalent to 12 oscillator clock periods in standard mode or 6 oscillator clock periods in X2 mode. For further information on X2 mode, refer to the Section “X2 Feature”, page 12. Slow IDE devices can be accessed by stretching the read and write cycles. This is done using the M0 bit in AUXR. Setting this bit changes the width of the RD and WR signals from 3 to 15 CPU clock periods. Figure 16-1. IDE Read Waveforms CPU Clock ALE RD(1) P0 P2 Notes: 130 P2 DPL or Ri D7:0 DPH or P2(2),(3) D15:8 P2 1. RD signal may be stretched using M0 bit in AUXR register. 2. When executing MOVX @Ri instruction, P2 outputs SFR content. 3. When executing MOVX @DPTR instruction, if DPHDIS is set (Page Access Mode), P2 outputs SFR content instead of DPH. AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 16-2. IDE Write Waveforms CPU Clock ALE WR(1) P0 P2 Notes: 16.1.1 P2 DPL or Ri D7:0 DPH or P2(2),(3) D15:8 P2 1. WR signal may be stretched using M0 bit in AUXR register. 2. When executing MOVX @Ri instruction, P2 outputs SFR content. 3. When executing MOVX @DPTR instruction, if DPHDIS is set (Page Access Mode), P2 outputs SFR content instead of DPH. IDE Device Connection Figure 16-3 and Figure 16-4 show 2 examples on how to interface up to 2 IDE devices to the AT8xC51SND1C. In both examples P0 carries IDE low order data bits D7:0, P2 carries IDE high order data bits D15:8, while RD and WR signals are respectively connected to the IDE nIOR and nIOW signals. Other IDE control signals are generated by the external address latch outputs in the first example while they are generated by some port I/Os in the second one. Using an external latch will achieve higher transfer rate. Figure 16-3. IDE Device Connection Example 1 AT8xC51SND1C IDE Device 0 P2 IDE Device 1 D15-8 D15-8 D7:0 D7:0 A2:0 A2:0 ALE nCS1:0 nCS1:0 Px.y nRESET nRESET RD WR nIOR nIOW nIOR nIOW P0 Latch Figure 16-4. IDE Device Connection Example 2 AT8xC51SND1C IDE Device 0 IDE Device 1 P2/A15:8 D15-8 D15-8 P0/AD7:0 D7:0 D7:0 A2:0 nCS1:0 nRESET nIOR nIOW A2:0 nCS1:0 nRESET nIOR nIOW P4.2:0 P4.4:3 P4.5 RD WR 131 4109J–8051–10/06 Table 111. External Data Memory Interface Signals 16.2 Signal Name Type Alternate Function A15:8 I/O Address Lines Upper address lines for the external bus. Multiplexed higher address and data lines for the IDE interface. P2.7:0 AD7:0 I/O Address/Data Lines Multiplexed lower address and data lines for the IDE interface. P0.7:0 ALE O Address Latch Enable ALE signals indicates that valid address information is available on lines AD7:0. RD O Read Read signal output to external data memory. P3.7 WR O Write Write signal output to external memory. P3.6 Description - Registers Table 112. DAT16H Register DAT16H (S:F9h) – Data 16 High Order Byte 7 6 5 4 3 2 1 0 D15 D14 D13 D12 D11 D10 D9 D8 Bit Number 7-0 Bit Mnemonic Description D15:8 Data 16 High Order Byte When EXT16 bit is set, DAT16H is set by software with the high order data Byte prior any MOVX write instruction. When EXT16 bit is set, DAT16H contains the high order data Byte after any MOVX read instruction. Reset Value =XXXX XXXXb 132 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 17. Serial I/O Port The serial I/O port in the AT8xC51SND1C provides both synchronous and asynchronous communication modes. It operates as a Synchronous Receiver and Transmitter in one single mode (Mode 0) and operates as an Universal Asynchronous Receiver and Transmitter (UART) in three full-duplex modes (Modes 1, 2 and 3). Asynchronous modes support framing error detection and multiprocessor communication with automatic address recognition. 17.1 Mode Selection SM0 and SM1 bits in SCON register (see Figure 115) are used to select a mode among the single synchronous and the three asynchronous modes according to Table 113. Table 113. Serial I/O Port Mode Selection 17.2 SM0 SM1 Mode Description Baud Rate 0 0 0 Synchronous Shift Register Fixed/Variable 0 1 1 8-bit UART Variable 1 0 2 9-bit UART Fixed 1 1 3 9-bit UART Variable Baud Rate Generator Depending on the mode and the source selection, the baud rate can be generated from either the Timer 1 or the Internal Baud Rate Generator. The Timer 1 can be used in Modes 1 and 3 while the Internal Baud Rate Generator can be used in Modes 0, 1 and 3. The addition of the Internal Baud Rate Generator allows freeing of the Timer 1 for other purposes in the application. It is highly recommended to use the Internal Baud Rate Generator as it allows higher and more accurate baud rates than Timer 1. Baud rate formulas depend on the modes selected and are given in the following mode sections. 17.2.1 Timer 1 When using Timer 1, the Baud Rate is derived from the overflow of the timer. As shown in Figure 17-1 Timer 1 is used in its 8-bit auto-reload mode (detailed in Section "Mode 2 (8-bit Timer with Auto-Reload)", page 54). SMOD1 bit in PCON register allows doubling of the generated baud rate. 133 4109J–8051–10/06 Figure 17-1. Timer 1 Baud Rate Generator Block Diagram PER CLOCK ÷6 0 TL1 (8 bits) 1 Overflow ÷2 T1 0 To serial Port 1 C/T1# TMOD.6 SMOD1 INT1 PCON.7 TH1 (8 bits) GATE1 T1 CLOCK TMOD.7 TR1 TCON.6 17.2.2 Internal Baud Rate Generator When using the Internal Baud Rate Generator, the Baud Rate is derived from the overflow of the timer. As shown in Figure 17-2 the Internal Baud Rate Generator is an 8-bit auto-reload timer fed by the peripheral clock or by the peripheral clock divided by 6 depending on the SPD bit in BDRCON register (see Table 119). The Internal Baud Rate Generator is enabled by setting BBR bit in BDRCON register. SMOD1 bit in PCON register allows doubling of the generated baud rate. Figure 17-2. Internal Baud Rate Generator Block Diagram PER CLOCK ÷6 0 BRG (8 bits) 1 Overflow ÷2 0 To serial Port 1 SPD BRR BDRCON.1 BDRCON.4 SMOD1 PCON.7 BRL (8 bits) 17.3 IBRG CLOCK Synchronous Mode (Mode 0) Mode 0 is a half-duplex, synchronous mode, which is commonly used to expand the I/0 capabilities of a device with shift registers. The transmit data (TXD) pin outputs a set of eight clock pulses while the receive data (RXD) pin transmits or receives a Byte of data. The 8-bit data are transmitted and received least-significant bit (LSB) first. Shifts occur at a fixed Baud Rate (see Section "Baud Rate Selection (Mode 0)", page 136). Figure 17-3 shows the serial port block diagram in Mode 0. 134 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 17-3. Serial I/O Port Block Diagram (Mode 0) SCON.6 SCON.7 SM1 SM0 SBUF Tx SR Mode Decoder RXD M3 M2 M1 M0 SBUF Rx SR Mode Controller PER CLOCK 17.3.1 TI RI SCON.1 SCON.0 Baud Rate Controller BRG CLOCK TXD Transmission (Mode 0) To start a transmission mode 0, write to SCON register clearing bits SM0, SM1. As shown in Figure 17-4, writing the Byte to transmit to SBUF register starts the transmission. Hardware shifts the LSB (D0) onto the RXD pin during the first clock cycle composed of a high level then low level signal on TXD. During the eighth clock cycle the MSB (D7) is on the RXD pin. Then, hardware drives the RXD pin high and asserts TI to indicate the end of the transmission. Figure 17-4. Transmission Waveforms (Mode 0) TXD Write to SBUF RXD D0 D1 D2 D3 D4 D5 D6 D7 TI 17.3.2 Reception (Mode 0) To start a reception in mode 0, write to SCON register clearing SM0, SM1 and RI bits and setting the REN bit. As shown in Figure 17-5, Clock is pulsed and the LSB (D0) is sampled on the RXD pin. The D0 bit is then shifted into the shift register. After eight samplings, the MSB (D7) is shifted into the shift register, and hardware asserts RI bit to indicate a completed reception. Software can then read the received Byte from SBUF register. Figure 17-5. Reception Waveforms (Mode 0) TXD Write to SCON RXD Set REN, Clear RI D0 D1 D2 D3 D4 D5 D6 D7 RI 135 4109J–8051–10/06 17.3.3 Baud Rate Selection (Mode 0) In mode 0, the baud rate can be either, fixed or variable. As shown in Figure 17-6, the selection is done using M0SRC bit in BDRCON register. Figure 17-7 gives the baud rate calculation formulas for each baud rate source. Figure 17-6. Baud Rate Source Selection (mode 0) PER CLOCK ÷6 0 To Serial Port 1 IBRG CLOCK M0SRC BDRCON.0 Figure 17-7. Baud Rate Formulas (Mode 0) Baud_Rate= Baud_Rate= FPER 6 BRL= 256 - a. Fixed Formula 17.4 6 6 2SMOD1 ⋅ FPER ⋅ 32 ⋅ (256 -BRL) (1-SPD) 2SMOD1 ⋅ FPER ⋅ 32 ⋅ Baud_Rate (1-SPD) b. Variable Formula Asynchronous Modes (Modes 1, 2 and 3) The Serial Port has one 8-bit and 2 9-bit asynchronous modes of operation. Figure 17-8 shows the Serial Port block diagram in such asynchronous modes. Figure 17-8. Serial I/O Port Block Diagram (Modes 1, 2 and 3) SCON.6 SCON.7 SCON.3 SM1 SM0 TB8 Mode Decoder SBUF Tx SR TXD Rx SR RXD M3 M2 M1 M0 T1 CLOCK Mode & Clock Controller IBRG CLOCK PER CLOCK 17.4.0.1 SBUF Rx RB8 SCON.2 SM2 TI RI SCON.4 SCON.1 SCON.0 Mode 1 Mode 1 is a full-duplex, asynchronous mode. The data frame (see Figure 17-9) consists of 10 bits: one start, eight data bits and one stop bit. Serial data is transmitted on the TXD pin and received on the RXD pin. When a data is received, the stop bit is read in the RB8 bit in SCON register. 136 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 17-9. Data Frame Format (Mode 1) Mode 1 D0 D1 D2 Start bit 17.4.0.2 D3 D4 D5 D6 D7 8-bit data Stop bit Modes 2 and 3 Modes 2 and 3 are full-duplex, asynchronous modes. The data frame (see Figure 17-10) consists of 11 bits: one start bit, eight data bits (transmitted and received LSB first), one programmable ninth data bit and one stop bit. Serial data is transmitted on the TXD pin and received on the RXD pin. On receive, the ninth bit is read from RB8 bit in SCON register. On transmit, the ninth data bit is written to TB8 bit in SCON register. Alternatively, you can use the ninth bit can be used as a command/data flag. Figure 17-10. Data Frame Format (Modes 2 and 3) D0 D1 D2 D3 Start bit 17.4.1 D4 D5 D6 D7 9-bit data D8 Stop bit Transmission (Modes 1, 2 and 3) To initiate a transmission, write to SCON register, set the SM0 and SM1 bits according to Table 113, and set the ninth bit by writing to TB8 bit. Then, writing the Byte to be transmitted to SBUF register starts the transmission. 17.4.2 Reception (Modes 1, 2 and 3) To prepare for reception, write to SCON register, set the SM0 and SM1 bits according to Table 113, and set the REN bit. The actual reception is then initiated by a detected high-to-low transition on the RXD pin. 17.4.3 Framing Error Detection (Modes 1, 2 and 3) Framing error detection is provided for the three asynchronous modes. To enable the framing bit error detection feature, set SMOD0 bit in PCON register as shown in Figure 17-11. When this feature is enabled, the receiver checks each incoming data frame for a valid stop bit. An invalid stop bit may result from noise on the serial lines or from simultaneous transmission by 2 devices. If a valid stop bit is not found, the software sets FE bit in SCON register. Software may examine FE bit after each reception to check for data errors. Once set, only software or a chip reset clear FE bit. Subsequently received frames with valid stop bits cannot clear FE bit. When the framing error detection feature is enabled, RI rises on stop bit instead of the last data bit as detailed in Figure 17-17. Figure 17-11. Framing Error Block Diagram Framing Error Controller FE 1 SM0/FE 0 SCON.7 SM0 SMOD0 PCON.6 137 4109J–8051–10/06 17.4.4 Baud Rate Selection (Modes 1 and 3) In modes 1 and 3, the Baud Rate is derived either from the Timer 1 or the Internal Baud Rate Generator and allows different baud rate in reception and transmission. As shown in Figure 17-12 the selection is done using RBCK and TBCK bits in BDRCON register. Figure 17-13 gives the baud rate calculation formulas for each baud rate source while Table 114 details Internal Baud Rate Generator configuration for different peripheral clock frequencies and giving baud rates closer to the standard baud rates. Figure 17-12. Baud Rate Source Selection (Modes 1 and 3) T1 CLOCK 0 ÷ 16 1 IBRG CLOCK T1 CLOCK To Serial Rx Port 0 To Serial Tx Port ÷ 16 1 IBRG CLOCK RBCK TBCK BDRCON.2 BDRCON.3 Figure 17-13. Baud Rate Formulas (Modes 1 and 3) Baud_Rate= 6 BRL= 256 - 6 2SMOD1 ⋅ FPER ⋅ 32 ⋅ (256 -BRL) Baud_Rate= (1-SPD) 2SMOD1 ⋅ FPER ⋅ 32 ⋅ Baud_Rate 2SMOD1 ⋅ FPER 6 ⋅ 32 ⋅ (256 -TH1) 2SMOD1 ⋅ FPER 192 ⋅ Baud_Rate TH1= 256 - (1-SPD) a. IBRG Formula b. T1 Formula Table 114. Internal Baud Rate Generator Value FPER = 6 MHz(1) FPER = 8 MHz(1) FPER = 10 MHz(1) Baud Rate SPD SMOD1 BRL Error % SPD SMOD1 BRL Error % SPD SMOD1 BRL Error % 115200 - - - - - - - - - - - - 57600 - - - - 1 1 247 3.55 1 1 245 1.36 38400 1 1 246 2.34 1 1 243 0.16 1 1 240 1.73 19200 1 1 236 2.34 1 1 230 0.16 1 1 223 1.36 9600 1 1 217 0.16 1 1 204 0.16 1 1 191 0.16 4800 1 1 178 0.16 1 1 152 0.16 1 1 126 0.16 FPER = 12 MHz(2) FPER = 16 MHz(2) FPER = 20 MHz(2) Baud Rate SPD SMOD1 BRL Error % SPD SMOD1 BRL Error % SPD SMOD1 BRL Error % 115200 - - - - 1 1 247 3.55 1 1 245 1.36 57600 1 1 243 0.16 1 1 239 2.12 1 1 234 1.36 38400 1 1 236 2.34 1 1 230 0.16 1 1 223 1.36 19200 1 1 217 0.16 1 1 204 0.16 1 1 191 0.16 138 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C FPER = 12 MHz(2) FPER = 16 MHz(2) FPER = 20 MHz(2) Baud Rate SPD SMOD1 BRL Error % SPD SMOD1 BRL Error % SPD SMOD1 BRL Error % 9600 1 1 178 0.16 1 1 152 0.16 1 1 126 0.16 4800 1 1 100 0.16 1 1 48 0.16 1 0 126 0.16 Notes: 17.4.5 1. These frequencies are achieved in X1 mode, FPER = FOSC ÷ 2. 2. These frequencies are achieved in X2 mode, FPER = FOSC. Baud Rate Selection (Mode 2) In mode 2, the baud rate can only be programmed to 2 fixed values: 1/16 or 1/32 of the peripheral clock frequency. As shown in Figure 17-14 the selection is done using SMOD1 bit in PCON register. Figure 17-15 gives the baud rate calculation formula depending on the selection. Figure 17-14. Baud Rate Generator Selection (Mode 2) PER CLOCK ÷2 0 ÷ 16 To Serial Port 1 SMOD1 PCON.7 Figure 17-15. Baud Rate Formula (Mode 2) Baud_Rate= 17.5 2SMOD1 ⋅ FPER 32 Multiprocessor Communication (Modes 2 and 3) Modes 2 and 3 provide a ninth-bit mode to facilitate multiprocessor communication. To enable this feature, set SM2 bit in SCON register. When the multiprocessor communication feature is enabled, the serial Port can differentiate between data frames (ninth bit clear) and address frames (ninth bit set). This allows the AT8xC51SND1C to function as a slave processor in an environment where multiple slave processors share a single serial line. When the multiprocessor communication feature is enabled, the receiver ignores frames with the ninth bit clear. The receiver examines frames with the ninth bit set for an address match. If the received address matches the slaves address, the receiver hardware sets RB8 and RI bits in SCON register, generating an interrupt. The addressed slave’s software then clears SM2 bit in SCON register and prepares to receive the data Bytes. The other slaves are unaffected by these data Bytes because they are waiting to respond to their own addresses. 139 4109J–8051–10/06 17.6 Automatic Address Recognition The automatic address recognition feature is enabled when the multiprocessor communication feature is enabled (SM2 bit in SCON register is set). Implemented in hardware, automatic address recognition enhances the multiprocessor communication feature by allowing the Serial Port to examine the address of each incoming command frame. Only when the Serial Port recognizes its own address, the receiver sets RI bit in SCON register to generate an interrupt. This ensures that the CPU is not interrupted by command frames addressed to other devices. If desired, the automatic address recognition feature in mode 1 may be enabled. In this configuration, the stop bit takes the place of the ninth data bit. Bit RI is set only when the received command frame address matches the device’s address and is terminated by a valid stop bit. To support automatic address recognition, a device is identified by a given address and a broadcast address. Note: 17.6.1 The multiprocessor communication and automatic address recognition features cannot be enabled in mode 0 (i.e, setting SM2 bit in SCON register in mode 0 has no effect). Given Address Each device has an individual address that is specified in SADDR register; the SADEN register is a mask Byte that contains don’t care bits (defined by zeros) to form the device’s given address. The don’t care bits provide the flexibility to address one or more slaves at a time. The following example illustrates how a given address is formed. To address a device by its individual address, the SADEN mask Byte must be 1111 1111b. For example: SADDR = 0101 0110b SADEN = 1111 1100b Given = 0101 01XXb The following is an example of how to use given addresses to address different slaves: Slave A:SADDR = 1111 0001b SADEN = 1111 1010b Given = 1111 0X0Xb Slave B:SADDR = 1111 0011b SADEN = 1111 1001b Given = 1111 0XX1b Slave C:SADDR = 1111 0011b SADEN = 1111 1101b Given = 1111 00X1b The SADEN Byte is selected so that each slave may be addressed separately. For slave A, bit 0 (the LSB) is a don’t-care bit; for slaves B and C, bit 0 is a 1. To communicate with slave A only, the master must send an address where bit 0 is clear (e.g. 1111 0000B). For slave A, bit 1 is a 0; for slaves B and C, bit 1 is a don’t care bit. To communicate with slaves A and B, but not slave C, the master must send an address with bits 0 and 1 both set (e.g. 1111 0011B). To communicate with slaves A, B and C, the master must send an address with bit 0 set, bit 1 clear, and bit 2 clear (e.g. 1111 0001B). 140 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 17.6.2 Broadcast Address A broadcast address is formed from the logical OR of the SADDR and SADEN registers with zeros defined as don’t-care bits, e.g.: SADDR = 0101 0110b SADEN = 1111 1100b (SADDR | SADEN)=1111 111Xb The use of don’t-care bits provides flexibility in defining the broadcast address, however in most applications, a broadcast address is FFh. The following is an example of using broadcast addresses: Slave A:SADDR = 1111 0001b SADEN = 1111 1010b Given = 1111 1X11b, Slave B:SADDR = 1111 0011b SADEN = 1111 1001b Given = 1111 1X11b, Slave C:SADDR = 1111 0010b SADEN = 1111 1101b Given = 1111 1111b, For slaves A and B, bit 2 is a don’t care bit; for slave C, bit 2 is set. To communicate with all of the slaves, the master must send the address FFh. To communicate with slaves A and B, but not slave C, the master must send the address FBh. 17.6.3 Reset Address On reset, the SADDR and SADEN registers are initialized to 00h, i.e. the given and broadcast addresses are XXXX XXXXb (all don’t care bits). This ensures that the Serial Port is backwards compatible with the 80C51 microcontrollers that do not support automatic address recognition. 17.7 Interrupt The Serial I/O Port handles 2 interrupt sources that are the “end of reception” (RI in SCON) and “end of transmission” (TI in SCON) flags. As shown in Figure 17-16 these flags are combined together to appear as a single interrupt source for the C51 core. Flags must be cleared by software when executing the serial interrupt service routine. The serial interrupt is enabled by setting ES bit in IEN0 register. This assumes interrupts are globally enabled by setting EA bit in IEN0 register. Depending on the selected mode and weather the framing error detection is enabled or disabled, RI flag is set during the stop bit or during the ninth bit as detailed in Figure 17-17. 141 4109J–8051–10/06 Figure 17-16. Serial I/O Interrupt System SCON.0 RI Serial I/O Interrupt Request TI SCON.1 ES IEN0.4 Figure 17-17. Interrupt Waveforms a. Mode 1 RXD D0 D1 D2 D3 Start Bit D4 D5 D6 D7 8-bit Data Stop Bit RI SMOD0 = X FE SMOD0 = 1 b. Mode 2 and 3 RXD D0 D1 D2 D3 Start bit D4 D5 D6 D7 D8 9-bit data Stop bit RI SMOD0 = 0 RI SMOD0 = 1 FE SMOD0 = 1 17.8 Registers Table 115. SCON Register SCON (S:98h) – Serial Control Register 142 7 6 5 4 3 2 1 0 FE/SM0 OVR/SM1 SM2 REN TB8 RB8 TI RI AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Bit Number Bit Mnemonic Description FE 7 Framing Error Bit To select this function, set SMOD0 bit in PCON register. Set by hardware to indicate an invalid stop bit. Must be cleared by software. SM0 Serial Port Mode Bit 0 Refer to Table 113 for mode selection. SM1 Serial Port Mode Bit 1 Refer to Table 113 for mode selection. 5 SM2 Serial Port Mode Bit 2 Set to enable the multiprocessor communication and automatic address recognition features. Clear to disable the multiprocessor communication and automatic address recognition features. 4 REN Receiver Enable Bit Set to enable reception. Clear to disable reception. 3 TB8 Transmit Bit 8 Modes 0 and 1: Not used. Modes 2 and 3: Software writes the ninth data bit to be transmitted to TB8. 2 RB8 Receiver Bit 8 Mode 0: Not used. Mode 1 (SM2 cleared): Set or cleared by hardware to reflect the stop bit received. Modes 2 and 3 (SM2 set): Set or cleared by hardware to reflect the ninth bit received. 1 TI Transmit Interrupt Flag Set by the transmitter after the last data bit is transmitted. Must be cleared by software. 0 RI Receive Interrupt Flag Set by the receiver after the stop bit of a frame has been received. Must be cleared by software. 6 Reset Value = 0000 0000b Table 116. SBUF Register SBUF (S:99h) – Serial Buffer Register 7 6 5 4 3 2 1 0 SD7 SD6 SD5 SD4 SD3 SD2 SD1 SD0 Bit Number 7-0 Bit Mnemonic Description SD7:0 Serial Data Byte Read the last data received by the serial I/O Port. Write the data to be transmitted by the serial I/O Port. Reset value = XXXX XXXXb Table 117. SADDR Register 143 4109J–8051–10/06 SADDR (S:A9h) – Slave Individual Address Register 7 6 5 4 3 2 1 0 SAD7 SAD6 SAD5 SAD4 SAD3 SAD2 SAD1 SAD0 Bit Number 7-0 Bit Mnemonic Description SAD7:0 Slave Individual Address Reset Value = 0000 0000b Table 118. SADEN Register SADEN (S:B9h) – Slave Individual Address Mask Byte Register 7 6 5 4 3 2 1 0 SAE7 SAE6 SAE5 SAE4 SAE3 SAE2 SAE1 SAE0 Bit Number 7-0 Bit Mnemonic Description SAE7:0 Slave Address Mask Byte Reset Value = 0000 0000b Table 119. BDRCON Register BDRCON (S:92h) – Baud Rate Generator Control Register 7 6 5 4 3 2 1 0 - - - BRR TBCK RBCK SPD M0SRC Bit Number Bit Mnemonic Description Reserved The value read from these bits are indeterminate. Do not set these bits. 7-5 - 4 BRR Baud Rate Run Bit Set to enable the baud rate generator. Clear to disable the baud rate generator. 3 TBCK Transmission Baud Rate Selection Bit Set to select the baud rate generator as transmission baud rate generator. Clear to select the Timer 1 as transmission baud rate generator. 2 RBCK Reception Baud Rate Selection Bit Set to select the baud rate generator as reception baud rate generator. Clear to select the Timer 1 as reception baud rate generator. 1 SPD 0 M0SRC Baud Rate Speed Bit Set to select high speed baud rate generation. Clear to select low speed baud rate generation. Mode 0 Baud Rate Source Bit Set to select the variable baud rate generator in Mode 0. Clear to select fixed baud rate in Mode 0. Reset Value = XXX0 0000b 144 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Table 120. BRL Register BRL (S:91h) – Baud Rate Generator Reload Register 7 6 5 4 3 2 1 0 BRL7 BRL6 BRL5 BRL4 BRL3 BRL2 BRL1 BRL0 Bit Number 7-0 Bit Mnemonic Description BRL7:0 Baud Rate Reload Value Reset Value = 0000 0000b 145 4109J–8051–10/06 18. Synchronous Peripheral Interface The AT8xC51SND1C implements a Synchronous Peripheral Interface with master and slave modes capability. Figure 18-1 shows an SPI bus configuration using the AT8xC51SND1C as master connected to slave peripherals while Figure 18-2 shows an SPI bus configuration using the AT8xC51SND1C as slave of an other master. The bus is made of three wires connecting all the devices together: • Master Output Slave Input (MOSI): it is used to transfer data in series from the master to a slave. It is driven by the master. • Master Input Slave Output (MISO): it is used to transfer data in series from a slave to the master. It is driven by the selected slave. • Serial Clock (SCK): it is used to synchronize the data transmission both in and out the devices through their MOSI and MISO lines. It is driven by the master for eight clock cycles which allows to exchange one Byte on the serial lines. Each slave peripheral is selected by one Slave Select pin (SS). If there is only one slave, it may be continuously selected with SS tied to a low level. Otherwise, the AT8xC51SND1C may select each device by software through port pins (Pn.x). Special care should be taken not to select 2 slaves at the same time to avoid bus conflicts. Figure 18-1. Typical Master SPI Bus Configuration Pn.z Pn.y SS Pn.x AT8xC51SND1C P4.0 P4.1 P4.2 SO DataFlash 1 SI SCK SS DataFlash 2 SO SI SCK SS SO LCD Controller SI SCK MISO MOSI SCK Figure 18-2. Typical Slave SPI Bus Configuration SSn SS SS1 SS0 MASTER SS SO Slave 1 SI SCK SS SO Slave 2 AT8xC51SND1C Slave n SI MISO MOSI SCK SCK MISO MOSI SCK 146 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 18.1 Description The SPI controller interfaces with the C51 core through three special function registers: SPCON, the SPI control register (see Table 122); SPSTA, the SPI status register (see Table 123); and SPDAT, the SPI data register (see Table 124). 18.1.1 Master Mode The SPI operates in master mode when the MSTR bit in SPCON is set. Figure 18-3 shows the SPI block diagram in master mode. Only a master SPI module can initiate transmissions. Software begins the transmission by writing to SPDAT. Writing to SPDAT writes to the shift register while reading SPDAT reads an intermediate register updated at the end of each transfer. The Byte begins shifting out on the MOSI pin under the control of the bit rate generator. This generator also controls the shift register of the slave peripheral through the SCK output pin. As the Byte shifts out, another Byte shifts in from the slave peripheral on the MISO pin. The Byte is transmitted most significant bit (MSB) first. The end of transfer is signaled by SPIF being set. When the AT8xC51SND1C is the only master on the bus, it can be useful not to use SS pin and get it back to I/O functionality. This is achieved by setting SSDIS bit in SPCON. Figure 18-3. SPI Master Mode Block Diagram MOSI/P4.1 I 8-bit Shift Register SPDAT WR SCK/P4.2 SPDAT RD Q Internal Bus MISO/P4.0 SS/P4.3 MODF SSDIS SPCON.5 SPSTA.4 Control and Clock Logic WCOL SPSTA.6 PER CLOCK Bit Rate Generator SPIF SPSTA.7 SPEN SPCON.6 Note: 18.1.2 SPR2:0 CPHA CPOL SPCON SPCON.2 SPCON.3 MSTR bit in SPCON is set to select master mode. Slave Mode The SPI operates in slave mode when the MSTR bit in SPCON is cleared and data has been loaded in SPDAT. Figure 18-4 shows the SPI block diagram in slave mode. In slave mode, before a data transmission occurs, the SS pin of the slave SPI must be asserted to low level. SS must remain low until the transmission of the Byte is complete. In the slave SPI module, data enters the shift register through the MOSI pin under the control of the serial clock provided by the master SPI module on the SCK input pin. When the master starts a transmission, the data in the shift register begins shifting out on the MISO pin. The end of transfer is signaled by SPIF being set. 147 4109J–8051–10/06 When the AT8xC51SND1C is the only slave on the bus, it can be useful not to use SS pin and get it back to I/O functionality. This is achieved by setting SSDIS bit in SPCON. This bit has no effect when CPHA is cleared (see Section "SS Management", page 149). Figure 18-4. SPI Slave Mode Block Diagram MISO/P4.2 I 8-bit Shift Register SPDAT WR SPDAT RD SCK/P4.2 Q Internal Bus MOSI/P4.1 Control and Clock Logic SS/P4.3 SPIF SPSTA.7 SSDIS SPCON.5 Note: 18.1.3 CPHA CPOL SPCON.2 SPCON.3 1. MSTR bit in SPCON is cleared to select slave mode. Bit Rate The bit rate can be selected from seven predefined bit rates using the SPR2, SPR1 and SPR0 control bits in SPCON according to Table 121. These bit rates are derived from the peripheral clock (FPER) issued from the Clock Controller block as detailed in Section "Oscillator", page 12. Table 121. Serial Bit Rates Bit Rate (kHz) Vs FPER Notes: 18.1.4 6 MHz(1) 8 MHz(1) 10 MHz(1) 12 MHz(2) 16 MHz(2) 20 MHz(2) SPR2 SPR1 SPR0 FPER Divider 0 0 0 3000 4000 5000 6000 8000 10000 2 0 0 1 1500 2000 2500 3000 4000 5000 4 0 1 0 750 1000 1250 1500 2000 2500 8 0 1 1 375 500 625 750 1000 1250 16 1 0 0 187.5 250 312.5 375 500 625 32 1 0 1 93.75 125 156.25 187.5 250 312.5 64 1 1 0 46.875 62.5 78.125 93.75 125 156.25 128 1 1 1 6000 8000 10000 12000 16000 20000 1 1. These frequencies are achieved in X1 mode, FPER = FOSC ÷ 2. 2. These frequencies are achieved in X2 mode, FPER = FOSC. Data Transfer The Clock Polarity bit (CPOL in SPCON) defines the default SCK line level in idle state(1) while the Clock Phase bit (CPHA in SPCON) defines the edges on which the input data are sampled and the edges on which the output data are shifted (see Figure 18-5 and Figure 18-6). The SI signal is output from the selected slave and the SO signal is the output from the master. The AT8xC51SND1C captures data from the SI line while the selected slave captures data from the SO line. 148 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C For simplicity, Figure 18-5 and Figure 18-6 depict the SPI waveforms in idealized form and do not provide precise timing information. For timing parameters refer to the Section “AC Characteristics”. Note: 1. When the peripheral is disabled (SPEN = 0), default SCK line is high level. Figure 18-5. Data Transmission Format (CPHA = 0) SCK Cycle Number 1 2 3 4 5 6 7 8 MSB bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 LSB bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 LSB SPEN (Internal) SCK (CPOL = 0) SCK (CPOL = 1) MOSI (From Master) MISO (From Slave) MSB SS (to slave) Capture point Figure 18-6. Data Transmission Format (CPHA = 1) 1 2 3 4 5 6 7 8 MOSI (from master) MSB bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 LSB MISO (from slave) MSB bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 SCK cycle number SPEN (internal) SCK (CPOL = 0) SCK (CPOL = 1) LSB SS (to slave) Capture point 18.1.5 SS Management Figure 18-5 shows an SPI transmission with CPHA = 0, where the first SCK edge is the MSB capture point. Therefore the slave starts to output its MSB as soon as it is selected: SS asserted to low level. SS must then be deasserted between each Byte transmission (see Figure 18-7). SPDAT must be loaded with a data before SS is asserted again. Figure 18-6 shows an SPI transmission with CPHA = 1, where the first SCK edge is used by the slave as a start of transmission signal. Therefore, SS may remain asserted between each Byte transmission (see Figure 18-7). 149 4109J–8051–10/06 Figure 18-7. SS Timing Diagram SI/SO Byte 1 Byte 2 Byte 3 SS (CPHA = 0) SS (CPHA = 1) 18.1.6 Error Conditions The following flags signal the SPI error conditions: 18.2 • MODF in SPSTA signals a mode fault. MODF flag is relevant only in master mode when SS usage is enabled (SSDIS bit cleared). It signals when set that an other master on the bus has asserted SS pin and so, may create a conflict on the bus with 2 master sending data at the same time. • A mode fault automatically disables the SPI (SPEN cleared) and configures the SPI in slave mode (MSTR cleared). MODF flag can trigger an interrupt as explained in Section "Interrupt", page 150. MODF flag is cleared by reading SPSTA and re-configuring SPI by writing to SPCON. • WCOL in SPSTA signals a write collision. WCOL flag is set when SPDAT is loaded while a transfer is on-going. In this case data is not written to SPDAT and transfer continue uninterrupted. WCOL flag does not trigger any interrupt and is relevant jointly with SPIF flag. WCOL flag is cleared after reading SPSTA and writing new data to SPDAT while no transfer is on-going. Interrupt The SPI handles 2 interrupt sources that are the “end of transfer” and the “mode fault” flags. As shown in Figure 18-8, these flags are combined toghether to appear as a single interrupt source for the C51 core. The SPIF flag is set at the end of an 8-bit shift in and out and is cleared by reading SPSTA and then reading from or writing to SPDAT. The MODF flag is set in case of mode fault error and is cleared by reading SPSTA and then writing to SPCON. The SPI interrupt is enabled by setting ESPI bit in IEN1 register. This assumes interrupts are globally enabled by setting EA bit in IEN0 register. Figure 18-8. SPI Interrupt System SPIF SPI Controller Interrupt Request SPSTA.7 MODF SPSTA.4 ESPI IEN1.2 18.3 Configuration The SPI configuration is made through SPCON. 18.3.1 Master Configuration The SPI operates in master mode when the MSTR bit in SPCON is set. 150 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 18.3.2 Slave Configuration The SPI operates in slave mode when the MSTR bit in SPCON is cleared and data has been loaded is SPDAT. 18.3.3 Data Exchange There are 2 possible methods to exchange data in master and slave modes: 18.3.4 • polling • interrupts Master Mode with Polling Policy Figure 18-9 shows the initialization phase and the transfer phase flows using the polling method. Using this flow prevents any overrun error occurrence. The bit rate is selected according to Table 121. The transfer format depends on the slave peripheral. SS may be deasserted between transfers depending also on the slave peripheral. SPIF flag is cleared when reading SPDAT (SPSTA has been read before by the “end of transfer” check). This polling method provides the fastest effective transmission and is well adapted when communicating at high speed with other microcontrollers. However, the procedure may then be interrupted at any time by higher priority tasks. 151 4109J–8051–10/06 Figure 18-9. Master SPI Polling Flows SPI Initialization Polling Policy SPI Transfer Polling Policy Disable interrupt SPIE = 0 Select Slave Pn.x = L Select Master Mode MSTR = 1 Start Transfer write data in SPDAT Select Bit Rate program SPR2:0 End Of Transfer? SPIF = 1? Select Format program CPOL & CPHA Get Data Received read SPDAT Enable SPI SPEN = 1 Last Transfer? Deselect Slave Pn.x = H 18.3.5 Master Mode with Interrupt Figure 18-10 shows the initialization phase and the transfer phase flows using the interrupt. Using this flow prevents any overrun error occurrence. The bit rate is selected according to Table 121. The transfer format depends on the slave peripheral. SS may be deasserted between transfers depending also on the slave peripheral. Reading SPSTA at the beginning of the ISR is mandatory for clearing the SPIF flag. Clear is effective when reading SPDAT. 152 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 18-10. Master SPI Interrupt Flows SPI Initialization Interrupt Policy SPI Interrupt Service Routine Select Master Mode MSTR = 1 Read Status Read SPSTA Select Bit Rate program SPR2:0 Get Data Received read SPDAT Select Format program CPOL & CPHA Start New Transfer write data in SPDAT Enable interrupt ESPI =1 Last Transfer? Enable SPI SPEN = 1 Deselect Slave Pn.x = H Select Slave Pn.x = L Disable interrupt SPIE = 0 Start Transfer write data in SPDAT 18.3.6 Slave Mode with Polling Policy Figure 18-11 shows the initialization phase and the transfer phase flows using the polling. The transfer format depends on the master controller. SPIF flag is cleared when reading SPDAT (SPSTA has been read before by the “end of reception” check). This provides the fastest effective transmission and is well adapted when communicating at high speed with other Microcontrollers. However, the process may then be interrupted at any time by higher priority tasks. 153 4109J–8051–10/06 Figure 18-11. Slave SPI Polling Flows SPI Initialization Polling Policy Disable interrupt SPIE = 0 SPI Transfer Polling Policy Data Received? SPIF = 1? Select Slave Mode MSTR = 0 Get Data Received read SPDAT Select Format program CPOL & CPHA Prepare Next Transfer write data in SPDAT Enable SPI SPEN = 1 Prepare Transfer write data in SPDAT 18.3.7 Slave Mode with Interrupt Policy Figure 18-10 shows the initialization phase and the transfer phase flows using the interrupt. The transfer format depends on the master controller. Reading SPSTA at the beginning of the ISR is mandatory for clearing the SPIF flag. Clear is effective when reading SPDAT. 154 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 18-12. Slave SPI Interrupt Policy Flows SPI Initialization Interrupt Policy SPI Interrupt Service Routine Select Slave Mode MSTR = 0 Get Status Read SPSTA Select Format program CPOL & CPHA Get Data Received read SPDAT Enable interrupt ESPI =1 Prepare New Transfer write data in SPDAT Enable SPI SPEN = 1 Prepare Transfer write data in SPDAT 18.4 Registers Table 122. SPCON Register SPCON (S:C3h) – SPI Control Register 7 6 5 4 3 2 1 0 SPR2 SPEN SSDIS MSTR CPOL CPHA SPR1 SPR0 Bit Number Bit Mnemonic Description 7 SPR2 SPI Rate Bit 2 Refer to Table 121 for bit rate description. 6 SPEN SPI Enable Bit Set to enable the SPI interface. Clear to disable the SPI interface. 5 SSDIS Slave Select Input Disable Bit Set to disable SS in both master and slave modes. In slave mode this bit has no effect if CPHA = 0. Clear to enable SS in both master and slave modes. 4 MSTR Master Mode Select Set to select the master mode. Clear to select the slave mode. 3 CPOL 2 CPHA SPI Clock Polarity Bit(1) Set to have the clock output set to high level in idle state. Clear to have the clock output set to low level in idle state. SPI Clock Phase Bit Set to have the data sampled when the clock returns to idle state (see CPOL). Clear to have the data sampled when the clock leaves the idle state (see CPOL). 155 4109J–8051–10/06 Bit Number 1-0 Bit Mnemonic Description SPR1:0 SPI Rate Bits 0 and 1 Refer to Table 121 for bit rate description. Reset Value = 0001 0100b Note: 1. When the SPI is disabled, SCK outputs high level. Table 123. SPSTA Register SPSTA (S:C4h) – SPI Status Register 7 6 5 4 3 2 1 0 SPIF WCOL - MODF - - - - Bit Number Bit Mnemonic Description 7 SPIF 6 WCOL 5 - 4 MODF 3-0 - SPI Interrupt Flag Set by hardware when an 8-bit shift is completed. Cleared by hardware when reading or writing SPDAT after reading SPSTA. Write Collision Flag Set by hardware to indicate that a collision has been detected. Cleared by hardware to indicate that no collision has been detected. Reserved The value read from this bit is indeterminate. Do not set this bit. Mode Fault Set by hardware to indicate that the SS pin is at an appropriate level. Cleared by hardware to indicate that the SS pin is at an inappropriate level. Reserved The value read from these bits is indeterminate. Do not set these bits. Reset Value = 00000 0000b Table 124. SPDAT Register SPDAT (S:C5h) – Synchronous Serial Data Register 7 6 5 4 3 2 1 0 SPD7 SPD6 SPD5 SPD4 SPD3 SPD2 SPD1 SPD0 Bit Number 7-0 Bit Mnemonic Description SPD7:0 Synchronous Serial Data. Reset Value = XXXX XXXXb 156 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 19. Two-wire Interface (TWI) Controller The AT8xC51SND1C implements a TWI controller supporting the four standard master and slave modes with multimaster capability. Thus, it allows connection of slave devices like LCD controller, audio DAC, etc., but also external master controlling where the AT8xC51SND1C is used as a peripheral of a host. The TWI bus is a bi-directional TWI serial communication standard. It is designed primarily for simple but efficient integrated circuit control. The system is comprised of 2 lines, SCL (Serial Clock) and SDA (Serial Data) that carry information between the ICs connected to them. The serial data transfer is limited to 100 Kbit/s in low speed mode, however, some higher bit rates can be achieved depending on the oscillator frequency. Various communication configurations can be designed using this bus. Figure 19-1 shows a typical TWI bus configuration using the AT8xC51SND1C in master and slave modes. All the devices connected to the bus can be master and slave. Figure 19-1. Typical TWI Bus Configuration AT8xC51SND1C Master/Slave LCD Display Rp Audio DAC Rp P1.6/SCL P1.7/SDA 19.1 HOST Microprocessor SCL SDA Description The CPU interfaces to the TWI logic via the following four 8-bit special function registers: the Synchronous Serial Control register (SSCON SFR, see Table 132), the Synchronous Serial Data register (SSDAT SFR, see Table 134), the Synchronous Serial Status register (SSSTA SFR, see Table 133) and the Synchronous Serial Address register (SSADR SFR, see Table 135). SSCON is used to enable the controller, to program the bit rate (see Table 132), to enable slave modes, to acknowledge or not a received data, to send a START or a STOP condition on the TWI bus, and to acknowledge a serial interrupt. A hardware reset disables the TWI controller. SSSTA contains a status code which reflects the status of the TWI logic and the TWI bus. The three least significant bits are always zero. The five most significant bits contains the status code. There are 26 possible status codes. When SSSTA contains F8h, no relevant state information is available and no serial interrupt is requested. A valid status code is available in SSSTA after SSI is set by hardware and is still present until SSI has been reset by software. Table 126 to Table 19-6 give the status for both master and slave modes and miscellaneous states. SSDAT contains a Byte of serial data to be transmitted or a Byte which has just been received. It is addressable while it is not in process of shifting a Byte. This occurs when TWI logic is in a defined state and the serial interrupt flag is set. Data in SSDAT remains stable as long as SSI is set. While data is being shifted out, data on the bus is simultaneously shifted in; SSDAT always contains the last Byte present on the bus. SSADR may be loaded with the 7 - bit slave address (7 most significant bits) to which the controller will respond when programmed as a slave transmitter or receiver. The LSB is used to enable general call address (00h) recognition. Figure 19-2 shows how a data transfer is accomplished on the TWI bus. 157 4109J–8051–10/06 Figure 19-2. Complete Data Transfer on TWI Bus SDA MSB Slave Address SCL 1 R/W ACK direction signal bit from receiver 2 8 Nth data Byte 9 S 1 2 ACK signal from receiver 8 9 Clock Line Held Low While Serial Interrupts Are Serviced P/S The four operating modes are: • Master transmitter • Master receiver • Slave transmitter • Slave receiver Data transfer in each mode of operation are shown in Figure 19-3 through Figure 19-6. These figures contain the following abbreviations: A Acknowledge bit (low level at SDA) A Not acknowledge bit (high level on SDA) Data 8-bit data Byte S START condition P STOP condition MR Master Receive MT Master Transmit SLA Slave Address GCA General Call Address (00h) R Read bit (high level at SDA) W Write bit (low level at SDA) In Figure 19-3 through Figure 19-6, circles are used to indicate when the serial interrupt flag is set. The numbers in the circles show the status code held in SSSTA. At these points, a service routine must be executed to continue or complete the serial transfer. These service routines are not critical since the serial transfer is suspended until the serial interrupt flag is cleared by software. When the serial interrupt routine is entered, the status code in SSSTA is used to branch to the appropriate service routine. For each status code, the required software action and details of the following serial transfer are given in Table 126 through Table 19-6. 19.1.1 Bit Rate The bit rate can be selected from seven predefined bit rates or from a programmable bit rate generator using the SSCR2, SSCR1, and SSCR0 control bits in SSCON (see Table 132). The predefined bit rates are derived from the peripheral clock (FPER) issued from the Clock Controller block as detailed in section "Oscillator", page 12, while bit rate generator is based on timer 1 overflow output. 158 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Table 125. Serial Clock Rates SSCRx 2 1 0 FPER = 6 MHz FPER = 8 MHz FPER = 10 MHz FPER Divided By 0 0 0 47 62.5 78.125 128 0 0 1 53.5 71.5 89.3 112 0 1 0 62.5 83 104.2(1) 96 19.1.2 (1) 0 1 1 75 100 125 1 0 0 12.5 16.5 20.83 1 0 1 100 1 1 0 200(1) 1 Note: Bit Frequency (kHz) 1 1 0.5 < ⋅ < 125 133.3 (1) 166.7 266.7(1) 0.67 < ⋅ < 166.7 (1) 80 480 (1) 60 333.3(1) (1) 0.81 < ⋅ < 208.3 30 (1) 96 ⋅ (256 – reload value Timer 1) 1. These bit rates are outside of the low speed standard specification limited to 100 kHz but can be used with high speed TWI components limited to 400 kHz. Master Transmitter Mode In the master transmitter mode, a number of data Bytes are transmitted to a slave receiver (see Figure 19-3). Before the master transmitter mode can be entered, SSCON must be initialized as follows: SSCR2 SSPE SSSTA SSSTO SSI SSAA SSCR1 SSCR0 Bit Rate 1 0 0 0 X Bit Rate Bit Rate SSCR2:0 define the serial bit rate (see Table 125). SSPE must be set to enable the controller. SSSTA, SSSTO and SSI must be cleared. The master transmitter mode may now be entered by setting the SSSTA bit. The TWI logic will now monitor the TWI bus and generate a START condition as soon as the bus becomes free. When a START condition is transmitted, the serial interrupt flag (SSI bit in SSCON) is set, and the status code in SSSTA is 08h. This status must be used to vector to an interrupt routine that loads SSDAT with the slave address and the data direction bit (SLA+W). The serial interrupt flag (SSI) must then be cleared before the serial transfer can continue. When the slave address and the direction bit have been transmitted and an acknowledgment bit has been received, SSI is set again and a number of status code in SSSTA are possible. There are 18h, 20h or 38h for the master mode and also 68h, 78h or B0h if the slave mode was enabled (SSAA = logic 1). The appropriate action to be taken for each of these status code is detailed in Table 126. This scheme is repeated until a STOP condition is transmitted. SSPE and SSCR2:0 are not affected by the serial transfer and are not referred to in Table 126. After a repeated START condition (state 10h) the controller may switch to the master receiver mode by loading SSDAT with SLA+R. 19.1.3 Master Receiver Mode In the master receiver mode, a number of data Bytes are received from a slave transmitter (see Figure 19-4). The transfer is initialized as in the master transmitter mode. When the START condition has been transmitted, the interrupt routine must load SSDAT with the 7 - bit slave address and the data direction bit (SLA+R). The serial interrupt flag (SSI) must then be cleared before the serial transfer can continue. 159 4109J–8051–10/06 When the slave address and the direction bit have been transmitted and an acknowledgment bit has been received, the serial interrupt flag is set again and a number of status code in SSSTA are possible. There are 40h, 48h or 38h for the master mode and also 68h, 78h or B0h if the slave mode was enabled (SSAA = logic 1). The appropriate action to be taken for each of these status code is detailed in Table 19-6. This scheme is repeated until a STOP condition is transmitted. SSPE and SSCR2:0 are not affected by the serial transfer and are not referred to in Table 19-6. After a repeated START condition (state 10h) the controller may switch to the master transmitter mode by loading SSDAT with SLA+W. 19.1.4 Slave Receiver Mode In the slave receiver mode, a number of data Bytes are received from a master transmitter (see Figure 19-5). To initiate the slave receiver mode, SSADR and SSCON must be loaded as follows: SSA6 SSA5 SSA4 ←⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ SSA3 SSA2 SSA1 SSA0 SSGC ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯→ Own Slave Address X The upper 7 bits are the addresses to which the controller will respond when addressed by a master. If the LSB (SSGC) is set, the controller will respond to the general call address (00h); otherwise, it ignores the general call address. SSCR2 SSPE SSSTA SSSTO SSI SSAA SSCR1 SSCR0 X 1 0 0 0 1 X X SSCR2:0 have no effect in the slave mode. SSPE must be set to enable the controller. The SSAA bit must be set to enable the own slave address or the general call address acknowledgment. SSSTA, SSSTO and SSI must be cleared. When SSADR and SSCON have been initialized, the controller waits until it is addressed by its own slave address followed by the data direction bit which must be logic 0 (W) for operating in the slave receiver mode. After its own slave address and the W bit has been received, the serial interrupt flag is set and a valid status code can be read from SSSTA. This status code is used to vector to an interrupt service routine, and the appropriate action to be taken for each of these status code is detailed in Table 19-6 and Table 130. The slave receiver mode may also be entered if arbitration is lost while the controller is in the master mode (see states 68h and 78h). If the SSAA bit is reset during a transfer, the controller will return a not acknowledge (logic 1) to SDA after the next received data Byte. While SSAA is reset, the controller does not respond to its own slave address. However, the TWI bus is still monitored and address recognition may be resumed at any time by setting SSAA. This means that the SSAA bit may be used to temporarily isolate the controller from the TWI bus. 19.1.5 Slave Transmitter Mode In the slave transmitter mode, a number of data Bytes are transmitted to a master receiver (see Figure 19-6). Data transfer is initialized as in the slave receiver mode. When SSADR and SSCON have been initialized, the controller waits until it is addressed by its own slave address followed by the data direction bit which must be logic 1 (R) for operating in the slave transmitter mode. After its own slave address and the R bit have been received, the serial interrupt flag is set and a valid status code can be read from SSSTA. This status code is used to vector to an interrupt service routine, and the appropriate action to be taken for each of these status code is detailed in Table 130. The slave transmitter mode may also be entered if arbitration is lost while the controller is in the master mode (see state B0h). 160 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C If the SSAA bit is reset during a transfer, the controller will transmit the last Byte of the transfer and enter state C0h or C8h. The controller is switched to the not addressed slave mode and will ignore the master receiver if it continues the transfer. Thus the master receiver receives all 1’s as serial data. While SSAA is reset, the controller does not respond to its own slave address. However, the TWI bus is still monitored and address recognition may be resumed at any time by setting SSAA. This means that the SSAA bit may be used to temporarily isolate the controller from the TWI bus. 19.1.6 Miscellaneous States There are 2 SSSTA codes that do not correspond to a defined TWI hardware state (see Table 131). These are discussed below. Status F8h indicates that no relevant information is available because the serial interrupt flag is not yet set. This occurs between other states and when the controller is not involved in a serial transfer. Status 00h indicates that a bus error has occurred during a serial transfer. A bus error is caused when a START or a STOP condition occurs at an illegal position in the format frame. Examples of such illegal positions are during the serial transfer of an address Byte, a data Byte, or an acknowledge bit. When a bus error occurs, SSI is set. To recover from a bus error, the SSSTO flag must be set and SSI must be cleared. This causes the controller to enter the not addressed slave mode and to clear the SSSTO flag (no other bits in S1CON are affected). The SDA and SCL lines are released and no STOP condition is transmitted. Note: The TWI controller interfaces to the external TWI bus via 2 port 1 pins: P1.6/SCL (serial clock line) and P1.7/SDA (serial data line). To avoid low level asserting and conflict on these lines when the TWI controller is enabled, the output latches of P1.6 and P1.7 must be set to logic 1. 161 4109J–8051–10/06 Figure 19-3. Format and States in the Master Transmitter Mode MT Successful transmission to a slave receiver S SLA W A 08h Data 18h A P 28h Next transfer started with a repeated start condition S SLA W 10h R Not acknowledge received after the slave address A P MR 20h Not acknowledge received after a data Byte A P 30h Arbitration lost in slave address or data Byte A or A Other master continues 38h Arbitration lost and addressed as slave A From slave to master 162 Data nnh Other master continues 38h Other master continues 68h 78h B0h From master to slave A or A A To corresponding states in slave mode Any number of data Bytes and their associated acknowledge bits This number (contained in SSSTA) corresponds to a defined state of the TWI bus AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 19-4. Format and States in the Master Receiver Mode MR Successful reception from a slave transmitter S SLA 08h R A Data A 40h 50h Data A P 58h Next transfer started with a repeated start condition S SLA R 10h W Not acknowledge received after the slave address A P MT 48h Arbitration lost in slave address or data Byte A or A Other master continues 38h Arbitration lost and addressed as slave A From slave to master Data nnh Other master continues 38h Other master continues 68h 78h B0h From master to slave A A To corresponding states in slave mode Any number of data Bytes and their associated acknowledge bits This number (contained in SSSTA) corresponds to a defined state of the TWI bus 163 4109J–8051–10/06 Figure 19-5. Format and States in the Slave Receiver Mode Reception of the own slave address and one or more data Bytes. All are acknowledged S SLA W A Data 60h A Data 80h Last data Byte received is not acknowledged A P or S 80h A0h A P or S 88h Arbitration lost as master and addressed as slave A 68h Reception of the general call address and one or more data Bytes General Call A Data 70h Last data Byte received is not acknowledged A 90h Data A P or S 90h A0h A P or S 98h Arbitration lost as master and addressed as slave by general call A 78h From master to slave From slave to master 164 Data nnh A Any number of data Bytes and their associated acknowledge bits This number (contained in SSSTA) corresponds to a defined state of the TWI bus AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Figure 19-6. Format and States in the Slave Transmitter Mode Reception of the own slave address and transmission of one or more data Bytes. S SLA R A Data A8h Arbitration lost as master and addressed as slave A B8h Data A P or S C0h A B0h Last data Byte transmitted. Switched to not addressed slave (SSAA = 0). A All 1’s P or S C8h From master to slave From slave to master Data nnh A Any number of data Bytes and their associated acknowledge bits This number (contained in SSSTA) corresponds to a defined state of the TWI bus 165 4109J–8051–10/06 Table 126. Status for Master Transmitter Mode Application Software Response Status Code SSSTA To SSCON Status of the TWI Bus and TWI Hardware To/From SSDAT SSSTA SSSTO SSI SSAA Next Action Taken by TWI Hardware 08h A START condition has Write SLA+W been transmitted X 0 0 X Write SLA+W X 0 0 X 10h A repeated START condition has been transmitted Write SLA+R X 0 0 X Write data Byte 0 0 0 X No SSDAT action 1 0 0 X No SSDAT action 0 1 0 X STOP condition will be transmitted and SSSTO flag will be reset. No SSDAT action 1 1 0 X STOP condition followed by a START condition will be transmitted and SSSTO flag will be reset. Write data Byte 0 0 0 X No SSDAT action 1 0 0 X No SSDAT action 0 1 0 X STOP condition will be transmitted and SSSTO flag will be reset. No SSDAT action 1 1 0 X STOP condition followed by a START condition will be transmitted and SSSTO flag will be reset. Write data Byte 0 0 0 X No SSDAT action 1 0 0 X No SSDAT action 0 1 0 X STOP condition will be transmitted and SSSTO flag will be reset. No SSDAT action 1 1 0 X STOP condition followed by a START condition will be transmitted and SSSTO flag will be reset. Write data Byte 0 0 0 X No SSDAT action 1 0 0 X No SSDAT action 0 1 0 X STOP condition will be transmitted and SSSTO flag will be reset. No SSDAT action 1 1 0 X STOP condition followed by a START condition will be transmitted and SSSTO flag will be reset. No SSDAT action 0 0 0 X TWI bus will be released and not addressed slave mode will be entered. No SSDAT action 1 0 0 X A START condition will be transmitted when the bus becomes free. 18h 20h 28h 30h 38h 166 SLA+W has been transmitted; ACK has been received SLA+W has been transmitted; NOT ACK has been received Data Byte has been transmitted; ACK has been received Data Byte has been transmitted; NOT ACK has been received Arbitration lost in SLA+W or data Bytes SLA+W will be transmitted. SLA+W will be transmitted. SLA+R will be transmitted. Logic will switch to master receiver mode Data Byte will be transmitted. Repeated START will be transmitted. Data Byte will be transmitted. Repeated START will be transmitted. Data Byte will be transmitted. Repeated START will be transmitted. Data Byte will be transmitted. Repeated START will be transmitted. AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Table 127. Status for Master Receiver Mode Application Software Response Status Code SSSTA To SSCON Status of the TWI Bus and TWI Hardware To/From SSDAT SSSTA SSSTO SSI SSAA Next Action Taken by TWI Hardware 08h A START condition has Write SLA+R been transmitted X 0 0 X Write SLA+R X 0 0 X 10h A repeated START condition has been transmitted Write SLA+W X 0 0 X SLA+W will be transmitted. Logic will switch to master transmitter mode. Arbitration lost in SLA+R or NOT ACK bit No SSDAT action 0 0 0 X TWI bus will be released and not addressed slave mode will be entered. No SSDAT action 1 0 0 X A START condition will be transmitted when the bus becomes free. SLA+R has been transmitted; ACK has been received No SSDAT action 0 0 0 0 Data Byte will be received and NOT ACK will be returned. No SSDAT action 0 0 0 1 Data Byte will be received and ACK will be returned. No SSDAT action 1 0 0 X No SSDAT action 0 1 0 X STOP condition will be transmitted and SSSTO flag will be reset. No SSDAT action 1 1 0 X STOP condition followed by a START condition will be transmitted and SSSTO flag will be reset. Read data Byte 0 0 0 0 Data Byte will be received and NOT ACK will be returned. Read data Byte 0 0 0 1 Data Byte will be received and ACK will be returned. Read data Byte 1 0 0 X Read data Byte 0 1 0 X STOP condition will be transmitted and SSSTO flag will be reset. Read data Byte 1 1 0 X STOP condition followed by a START condition will be transmitted and SSSTO flag will be reset. 38h 40h 48h 50h 58h SLA+R has been transmitted; NOT ACK has been received Data Byte has been received; ACK has been returned Data Byte has been received; NOT ACK has been returned SLA+R will be transmitted. SLA+R will be transmitted. Repeated START will be transmitted. Repeated START will be transmitted. 167 4109J–8051–10/06 Table 128. Status for Slave Receiver Mode with Own Slave Address Application Software Response Status Code SSSTA 60h 68h 80h 88h To SSCON Status of the TWI Bus and TWI Hardware To/From SSDAT Own SLA+W has been received; ACK has been returned Arbitration lost in SLA+R/W as master; own SLA+W has been received; ACK has been returned Previously addressed with own SLA+W; data has been received; ACK has been returned Previously addressed with own SLA+W; data has been received; NOT ACK has been returned SSSTA SSSTO SSI SSAA No SSDAT action X 0 0 0 Data Byte will be received and NOT ACK will be returned. No SSDAT action X 0 0 1 Data Byte will be received and ACK will be returned. No SSDAT action X 0 0 0 Data Byte will be received and NOT ACK will be returned. No SSDAT action X 0 0 1 Data Byte will be received and ACK will be returned. Read data Byte X 0 0 0 Data Byte will be received and NOT ACK will be returned. Read data Byte X 0 0 1 Data Byte will be received and ACK will be returned. Read data Byte 0 0 0 0 Read data Byte 0 0 0 1 Read data Byte Read data Byte A0h A STOP condition or repeated START condition has been received while still addressed as slave 1 0 0 0 0 0 1 No SSDAT action 0 0 0 0 No SSDAT action 0 0 0 1 No SSDAT action No SSDAT action 168 1 1 1 0 0 0 0 0 1 Next Action Taken by TWI Hardware Switched to the not addressed slave mode; no recognition of own SLA or GCA. Switched to the not addressed slave mode; own SLA will be recognized; GCA will be recognized if SSGC = logic 1. Switched to the not addressed slave mode; no recognition of own SLA or GCA. A START condition will be transmitted when the bus becomes free. Switched to the not addressed slave mode; own SLA will be recognized; GCA will be recognized if SSGC = logic 1. A START condition will be transmitted when the bus becomes free. Switched to the not addressed slave mode; no recognition of own SLA or GCA. Switched to the not addressed slave mode; own SLA will be recognized; GCA will be recognized if SSGC = logic 1. Switched to the not addressed slave mode; no recognition of own SLA or GCA. A START condition will be transmitted when the bus becomes free. Switched to the not addressed slave mode; own SLA will be recognized; GCA will be recognized if SSGC = logic 1. A START condition will be transmitted when the bus becomes free. AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Table 129. Status for Slave Receiver Mode with General Call Address Application Software Response Status Code SSSTA 70h 78h 90h 98h To SSCON Status of the TWI Bus and TWI Hardware To/From SSDAT General call address has been received; ACK has been returned Arbitration lost in SLA+R/W as master; general call address has been received; ACK has been returned Previously addressed with general call; data has been received; ACK has been returned Previously addressed with general call; data has been received; NOT ACK has been returned SSSTA SSSTO SSI SSAA No SSDAT action X 0 0 0 Data Byte will be received and NOT ACK will be returned. No SSDAT action X 0 0 1 Data Byte will be received and ACK will be returned. No SSDAT action X 0 0 0 Data Byte will be received and NOT ACK will be returned. No SSDAT action X 0 0 1 Data Byte will be received and ACK will be returned. Read data Byte X 0 0 0 Data Byte will be received and NOT ACK will be returned. Read data Byte X 0 0 1 Data Byte will be received and ACK will be returned. Read data Byte 0 0 0 0 Read data Byte 0 0 0 1 Read data Byte Read data Byte A0h A STOP condition or repeated START condition has been received while still addressed as slave 1 1 0 0 0 0 0 1 No SSDAT action 0 0 0 0 No SSDAT action 0 0 0 1 No SSDAT action No SSDAT action 1 1 0 0 0 0 0 1 Next Action Taken by TWI Hardware Switched to the not addressed slave mode; no recognition of own SLA or GCA. Switched to the not addressed slave mode; own SLA will be recognized; GCA will be recognized if SSGC = logic 1. Switched to the not addressed slave mode; no recognition of own SLA or GCA. A START condition will be transmitted when the bus becomes free. Switched to the not addressed slave mode; own SLA will be recognized; GCA will be recognized if SSGC = logic 1. A START condition will be transmitted when the bus becomes free. Switched to the not addressed slave mode; no recognition of own SLA or GCA. Switched to the not addressed slave mode; own SLA will be recognized; GCA will be recognized if SSGC = logic 1. Switched to the not addressed slave mode; no recognition of own SLA or GCA. A START condition will be transmitted when the bus becomes free. Switched to the not addressed slave mode; own SLA will be recognized; GCA will be recognized if SSGC = logic 1. A START condition will be transmitted when the bus becomes free. 169 4109J–8051–10/06 Table 130. Status for Slave Transmitter Mode Application Software Response Status Code SSSTA A8h B0h B8h C0h Status of the TWI Bus and TWI Hardware To SSCON To/From SSDAT Own SLA+R has been received; ACK has been returned Arbitration lost in SLA+R/W as master; own SLA+R has been received; ACK has been returned Data Byte in SSDAT has been transmitted; ACK has been received Data Byte in SSDAT has been transmitted; NOT ACK has been received SSSTA SSSTO SSI SSAA Write data Byte X 0 0 0 Last data Byte will be transmitted. Write data Byte X 0 0 1 Data Byte will be transmitted. Write data Byte X 0 0 0 Last data Byte will be transmitted. Write data Byte X 0 0 1 Data Byte will be transmitted. Write data Byte X 0 0 0 Last data Byte will be transmitted. Write data Byte X 0 0 1 Data Byte will be transmitted. No SSDAT action 0 0 0 0 No SSDAT action 0 0 0 1 No SSDAT action No SSDAT action C8h Last data Byte in SSDAT has been transmitted (SSAA= 0); ACK has been received 1 1 0 0 0 0 0 1 No SSDAT action 0 0 0 0 No SSDAT action 0 0 0 1 No SSDAT action No SSDAT action 1 1 0 0 0 0 0 1 Next Action Taken by TWI Hardware Switched to the not addressed slave mode; no recognition of own SLA or GCA. Switched to the not addressed slave mode; own SLA will be recognized; GCA will be recognized if SSGC = logic 1. Switched to the not addressed slave mode; no recognition of own SLA or GCA. A START condition will be transmitted when the bus becomes free. Switched to the not addressed slave mode; own SLA will be recognized; GCA will be recognized if SSGC = logic 1. A START condition will be transmitted when the bus becomes free. Switched to the not addressed slave mode; no recognition of own SLA or GCA. Switched to the not addressed slave mode; own SLA will be recognized; GCA will be recognized if SSGC = logic 1. Switched to the not addressed slave mode; no recognition of own SLA or GCA. A START condition will be transmitted when the bus becomes free. Switched to the not addressed slave mode; own SLA will be recognized; GCA will be recognized if SSGC = logic 1. A START condition will be transmitted when the bus becomes free. Table 131. Status for Miscellaneous States Application Software Response Status Code SSSTA To SSCON Status of the TWI Bus and TWI Hardware To/From SSDAT F8h No relevant state information available; SSI = 0 No SSDAT action 00h Bus error due to an illegal START or STOP condition No SSDAT action 170 SSSTA SSSTO SSI SSAA No SSCON action 0 1 0 Next Action Taken by TWI Hardware Wait or proceed current transfer. X Only the internal hardware is affected, no STOP condition is sent on the bus. In all cases, the bus is released and SSSTO is reset. AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 19.2 Registers Table 132. SSCON Register SSCON (S:93h) – Synchronous Serial Control Register 7 6 5 4 3 2 1 0 SSCR2 SSPE SSSTA SSSTO SSI SSAA SSCR1 SSCR0 Bit Number Bit Mnemonic Description Synchronous Serial Control Rate Bit 2 Refer to Table 125 for rate description. 7 SSCR2 6 SSPE Synchronous Serial Peripheral Enable Bit Set to enable the controller. Clear to disable the controller. 5 SSSTA Synchronous Serial Start Flag Set to send a START condition on the bus. Clear not to send a START condition on the bus. 4 SSSTO Synchronous Serial Stop Flag Set to send a STOP condition on the bus. Clear not to send a STOP condition on the bus. 3 SSI Synchronous Serial Interrupt Flag Set by hardware when a serial interrupt is requested. Must be cleared by software to acknowledge interrupt. Synchronous Serial Assert Acknowledge Flag Set to enable slave modes. Slave modes are entered when SLA or GCA (if SSGC set) is recognized. Clear to disable slave modes. Master Receiver Mode in progress Clear to force a not acknowledge (high level on SDA). Set to force an acknowledge (low level on SDA). Master Transmitter Mode in progress This bit has no specific effect when in master transmitter mode. Slave Receiver Mode in progress Clear to force a not acknowledge (high level on SDA). Set to force an acknowledge (low level on SDA). Slave Transmitter Mode in progress Clear to isolate slave from the bus after last data Byte transmission. Set to enable slave mode. 2 SSAA 1 SSCR1 Synchronous Serial Control Rate Bit 1 Refer to Table 125 for rate description. 0 SSCR0 Synchronous Serial Control Rate Bit 0 Refer to Table 125 for rate description. Reset Value = 0000 0000b Table 133. SSSTA Register SSSTA (S:94h) – Synchronous Serial Status Register 7 6 5 4 3 2 1 0 SSC4 SSC3 SSC2 SSC1 SSC0 0 0 0 171 4109J–8051–10/06 Bit Number Bit Mnemonic Description 7:3 SSC4:0 2:0 0 Synchronous Serial Status Code Bits 0 to 4 Refer to Table 126 to Table 19-6 for status description. Always 0. Reset Value = F8h Table 134. SSDAT Register SSDAT (S:95h) – Synchronous Serial Data Register 7 6 5 4 3 2 1 0 SSD7 SSD6 SSD5 SSD4 SSD3 SSD2 SSD1 SSD0 Bit Number Bit Mnemonic Description 7:1 SSD7:1 Synchronous Serial Address bits 7 to 1 or Synchronous Serial Data Bits 7 to 1 0 SSD0 Synchronous Serial Address bit 0 (R/W) or Synchronous Serial Data Bit 0 Reset Value = 1111 1111b Table 135. SSADR Register SSADR (S:96h) – Synchronous Serial Address Register 7 6 5 4 3 2 1 0 SSA7 SSA6 SSA5 SSA4 SSA3 SSA2 SSA1 SSGC Bit Number Bit Mnemonic Description 7:1 SSA7:1 Synchronous Serial Slave Address Bits 7 to 1 0 SSGC Synchronous Serial General Call Bit Set to enable the general call address recognition. Clear to disable the general call address recognition. Reset Value = 1111 1110b 172 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 20. Analog to Digital Converter The AT8xC51SND1C implement a 2-channel 10-bit (8 true bits) analog to digital converter (ADC). First channel of this ADC can be used for battery monitoring while the second one can be used for voice sampling at 8 kHz. 20.1 Description The A/D converter interfaces with the C51 core through four special function registers: ADCON, the ADC control register (see Table 137); ADDH and ADDL, the ADC data registers (see Table 139 and Table 140); and ADCLK, the ADC clock register (see Table 138). As shown in Figure 20-1, the ADC is composed of a 10-bit cascaded potentiometric digital to analog converter, connected to the negative input of a comparator. The output voltage of this DAC is compared to the analog voltage stored in the Sample and Hold and coming from AIN0 or AIN1 input depending on the channel selected (see Table 136). The 10-bit ADDAT converted value (see formula in Figure 20-1) is delivered in ADDH and ADDL registers, ADDH is giving the 8 most significant bits while ADDL is giving the 2 least significant bits. ADDAT Figure 20-1. ADC Structure ADCON.5 ADCON.3 ADEN ADSST ADC Interrupt Request ADCON.4 ADEOC ADC CLOCK CONTROL EADC IEN1.3 AIN1 0 AIN0 1 8 ADDH 2 ADDL + SAR AVSS ADCS Sample and Hold 10 ADCON.0 R/2R DAC 1023 ⋅ V IN ADDAT = -------------------------VREF AREFP AREFN Figure 20-2 shows the timing diagram of a complete conversion. For simplicity, the figure depicts the waveforms in idealized form and do not provide precise timing information. For ADC characteristics and timing parameters refer to the section “AC Characteristics”. 173 4109J–8051–10/06 Figure 20-2. Timing Diagram CLK TADCLK ADEN TSETUP ADSST TCONV ADEOC 20.1.1 Clock Generator The ADC clock is generated by division of the peripheral clock (see details in section “X2 Feature”, page 12). The division factor is then given by ADCP4:0 bits in ADCLK register. Figure 203 shows the ADC clock generator and its calculation formula(1). Figure 20-3. ADC Clock Generator and Symbol Caution: ADCLK PER CLOCK ÷2 ADCD4:0 ADC CLOCK ADC Clock ADC Clock Symbol PERclk ADCclk = ------------------------2 ⋅ ADCD Note: 1. In all cases, the ADC clock frequency may be higher than the maximum FADCLK parameter reported in the section “Analog to Digital Converter”, page 198. 2. The ADCD value of 0 is equivalent to an ADCD value of 32. 20.1.2 Channel Selection The channel on which conversion is performed is selected by the ADCS bit in ADCON register according to Table 136. Table 136. ADC Channel Selection 20.1.3 ADCS Channel 0 AIN1 1 AIN0 Conversion Precision The 10-bit precision conversion is achieved by stopping the CPU core activity during conversion for limiting the digital noise induced by the core. This mode called the Pseudo-Idle mode(1),(2) is enabled by setting the ADIDL bit in ADCON register(3). Thus, when conversion is launched (see Section "Conversion Launching", page 175), the CPU core is stopped until the end of the con- 174 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C version (see Section "End Of Conversion", page 175). This bit is cleared by hardware at the end of the conversion. Notes: 20.1.4 1. Only the CPU activity is frozen, peripherals are not affected by the Pseudo-Idle mode. 2. If some interrupts occur during the Pseudo-Idle mode, they will be delayed and processed, according to their priority after the end of the conversion. 3. Concurrently with ADSST bit. Configuration The ADC configuration consists in programming the ADC clock as detailed in the Section "Clock Generator", page 174. The ADC is enabled using the ADEN bit in ADCON register. As shown in Figure 93, user must wait the setup time (TSETUP) before launching any conversion. Figure 20-4. ADC Configuration Flow ADC Configuration Program ADC Clock ADCD4:0 = xxxxxb Enable ADC ADIDL = x ADEN = 1 Wait Setup Time 20.1.5 Conversion Launching The conversion is launched by setting the ADSST bit in ADCON register, this bit remains set during the conversion. As soon as the conversion is started, it takes 11 clock periods (TCONV) before the data is available in ADDH and ADDL registers. Figure 20-5. ADC Conversion Launching Flow ADC Conversion Start Select Channel ADCS = 0-1 Start Conversion ADSST = 1 20.1.6 End Of Conversion The end of conversion is signalled by the ADEOC flag in ADCON register becoming set or by the ADSST bit in ADCON register becoming cleared. ADEOC flag can generate an interrupt if 175 4109J–8051–10/06 enabled by setting EADC bit in IEN1 register. This flag is set by hardware and must be reset by software. 20.2 Registers Table 137. ADCON Register ADCON (S:F3h) – ADC Control Register 7 6 5 4 3 2 1 0 - ADIDL ADEN ADEOC ADSST - - ADCS Bit Number Bit Mnemonic Description Reserved The value read from this bit is always 0. Do not set this bit. 7 - 6 ADIDL ADC Pseudo-Idle Mode Set to suspend the CPU core activity (pseudo-idle mode) during conversion. Clear by hardware at the end of conversion. 5 ADEN ADC Enable Bit Set to enable the A to D converter. Clear to disable the A to D converter and put it in low power stand by mode. 4 ADEOC End Of Conversion Flag Set by hardware when ADC result is ready to be read. This flag can generate an interrupt. Must be cleared by software. 3 ADSST Start and Status Bit Set to start an A to D conversion on the selected channel. Cleared by hardware at the end of conversion. 2-1 - 0 ADCS Reserved The value read from these bits is always 0. Do not set these bits. Channel Selection Bit Set to select channel 0 for conversion. Clear to select channel 1 for conversion. Reset Value = 0000 0000b Table 138. ADCLK Register ADCLK (S:F2h) – ADC Clock Divider Register 7 6 5 4 3 2 1 0 - - - ADCD4 ADCD3 ADCD2 ADCD1 ADCD0 Bit Number Bit Mnemonic Description 7-5 - 4-0 ADCD4:0 Reserved The value read from these bits is always 0. Do not set these bits. ADC Clock Divider 5-bit divider for ADC clock generation. Reset Value = 0000 0000b 176 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Table 139. ADDH Register ADDH (S:F5h Read Only) – ADC Data High Byte Register 7 6 5 4 3 2 1 0 ADAT9 ADAT8 ADAT7 ADAT6 ADAT5 ADAT4 ADAT3 ADAT2 Bit Number 7-0 Bit Mnemonic Description ADAT9:2 ADC Data 8 Most Significant Bits of the 10-bit ADC data. Reset Value = 0000 0000b Table 140. ADDL Register ADDL (S:F4h Read Only) – ADC Data Low Byte Register 7 6 5 4 3 2 1 0 - - - - - - ADAT1 ADAT0 Bit Number Bit Mnemonic Description 7-2 - 1-0 ADAT1:0 Reserved The value read from these bits is always 0. Do not set these bits. ADC Data 2 Least Significant Bits of the 10-bit ADC data. Reset Value = 0000 0000b 177 4109J–8051–10/06 21. Keyboard Interface The AT8xC51SND1C implement a keyboard interface allowing the connection of a 4 x n matrix keyboard. It is based on 4 inputs with programmable interrupt capability on both high or low level. These inputs are available as alternate function of P1.3:0 and allow exit from idle and power down modes. 21.1 Description The keyboard interfaces with the C51 core through 2 special function registers: KBCON, the keyboard control register (see Table 141); and KBSTA, the keyboard control and status register (see Table 142). The keyboard inputs are considered as 4 independent interrupt sources sharing the same interrupt vector. An interrupt enable bit (EKB in IEN1 register) allows global enable or disable of the keyboard interrupt (see Figure 21-1). As detailed in Figure 21-2 each keyboard input has the capability to detect a programmable level according to KINL3:0 bit value in KBCON register. Level detection is then reported in interrupt flags KINF3:0 in KBSTA register. A keyboard interrupt is requested each time one of the four flags is set, i.e. the input level matches the programmed one. Each of these four flags can be masked by software using KINM3:0 bits in KBCON register and is cleared by reading KBSTA register. This structure allows keyboard arrangement from 1 by n to 4 by n matrix and allow usage of KIN inputs for any other purposes. Figure 21-1. Keyboard Interface Block Diagram KIN0 Input Circuitry KIN1 Input Circuitry KIN2 Input Circuitry KIN3 Input Circuitry Keyboard Interface Interrupt Request EKB IEN1.4 Figure 21-2. Keyboard Input Circuitry 0 KIN3:0 KINF3:0 1 KBSTA.3:0 KINM3:0 KINL3:0 KBCON.3:0 KBCON.7:4 21.1.1 Power Reduction Mode KIN3:0 inputs allow exit from idle and power-down modes as detailed in section “Power Management”, page 47. To enable this feature, KPDE bit in KBSTA register must be set to logic 1. Due to the asynchronous keypad detection in power down mode (all clocks are stopped), exit may happen on parasitic key press. In this case, no key is detected and software must enter power down again. 21.2 Registers Table 141. KBCON Register 178 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C KBCON (S:A3h) – Keyboard Control Register 7 6 5 4 3 2 1 0 KINL3 KINL2 KINL1 KINL0 KINM3 KINM2 KINM1 KINM0 Bit Number Bit Mnemonic Description 7-4 KINL3:0 Keyboard Input Level Bit Set to enable a high level detection on the respective KIN3:0 input. Clear to enable a low level detection on the respective KIN3:0 input. 3-0 KINM3:0 Keyboard Input Mask Bit Set to prevent the respective KINF3:0 flag from generating a keyboard interrupt. Clear to allow the respective KINF3:0 flag to generate a keyboard interrupt. Reset Value = 0000 1111b 21.2.0.1 Table 142. KBSTA Register KBSTA (S:A4h) – Keyboard Control and Status Register 7 6 5 4 3 2 1 0 KPDE - - - KINF3 KINF2 KINF1 KINF0 Bit Number Bit Mnemonic Description 7 KPDE 6-4 - 3-0 KINF3:0 Keyboard Power Down Enable Bit Set to enable exit of power down mode by the keyboard interrupt. Clear to disable exit of power down mode by the keyboard interrupt. Reserved The value read from these bits is always 0. Do not set these bits. Keyboard Input Interrupt Flag Set by hardware when the respective KIN3:0 input detects a programmed level. Cleared when reading KBSTA. Reset Value = 0000 0000b 179 4109J–8051–10/06 22. Electrical Characteristics 22.1 Absolute Maximum Rating Storage Temperature ......................................... -65 to +150°C Voltage on any other Pin to VSS .................................... -0.3 *NOTICE: to +4.0 V IOL per I/O Pin ................................................................. 5 mA Power Dissipation ............................................................. 1 W Stressing the device beyond the “Absolute Maximum Ratings” may cause permanent damage. These are stress ratings only. Operation beyond the “operating conditions” is not recommended and extended exposure beyond the “Operating Conditions” may affect device reliability. Operating Conditions Ambient Temperature Under Bias........................ -40 to +85°C VDD ........................................................................................................................ 4.0V 22.2 DC Characteristics 22.2.1 Digital Logic Table 143. Digital DC Characteristics VDD = 2.7 to 3.3 V, TA = -40 to +85°C Symbol VIL VIH1 (2) Parameter Min Input Low Voltage Input High Voltage (except RST, X1) Typ(1) Max Units -0.5 0.2·VDD - 0.1 V 0.2·VDD + 1.1 VDD V 0.7·VDD VDD + 0.5 V Test Conditions VIH2 Input High Voltage (RST, X1) VOL1 Output Low Voltage (except P0, ALE, MCMD, MDAT, MCLK, SCLK, DCLK, DSEL, DOUT) 0.45 V IOL= 1.6 mA VOL2 Output Low Voltage (P0, ALE, MCMD, MDAT, MCLK, SCLK, DCLK, DSEL, DOUT) 0.45 V IOL= 3.2 mA VOH1 Output High Voltage (P1, P2, P3, P4 and P5) VDD - 0.7 V IOH= -30 μA VOH2 Output High Voltage (P0, P2 address mode, ALE, MCMD, MDAT, MCLK, SCLK, DCLK, DSEL, DOUT, D+, D-) VDD - 0.7 V IOH= -3.2 mA IIL Logical 0 Input Current (P1, P2, P3, P4 and P5) -50 μA VIN= 0.45 V ILI Input Leakage Current (P0, ALE, MCMD, MDAT, MCLK, SCLK, DCLK, DSEL, DOUT) 10 μA 0.45< VIN< VDD ITL Logical 1 to 0 Transition Current (P1, P2, P3, P4 and P5) -650 μA VIN= 2.0 V 200 kΩ RRST CIO VRET 180 Pull-Down Resistor Pin Capacitance VDD Data Retention Limit 50 90 10 pF 1.8 TA= 25°C V AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C Table 143. Digital DC Characteristics VDD = 2.7 to 3.3 V, TA = -40 to +85°C Symbol Parameter Min AT89C51SND1C Operating Current IDD Typ(1) Max (3) X1 / X2 mode 6.5 / 10.5 8 / 13.5 9.5 / 17 AT83SND1C Operating Current X1 / X2 mode 6.5 / 10.5 8 / 13.5 9.5 / 17 AT80C51SND1C Idle Mode Current X1 / X2 mode 6.5 / 10.5 8 / 13.5 9.5 / 17 AT89C51SND1C (3) Idle Mode Current IDL IPD IFP X1 / X2 mode 5.3 / 8.1 6.4 / 10.3 7.5 / 13 Units Test Conditions VDD < 3.3 V mA 12 MHz 16 MHz 20 MHz VDD < 3.3 V mA 12 MHz 16 MHz 20 MHz VDD < 3.3 V mA 12 MHz 16 MHz 20 MHz VDD < 3.3 V mA 12 MHz 16 MHz 20 MHz VDD < 3.3 V AT83SND1C Idle Mode Current X1 / X2 mode 5.3 / 8.1 6.4 / 10.3 7.5 / 13 AT80C51SND1C Idle Mode Current X1 / X2 mode 5.3 / 8.1 6.4 / 10.3 7.5 / 13 mA mA 12 MHz 16 MHz 20 MHz VDD < 3.3 V 12 MHz 16 MHz 20 MHz AT89C51SND1C Power-Down Mode Current 20 500 μA VRET < VDD < 3.3 V AT83SND1C Power-Down Mode Current 20 500 μA VRET < VDD < 3.3 V AT80C51SND1C Power-Down Mode Current 20 500 μA VRET < VDD < 3.3 V 15 mA VDD < 3.3 V AT89C51SND1C Flash Programming Current Notes: 1. Typical values are obtained using VDD= 3 V and TA= 25°C. They are not tested and there is no guarantee on these values. 2. Flash retention is guaranteed with the same formula for VDD min down to 0V. 3. See Table 144 for typical consumption in player mode. Table 144. Typical Reference Design AT89C51SND1C Power Consumption Player Mode IDD Test Conditions Stop 10 mA AT89C51SND1C at 16 MHz, X2 mode, VDD= 3 V No song playing Playing 30 mA AT89C51SND1C at 16 MHz, X2 mode, VDD= 3 V MP3 Song with Fs= 44.1 KHz, at any bit rates (Variable Bit Rate) 181 4109J–8051–10/06 22.2.1.1 IDD, IDL and IPD Test Conditions Figure 22-1. IDD Test Condition, Active Mode VDD VDD RST (NC) Clock Signal VDD PVDD UVDD AVDD X2 X1 IDD VDD P0 VSS PVSS UVSS AVSS VSS TST All other pins are unconnected Figure 22-2. IDL Test Condition, Idle Mode VDD RST VSS (NC) Clock Signal VDD PVDD UVDD AVDD X2 X1 IDL VDD P0 VSS PVSS UVSS AVSS VSS TST All other pins are unconnected Figure 22-3. IPD Test Condition, Power-Down Mode VDD RST VSS (NC) X2 X1 VSS PVSS UVSS AVSS VSS 182 VDD PVDD UVDD AVDD IPD VDD P0 MCMD MDAT TST All other pins are unconnected AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 22.2.2 A to D Converter Table 145. A to D Converter DC Characteristics VDD = 2.7 to 3.3 V, TA = -40 to +85°C Symbol Typ Max Units Test Conditions 3.3 V 600 μA AVDD= 3.3V AIN1:0= 0 to AVDD ADEN= 1 2 μA AVDD= 3.3V ADEN= 0 or PD= 1 V Analog Supply Voltage AIDD Analog Operating Supply Current AIPD Analog Standby Current AVIN Analog Input Voltage AVSS AVDD Reference Voltage AREFN AREFP AVSS 2.4 AVDD 10 30 KΩ TA= 25°C 10 pF TA= 25°C RREF 2.7 AREF Input Resistance CIA 22.2.3.1 Min AVDD AVREF 22.2.3 Parameter V Analog Input capacitance Oscillator & Crystal Schematic Figure 22-4. Crystal Connection X1 C1 Q C2 VSS Note: 22.2.3.2 X2 For operation with most standard crystals, no external components are needed on X1 and X2. It may be necessary to add external capacitors on X1 and X2 to ground in special cases (max 10 pF). X1 and X2 may not be used to drive other circuits. Parameters Table 146. Oscillator & Crystal Characteristics VDD = 2.7 to 3.3 V, TA = -40 to +85°C Symbol Parameter Min Typ Max Unit CX1 Internal Capacitance (X1 - VSS) 10 pF CX2 Internal Capacitance (X2 - VSS) 10 pF CL Equivalent Load Capacitance (X1 - X2) 5 pF DL Drive Level 50 μW Crystal Frequency 20 MHz RS Crystal Series Resistance 40 Ω CS Crystal Shunt Capacitance 6 pF F 183 4109J–8051–10/06 22.2.4 22.2.4.1 Phase Lock Loop Schematic Figure 22-5. PLL Filter Connection FILT R C2 C1 VSS 22.2.4.2 VSS Parameters Table 147. PLL Filter Characteristics VDD = 2.7 to 3.3 V, TA = -40 to +85°C Symbol 22.2.5 22.2.5.1 Parameter Min Typ Max Unit R Filter Resistor 100 Ω C1 Filter Capacitance 1 10 nF C2 Filter Capacitance 2 2.2 nF USB Connection Schematic Figure 22-6. USB Connection VDD VBUS To Power Supply D+ RFS D+ RUSB D- D- RUSB GND VSS 22.2.5.2 Parameters Table 148. USB Characteristics VDD = 2.7 to 3.3 V, TA = -40 to +85°C Symbol 184 Parameter Min Typ Max Unit RUSB USB Termination Resistor 27 Ω RFS USB Full Speed Resistor 1.5 KΩ AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 22.2.6 22.2.6.1 In System Programming Schematic Figure 22-7. ISP Pull-Down Connection ISP RISP VSS 22.2.6.2 Parameters Table 149. ISP Pull-Down Characteristics VDD = 2.7 to 3.3 V, TA = -40 to +85°C Symbol RISP Parameter ISP Pull-Down Resistor Min Typ 2.2 Max Unit KΩ 185 4109J–8051–10/06 22.3 AC Characteristics 22.3.1 22.3.1.1 External Program Bus Cycles Definition of Symbols Table 150. External Program Bus Cycles Timing Symbol Definitions Signals 22.3.1.2 Conditions A Address H High I Instruction In L Low L ALE V Valid P PSEN X No Longer Valid Z Floating Variable Clock Standard Mode Variable Clock X2 Mode Timings Test conditions: capacitive load on all pins= 50 pF. Table 151. External Program Bus Cycle - Read AC Timings VDD = 2.7 to 3.3 V, TA = -40 to +85°C Symbol 186 Parameter TCLCL Clock Period TLHLL ALE Pulse Width TAVLL Min Max Min Max Unit 50 50 ns 2·TCLCL-15 TCLCL-15 ns Address Valid to ALE Low TCLCL-20 0.5·TCLCL-20 ns TLLAX Address hold after ALE Low TCLCL-20 0.5·TCLCL-20 ns TLLIV ALE Low to Valid Instruction 4·TCLCL-35 2·TCLCL-35 ns TPLPH PSEN Pulse Width 3·TCLCL-25 1.5·TCLCL-25 ns TPLIV PSEN Low to Valid Instruction TPXIX Instruction Hold After PSEN High TPXIZ Instruction Float After PSEN High TCLCL-10 0.5·TCLCL-10 ns TAVIV Address Valid to Valid Instruction 5·TCLCL-35 2.5·TCLCL-35 ns TPLAZ PSEN Low to Address Float 10 10 ns 3·TCLCL-35 0 1.5·TCLCL-35 0 ns ns AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 22.3.1.3 Waveforms Figure 22-8. External Program Bus Cycle - Read Waveforms ALE TLHLL TPLPH TLLPL PSEN TPLIV TPLAZ TAVLL TLLAX P0 D7:0 TPXAV TPXIZ TPXIX A7:0 D7:0 A7:0 D7:0 Instruction In P2 22.3.2 22.3.2.1 Instruction In A15:8 A15:8 External Data 8-bit Bus Cycles Definition of Symbols Table 152. External Data 8-bit Bus Cycles Timing Symbol Definitions Signals 22.3.2.2 Conditions A Address H High D Data In L Low L ALE V Valid Q Data Out X No Longer Valid R RD Z Floating W WR Timings Test conditions: capacitive load on all pins= 50 pF. Table 153. External Data 8-bit Bus Cycle - Read AC Timings VDD = 2.7 to 3.3 V, TA = -40 to +85°C Variable Clock Standard Mode Symbol Parameter TCLCL Clock Period TLHLL ALE Pulse Width TAVLL Min Max Variable Clock X2 Mode Min Max Unit 50 50 ns 2·TCLCL-15 TCLCL-15 ns Address Valid to ALE Low TCLCL-20 0.5·TCLCL-20 ns TLLAX Address hold after ALE Low TCLCL-20 0.5·TCLCL-20 ns TLLRL ALE Low to RD Low 3·TCLCL-30 1.5·TCLCL-30 ns 187 4109J–8051–10/06 Variable Clock Standard Mode Symbol Parameter TRLRH RD Pulse Width TRHLH RD high to ALE High TAVDV Address Valid to Valid Data In TAVRL Address Valid to RD Low TRLDV RD Low to Valid Data TRLAZ RD Low to Address Float TRHDX Data Hold After RD High TRHDZ Data Float After RD High Min Max 6·TCLCL-25 TCLCL-20 Variable Clock X2 Mode Min Max 3·TCLCL-25 TCLCL+20 0.5·TCLCL-20 9·TCLCL-65 4·TCLCL-30 Unit ns 0.5·TCLCL+20 ns 4.5·TCLCL-65 ns 2·TCLCL-30 ns 5·TCLCL-30 2.5·TCLCL-30 ns 0 0 ns 0 0 2·TCLCL-25 ns TCLCL-25 ns Table 154. External Data 8-bit Bus Cycle - Write AC Timings VDD = 2.7 to 3.3 V, TA = -40 to +85°C Variable Clock Standard Mode Symbol 188 Parameter TCLCL Clock Period TLHLL ALE Pulse Width TAVLL Min Max Variable Clock X2 Mode Min Max Unit 50 50 ns 2·TCLCL-15 TCLCL-15 ns Address Valid to ALE Low TCLCL-20 0.5·TCLCL-20 ns TLLAX Address hold after ALE Low TCLCL-20 0.5·TCLCL-20 ns TLLWL ALE Low to WR Low 3·TCLCL-30 1.5·TCLCL-30 ns TWLWH WR Pulse Width 6·TCLCL-25 3·TCLCL-25 ns TWHLH WR High to ALE High TAVWL Address Valid to WR Low 4·TCLCL-30 2·TCLCL-30 ns TQVWH Data Valid to WR High 7·TCLCL-20 3.5·TCLCL-20 ns TWHQX Data Hold after WR High TCLCL-15 0.5·TCLCL-15 ns TCLCL-20 TCLCL+20 0.5·TCLCL-20 0.5·TCLCL+20 ns AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 22.3.2.3 Waveforms Figure 22-9. External Data 8-bit Bus Cycle - Read Waveforms ALE TLHLL TLLRL TRLRH TRHLH RD TRLDV TRHDZ TRLAZ TAVLL P0 TLLAX TRHDX A7:0 D7:0 TAVRL Data In TAVDV P2 A15:8 Figure 22-10. External Data 8-bit Bus Cycle - Write Waveforms ALE TLHLL TLLWL TWLWH TWHLH WR TAVWL TAVLL P0 TLLAX TQVWH A7:0 TWHQX D7:0 Data Out P2 22.3.3 22.3.3.1 A15:8 External IDE 16-bit Bus Cycles Definition of Symbols Table 155. External IDE 16-bit Bus Cycles Timing Symbol Definitions Signals Conditions A Address H High D Data In L Low L ALE V Valid Q Data Out X No Longer Valid R RD Z Floating W WR 189 4109J–8051–10/06 22.3.3.2 Timings Test conditions: capacitive load on all pins= 50 pF. Table 156. External IDE 16-bit Bus Cycle - Data Read AC Timings VDD = 2.7 to 3.3 V, TA = -40 to +85°C Variable Clock Standard Mode Symbol Parameter TCLCL Clock Period TLHLL ALE Pulse Width TAVLL Min Max Variable Clock X2 Mode Min Max Unit 50 50 ns 2·TCLCL-15 TCLCL-15 ns Address Valid to ALE Low TCLCL-20 0.5·TCLCL-20 ns TLLAX Address hold after ALE Low TCLCL-20 0.5·TCLCL-20 ns TLLRL ALE Low to RD Low 3·TCLCL-30 1.5·TCLCL-30 ns TRLRH RD Pulse Width 6·TCLCL-25 3·TCLCL-25 ns TRHLH RD high to ALE High TAVDV Address Valid to Valid Data In TAVRL Address Valid to RD Low TRLDV RD Low to Valid Data TRLAZ RD Low to Address Float TRHDX Data Hold After RD High TRHDZ Data Float After RD High TCLCL-20 TCLCL+20 0.5·TCLCL-20 9·TCLCL-65 4·TCLCL-30 0.5·TCLCL+20 ns 4.5·TCLCL-65 ns 2·TCLCL-30 ns 5·TCLCL-30 2.5·TCLCL-30 ns 0 0 ns 0 0 2·TCLCL-25 ns TCLCL-25 ns Table 157. External IDE 16-bit Bus Cycle - Data Write AC Timings VDD = 2.7 to 3.3 V, TA = -40 to +85°C Variable Clock Standard Mode Symbol 190 Parameter TCLCL Clock Period TLHLL ALE Pulse Width TAVLL Min Max Variable Clock X2 Mode Min Max Unit 50 50 ns 2·TCLCL-15 TCLCL-15 ns Address Valid to ALE Low TCLCL-20 0.5·TCLCL-20 ns TLLAX Address hold after ALE Low TCLCL-20 0.5·TCLCL-20 ns TLLWL ALE Low to WR Low 3·TCLCL-30 1.5·TCLCL-30 ns TWLWH WR Pulse Width 6·TCLCL-25 3·TCLCL-25 ns TWHLH WR High to ALE High TAVWL Address Valid to WR Low 4·TCLCL-30 2·TCLCL-30 ns TQVWH Data Valid to WR High 7·TCLCL-20 3.5·TCLCL-20 ns TWHQX Data Hold after WR High TCLCL-15 0.5·TCLCL-15 ns TCLCL-20 TCLCL+20 0.5·TCLCL-20 0.5·TCLCL+20 ns AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 22.3.3.3 Waveforms Figure 22-11. External IDE 16-bit Bus Cycle - Data Read Waveforms ALE TLHLL TLLRL TRLRH TRHLH RD TRLDV TRHDZ TRLAZ TAVLL P0 TLLAX TRHDX A7:0 D7:0 TAVRL Data In TAVDV P2 D15:8(1) A15:8 Data In Note: 1. D15:8 is written in DAT16H SFR. Figure 22-12. External IDE 16-bit Bus Cycle - Data Write Waveforms ALE TLHLL TLLWL TWLWH TWHLH WR TAVWL TAVLL P0 TLLAX TQVWH A7:0 TWHQX D7:0 Data Out P2 A15:8 D15:8(1) Data Out Note: 22.4 1. D15:8 is the content of DAT16H SFR. SPI Interface 22.4.0.4 Definition of Symbols Table 158. SPI Interface Timing Symbol Definitions Signals Conditions C Clock H High I Data In L Low O Data Out V Valid X No Longer Valid Z Floating 191 4109J–8051–10/06 22.4.0.5 Timings Test conditions: capacitive load on all pins= 50 pF. Table 159. SPI Interface Master AC Timing VDD = 2.7 to 3.3 V, TA = -40 to +85°C Symbol Parameter Min Max Unit Slave Mode TCHCH Clock Period TCHCX 2 TPER Clock High Time 0.8 TPER TCLCX Clock Low Time 0.8 TPER TSLCH, TSLCL SS Low to Clock edge 100 ns TIVCL, TIVCH Input Data Valid to Clock Edge 40 ns TCLIX, TCHIX Input Data Hold after Clock Edge 40 ns TCLOV, TCHOV Output Data Valid after Clock Edge TCLOX, TCHOX Output Data Hold Time after Clock Edge 0 ns TCLSH, TCHSH SS High after Clock Edge 0 ns TSLOV SS Low to Output Data Valid 50 ns TSHOX Output Data Hold after SS High 50 ns TSHSL SS High to SS Low TILIH Input Rise Time 2 μs TIHIL Input Fall Time 2 μs TOLOH Output Rise time 100 ns TOHOL Output Fall Time 100 ns 40 ns (1) Master Mode Note: 192 TCHCH Clock Period TCHCX 2 TPER Clock High Time 0.8 TPER TCLCX Clock Low Time 0.8 TPER TIVCL, TIVCH Input Data Valid to Clock Edge 20 ns TCLIX, TCHIX Input Data Hold after Clock Edge 20 ns TCLOV, TCHOV Output Data Valid after Clock Edge TCLOX, TCHOX Output Data Hold Time after Clock Edge TILIH Input Data Rise Time 2 μs TIHIL Input Data Fall Time 2 μs TOLOH Output Data Rise time 50 ns TOHOL Output Data Fall Time 50 ns 40 0 ns ns 1. Value of this parameter depends on software. AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 22.4.0.6 Waveforms Figure 22-13. SPI Slave Waveforms (SSCPHA= 0) SS (input) TSLCH TSLCL TCHCH SCK (SSCPOL= 0) (input) TCHCX TCLCH TSHSL TCLCX TCHCL SCK (SSCPOL= 1) (input) TCLOX TCHOX TCLOV TCHOV TSLOV MISO (output) TCLSH TCHSH SLAVE MSB OUT BIT 6 TSHOX SLAVE LSB OUT (1) TIVCH TCHIX TIVCL TCLIX MOSI (input) Note: MSB IN BIT 6 LSB IN 1. Not Defined but generally the MSB of the character which has just been received. Figure 22-14. SPI Slave Waveforms (SSCPHA= 1) SS (input) TSLCH TSLCL SCK (SSCPOL= 0) (input) TCHCH TCHCX TSHSL TCLCX TCHCL SCK (SSCPOL= 1) (input) TCHOV TCLOV TSLOV MISO (output) TCLCH TCLSH TCHSH (1) SLAVE MSB OUT BIT 6 TCHOX TCLOX TSHOX SLAVE LSB OUT TIVCH TCHIX TIVCL TCLIX MOSI (input) Note: MSB IN BIT 6 LSB IN 1. Not Defined but generally the LSB of the character which has just been received. 193 4109J–8051–10/06 Figure 22-15. SPI Master Waveforms (SSCPHA= 0) SS (output) TCHCH SCK (SSCPOL= 0) (output) TCHCX TCLCH TCLCX TCHCL SCK (SSCPOL= 1) (output) TIVCH TCHIX TIVCL TCLIX MOSI (input) MSB IN BIT 6 LSB IN TCLOX TCLOV TCHOV MISO (output) Note: Port Data MSB OUT TCHOX BIT 6 LSB OUT Port Data 1. SS handled by software using general purpose port pin. Figure 22-16. SPI Master Waveforms (SSCPHA= 1) SS(1) (output) TCHCH SCK (SSCPOL= 0) (output) TCHCX TCLCH TCLCX TCHCL SCK (SSCPOL= 1) (output) TIVCH TCHIX TIVCL TCLIX MOSI (input) MISO (output) Note: 22.4.1 22.4.1.1 MSB IN BIT 6 TCLOV TCLOX TCHOX TCHOV Port Data MSB OUT BIT 6 LSB IN LSB OUT Port Data 1. SS handled by software using general purpose port pin. Two-wire Interface Timings Table 160. TWI Interface AC Timing 194 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C VDD = 2.7 to 3.3 V, TA = -40 to +85°C INPUT Min Max OUTPUT Min Max Start condition hold time 14·TCLCL(4) 4.0 μs(1) TLOW SCL low time 16·TCLCL(4) 4.7 μs(1) THIGH SCL high time 14·TCLCL(4) 4.0 μs(1) TRC SCL rise time 1 μs -(2) TFC SCL fall time 0.3 μs 0.3 μs(3) TSU; DAT1 Data set-up time 250 ns 20·TCLCL(4)- TRD TSU; DAT2 SDA set-up time (before repeated START condition) 250 ns 1 μs(1) TSU; DAT3 SDA set-up time (before STOP condition) 250 ns 8·TCLCL(4) THD; DAT Data hold time 0 ns 8·TCLCL(4) - TFC TSU; STA Repeated START set-up time 14·TCLCL(4) 4.7 μs(1) TSU; STO STOP condition set-up time 14·TCLCL(4) 4.0 μs(1) TBUF Bus free time 14·TCLCL(4) 4.7 μs(1) TRD SDA rise time 1 μs -(2) TFD SDA fall time 0.3 μs 0.3 μs(3) Symbol THD; STA Notes: 22.4.1.2 Parameter 1. At 100 kbit/s. At other bit-rates this value is inversely proportional to the bit-rate of 100 kbit/s. 2. Determined by the external bus-line capacitance and the external bus-line pull-up resistor, this must be < 1 μs. 3. Spikes on the SDA and SCL lines with a duration of less than 3·TCLCL will be filtered out. Maximum capacitance on bus-lines SDA and SCL= 400 pF. 4. TCLCL= TOSC= one oscillator clock period. Waveforms Figure 22-17. Two Wire Waveforms Repeated START condition START or Repeated START condition START condition STOP condition Trd Tsu;STA 0.7 VDD 0.3 VDD SDA (INPUT/OUTPUT) Tsu;STO Tfd Trc Tfc Tbuf Tsu;DAT3 0.7 VDD 0.3 VDD SCL (INPUT/OUTPUT) Thd;STA Tlow Thigh Tsu;DAT1 Thd;DAT Tsu;DAT2 195 4109J–8051–10/06 22.4.2 22.4.2.1 MMC Interface Definition of symbols Table 161. MMC Interface Timing Symbol Definitions Signals 22.4.2.2 Conditions C Clock H High D Data In L Low O Data Out V Valid X No Longer Valid Timings Table 162. MMC Interface AC timings VDD = 2.7 to 3.3 V, TA = -40 to +85°C, CL ≤ 100pF (10 cards) Symbol 22.4.2.3 Parameter Min Max Unit TCHCH Clock Period 50 ns TCHCX Clock High Time 10 ns TCLCX Clock Low Time 10 ns TCLCH Clock Rise Time 10 ns TCHCL Clock Fall Time 10 ns TDVCH Input Data Valid to Clock High 3 ns TCHDX Input Data Hold after Clock High 3 ns TCHOX Output Data Hold after Clock High 5 ns TOVCH Output Data Valid to Clock High 5 ns Waveforms Figure 22-18. MMC Input-Output Waveforms TCHCH TCHCX TCLCX MCLK TCHCL TCHIX TCLCH TIVCH MCMD Input MDAT Input TCHOX TOVCH MCMD Output MDAT Output 196 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 22.4.3 22.4.3.1 Audio Interface Definition of symbols Table 163. Audio Interface Timing Symbol Definitions Signals 22.4.3.2 Conditions C Clock H High O Data Out L Low S Data Select V Valid X No Longer Valid Timings Table 164. Audio Interface AC timings VDD = 2.7 to 3.3 V, TA = -40 to +85°C, CL≤ 30pF Symbol Note: 22.4.3.3 Parameter Min Max Unit 325.5(1) ns TCHCH Clock Period TCHCX Clock High Time 30 ns TCLCX Clock Low Time 30 ns TCLCH Clock Rise Time 10 ns TCHCL Clock Fall Time 10 ns TCLSV Clock Low to Select Valid 10 ns TCLOV Clock Low to Data Valid 10 ns 1. 32-bit format with Fs= 48 KHz. Waveforms Figure 22-19. Audio Interface Waveforms TCHCH TCHCX TCLCX DCLK TCHCL TCLCH TCLSV DSEL Right Left TCLOV DDAT 197 4109J–8051–10/06 22.4.4 22.4.4.1 Analog to Digital Converter Definition of symbols Table 165. Analog to Digital Converter Timing Symbol Definitions Signals 22.4.4.2 Conditions C Clock H High E Enable (ADEN bit) L Low S Start Conversion (ADSST bit) Characteristics Table 166. Analog to Digital Converter AC Characteristics VDD = 2.7 to 3.3 V, TA = -40 to +85°C Symbol Notes: 198 Parameter TCLCL Clock Period TEHSH Start-up Time TSHSL Min Max Unit μs 4 4 μs Conversion Time 11·TCLCL μs DLe Differential nonlinearity error(1)(2) 1 LSB ILe Integral nonlinearity errorss(1)(3) 2 LSB OSe Offset error(1)(4) 4 LSB Ge Gain error(1)(5) 4 LSB 1. AVDD= AVREFP= 3.0 V, AVSS= AVREFN= 0 V. ADC is monotonic with no missing code. 2. The differential non-linearity is the difference between the actual step width and the ideal step width (see Figure 22-21). 3. The integral non-linearity is the peak difference between the center of the actual step and the ideal transfer curve after appropriate adjustment of gain and offset errors (see Figure 22-21). 4. The offset error is the absolute difference between the straight line which fits the actual transfer curve (after removing of gain error), and the straight line which fits the ideal transfer curve (see Figure 22-21). 5. The gain error is the relative difference in percent between the straight line which fits the actual transfer curve (after removing of offset error), and the straight line which fits the ideal transfer curve (see Figure 22-21). AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 22.4.4.3 Waveforms Figure 22-20. Analog to Digital Converter Internal Waveforms CLK TCLCL ADEN Bit TEHSH ADSST Bit TSHSL Figure 22-21. Analog to Digital Converter Characteristics Offset Gain Error Error OSe Ge Code Out 1023 1022 1021 1020 1019 1018 Ideal Transfer curve 7 Example of an actual transfer curve 6 5 Center of a step 4 Integral non-linearity (ILe) 3 Differential non-linearity (DLe) 2 1 0 0 1 LSB (ideal) 1 2 3 4 5 6 7 1018 1019 1020 1021 1022 1023 1024 AVIN (LSB ideal) Offset Error OSe 199 4109J–8051–10/06 22.4.5 22.4.5.1 Flash Memory Definition of symbols Table 167. Flash Memory Timing Symbol Definitions Signals 22.4.5.2 Conditions S ISP L Low R RST V Valid B FBUSY flag X No Longer Valid Timings Table 168. Flash Memory AC Timing VDD = 2.7 to 3.3 V, TA = -40 to +85°C Symbol 22.4.5.3 Parameter Min Typ Max Unit TSVRL Input ISP Valid to RST Edge 50 ns TRLSX Input ISP Hold after RST Edge 50 ns TBHBL FLASH Internal Busy (Programming) Time NFCY Number of Flash Write Cycles TFDR Flash Data Retention Time 10 ms 100K Cycle 10 Years Waveforms Figure 22-22. FLASH Memory - ISP Waveforms RST TSVRL TRLSX (1) ISP Note: 1. ISP must be driven through a pull-down resistor (see Section “In System Programming”, page 185). Figure 22-23. FLASH Memory - Internal Busy Waveforms FBUSY bit 200 TBHBL AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 22.4.6 22.4.6.1 External Clock Drive and Logic Level References Definition of symbols Table 169. External Clock Timing Symbol Definitions Signals C 22.4.6.2 Conditions Clock H High L Low X No Longer Valid Timings External Clock AC Timings VDD = 2.7 to 3.3 V, TA = -40 to +85°C Symbol Parameter Max Unit TCLCL Clock Period 50 ns TCHCX High Time 10 ns TCLCX Low Time 10 ns TCLCH Rise Time 3 ns TCHCL Fall Time 3 ns Cyclic Ratio in X2 mode 40 TCR 22.4.6.3 Min 60 % Waveforms Figure 22-24. External Clock Waveform TCLCH VDD - 0.5 VIH1 TCHCX TCLCX VIL 0.45 V TCHCL TCLCL Figure 22-25. AC Testing Input/Output Waveforms INPUTS VDD - 0.5 0.45 V Note: OUTPUTS 0.7 VDD VIH min 0.3 VDD VIL max 1. During AC testing, all inputs are driven at VDD -0.5 V for a logic 1 and 0.45 V for a logic 0. 2. Timing measurements are made on all outputs at VIH min for a logic 1 and VIL max for a logic 0. Figure 22-26. Float Waveforms VLOAD VLOAD + 0.1 V VLOAD - 0.1 V Timing Reference Points VOH - 0.1 V VOL + 0.1 V 201 4109J–8051–10/06 Note: 202 For timing purposes, a port pin is no longer floating when a 100 mV change from load voltage occurs and begins to float when a 100 mV change from the loading VOH/VOL level occurs with IOL/IOH= ±20 mA. AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 24. Ordering Information Part Number Memory Size Supply Voltage Temperature Range Max Frequency Package(2) Packing Product Marking AT89C51SND1C-ROTIL 64K Flash 3V Industrial 40 MHz TQFP80 Tray 89C51SND1C-IL AT89C51SND1C-7HTIL 64K Flash 3V Industrial 40 MHz BGA81 Tray 89C51SND1C-IL AT89C51SND1C-DDV 64K Flash 3V Industrial 40 MHz Dice Tray - AT83SND1Cxxx(1)-ROTIL 64K ROM 3V Industrial 40 MHz TQFP80 Tray 89C51SND1C-IL AT83SND1Cxxx(1)-7HTIL 64K ROM 3V Industrial 40 MHz BGA81 Tray 89C51SND1C-IL AT83SND1Cxxx-DDV 64K ROM 3V Industrial 40 MHz Dice Tray - AT80C51SND1C-ROTIL ROMless 3V Industrial 40 MHz TQFP80 Tray 89C51SND1C-IL AT80C51SND1C-7HTIL ROMless 3V Industrial 40 MHz BGA81 Tray 89C51SND1C-IL AT80C51SND1C-DDV ROMless 3V Industrial 40 MHz Dice Tray - AT89C51SND1C-ROTUL 64K Flash 3V Industrial & Green 40 MHz TQFP80 Tray 89C51SND1C-IL AT89C51SND1C-7HTJL 64K Flash 3V Industrial 40 MHz BGA81 Tray 89C51SND1C-IL 40 MHz TQFP80 Tray 89C51SND1C-IL AT83SND1Cxxx(1)-ROTUL 64K ROM 3V Industrial & Green AT83SND1Cxxx(1)-7HTJL 64K ROM 3V Industrial & Green 40 MHz BGA81 Tray 89C51SND1C-IL AT80C51SND1C-ROTUL ROMless 3V Industrial & Green 40 MHz TQFP80 Tray 89C51SND1C-IL AT80C51SND1C-7HTJL ROMless 3V Industrial & Green 40 MHz BGA81 Tray 89C51SND1C-IL Notes: 1. Refers to ROM code. 2. PLCC84 package only available for development board. 203 4109J–8051–10/06 25. Package Information 25.1 204 TQFP80 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 25.2 BGA81 205 4109J–8051–10/06 25.3 206 PLCC84 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 26. Datasheet Revision History for AT8xC51SND1C 26.1 Changes from 4109D-10/02 to 4109E-06/03 1. Additional information on AT83SND1C product. 2. Added BGA81 package. 3. Updated AC/DC characteristics for AT89C51SND1C product. 4. Changed the endurance of Flash to 100, 000 Write/Erase cycles. 5. Added note on Flash retention formula for VIH1, in Section "DC Characteristics", page 180. 26.2 Changes from 4109E-06/03 to 4109F-01/04 1. Added AT80C51SND1C ROMless product. 2. Updated DC characteristics for AT83SND1C product. 26.3 Changes from 4109F-01/04 to 4109G-07/04 1. UART bootloader now flagged as option in Features section. 2. Add USB connection schematic in USB section. 3. Add USB termination characteristics in DC Characteristics section. 4. Page access mode clarification in Data Memory section. 26.4 Changes from 4109G-07/04 to 4109H-01/05 1. Clarify EA pin not present on packages but on dice. 2. Interrupt priority number clarification to match number defined by development tools 26.5 Changes from 4109H-01/05 to 4109I-01/06 1. Added green product ordering information. 26.6 Changes from 4109I-01/06 to 4109J-10/06 1. Added pull-up in USB connection figure. Section 22.2 on page 180. 207 4109J–8051–10/06 27. Table of Contents 1 Description ............................................................................................... 2 2 Typical Applications ................................................................................ 2 3 Block Diagram .......................................................................................... 2 4 Pin Description ......................................................................................... 3 4.1 Pinouts ....................................................................................................................3 4.2 Signals .....................................................................................................................5 4.3 Internal Pin Structure .............................................................................................11 5 Clock Controller ..................................................................................... 12 5.1 Oscillator ...............................................................................................................12 5.2 X2 Feature .............................................................................................................12 5.3 PLL ........................................................................................................................13 5.4 Registers ...............................................................................................................15 6 Data Memory .......................................................................................... 25 6.1 Internal Space .......................................................................................................25 6.2 External Space ......................................................................................................26 6.3 Dual Data Pointer ..................................................................................................28 6.4 Registers ...............................................................................................................30 7 Special Function Registers ................................................................... 32 8 Interrupt System .................................................................................... 38 8.1 Interrupt System Priorities .....................................................................................38 8.2 External Interrupts .................................................................................................41 8.3 Registers ...............................................................................................................42 9 Power Management ............................................................................... 47 9.1 Reset .....................................................................................................................47 9.2 Reset Recommendation to Prevent Flash Corruption ...........................................48 9.3 Idle Mode ...............................................................................................................49 9.4 Power-down Mode ................................................................................................49 9.5 Registers ...............................................................................................................51 10 Timers/Counters .................................................................................... 52 10.1 Timer/Counter Operations ...................................................................................52 10.2 Timer Clock Controller .........................................................................................52 208 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 10.3 Timer 0 ................................................................................................................53 10.4 Timer 1 ................................................................................................................55 10.5 Interrupt ............................................................................................................... 56 10.6 Registers .............................................................................................................56 11 Watchdog Timer ..................................................................................... 60 11.1 Description ..........................................................................................................60 11.2 Watchdog Clock Controller ..................................................................................60 11.3 Watchdog Operation ...........................................................................................61 11.4 Registers .............................................................................................................62 12 MP3 Decoder .......................................................................................... 63 12.1 Decoder ...............................................................................................................63 12.2 Audio Controls .....................................................................................................64 12.3 Decoding Errors ..................................................................................................65 12.4 Frame Information ...............................................................................................66 12.5 Ancillary Data ......................................................................................................66 12.6 Interrupt ............................................................................................................... 66 12.7 Registers .............................................................................................................68 13 Audio Output Interface .......................................................................... 73 13.1 Description ..........................................................................................................73 13.2 Clock Generator ..................................................................................................73 13.3 Data Converter ....................................................................................................74 13.4 Audio Buffer .........................................................................................................75 13.5 MP3 Buffer ..........................................................................................................76 13.6 Interrupt Request .................................................................................................76 13.7 MP3 Song Playing ...............................................................................................76 13.8 Voice or Sound Playing .......................................................................................77 13.9 Registers .............................................................................................................77 14 Universal Serial Bus .............................................................................. 80 14.1 Description ..........................................................................................................80 14.2 Configuration .......................................................................................................83 14.3 Read/Write Data FIFO .........................................................................................85 14.4 Bulk/Interrupt Transactions .................................................................................86 14.5 Control Transactions ...........................................................................................90 14.6 Isochronous Transactions ...................................................................................90 14.7 Miscellaneous ......................................................................................................92 209 4109J–8051–10/06 14.8 Suspend/Resume Management ..........................................................................93 14.9 USB Interrupt System ..........................................................................................95 14.10 Registers ...........................................................................................................97 15 MultiMedia Card Controller ................................................................. 108 15.1 Card Concept ....................................................................................................108 15.2 Bus Concept ......................................................................................................108 15.3 Description ........................................................................................................113 15.4 Clock Generator ................................................................................................114 15.5 Command Line Controller .................................................................................114 15.6 Data Line Controller ..........................................................................................116 15.7 Interrupt .............................................................................................................122 15.8 Registers ...........................................................................................................123 16 IDE/ATAPI Interface ............................................................................. 130 16.1 Description ........................................................................................................130 16.2 Registers ...........................................................................................................132 17 Serial I/O Port ....................................................................................... 133 17.1 Mode Selection ..................................................................................................133 17.2 Baud Rate Generator ........................................................................................133 17.3 Synchronous Mode (Mode 0) ............................................................................134 17.4 Asynchronous Modes (Modes 1, 2 and 3) .........................................................136 17.5 Multiprocessor Communication (Modes 2 and 3) ..............................................139 17.6 Automatic Address Recognition ........................................................................140 17.7 Interrupt .............................................................................................................141 17.8 Registers ...........................................................................................................142 18 Synchronous Peripheral Interface ..................................................... 146 18.1 Description ........................................................................................................147 18.2 Interrupt .............................................................................................................150 18.3 Configuration .....................................................................................................150 18.4 Registers ...........................................................................................................155 19 Two-wire Interface (TWI) Controller ................................................... 157 19.1 Description ........................................................................................................157 19.2 Registers ...........................................................................................................171 20 Analog to Digital Converter ................................................................ 173 20.1 Description ........................................................................................................173 210 AT8xC51SND1C 4109J–8051–10/06 AT8xC51SND1C 20.2 Registers ...........................................................................................................176 21 Keyboard Interface .............................................................................. 178 21.1 Description ........................................................................................................178 21.2 Registers ...........................................................................................................178 22 Electrical Characteristics .................................................................... 180 22.1 Absolute Maximum Rating ................................................................................180 22.2 DC Characteristics ............................................................................................180 23 AC Characteristics ............................................................................... 186 23.1 External Program Bus Cycles ...........................................................................186 23.2 SPI Interface ......................................................................................................191 24 Ordering Information ........................................................................... 203 25 Package Information ............................................................................ 204 25.1 TQFP80 .............................................................................................................204 25.2 BGA81 ...............................................................................................................205 25.3 PLCC84 .............................................................................................................206 26 Datasheet Revision History for AT8xC51SND1C .............................. 207 26.1 Changes from 4109D-10/02 to 4109E-06/03 ....................................................207 26.2 Changes from 4109E-06/03 to 4109F-01/04 .....................................................207 26.3 Changes from 4109F-01/04 to 4109G-07/04 ....................................................207 26.4 Changes from 4109G-07/04 to 4109H-01/05 ....................................................207 26.5 Changes from 4109H-01/05 to 4109I-01/06 ......................................................207 27 Table of Contents ................................................................................. 208 211 4109J–8051–10/06 Atmel Corporation 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600 Regional Headquarters Europe Atmel Sarl Route des Arsenaux 41 Case Postale 80 CH-1705 Fribourg Switzerland Tel: (41) 26-426-5555 Fax: (41) 26-426-5500 Asia Room 1219 Chinachem Golden Plaza 77 Mody Road Tsimshatsui East Kowloon Hong Kong Tel: (852) 2721-9778 Fax: (852) 2722-1369 Japan 9F, Tonetsu Shinkawa Bldg. 1-24-8 Shinkawa Chuo-ku, Tokyo 104-0033 Japan Tel: (81) 3-3523-3551 Fax: (81) 3-3523-7581 Atmel Operations Memory 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 RF/Automotive Theresienstrasse 2 Postfach 3535 74025 Heilbronn, Germany Tel: (49) 71-31-67-0 Fax: (49) 71-31-67-2340 Microcontrollers 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 La Chantrerie BP 70602 44306 Nantes Cedex 3, France 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