T89C51AC2 8-bit MCU with 32K bytes Flash, 10 bits A/D and EEPROM 1. Description The T89C51AC2 is a high performance CMOS FLASH version of the 80C51 CMOS single chip 8-bit microcontrollers. It contains a 32Kbytes Flash memory block for program and data. The fully static design of the T89C51AC2 allows to reduce system power consumption by bringing the clock frequency down to any value, even DC, without loss of data. The 16K bytes or 32K bytes FLASH memory can be programmed either in parallel mode or in serial mode with the ISP capability or with software. The programming voltage is internally generated from the standard VCC pin. The T89C51AC2 has 2 software-selectable modes of reduced activity and 8 bit clock prescaler for further reduction in power consumption. In the Idle mode the CPU is frozen while the peripherals and the interrupt system are still operating. In the power-down mode the RAM is saved and all other functions are inoperative. The T89C51AC2 retains all features of the 80C52 with 256 bytes of internal RAM, a 7-source 4-level interrupt controller and three timer/counters. In addition, the T89C51AC2 has a 10 bits A/D converter, a 2Kbytes Boot Flash Memory, 2 Kbytes EEPROM for data, a Programmable Counter Array, an XRAM of 1024 byte, a Hardware Watchdog Timer and a more versatile serial channel that facilitates multiprocessor communication (EUART). The added features of the T89C51AC2 make it more powerful for applications that need A/D conversion, pulse width modulation, high speed I/O and counting capabilities such as industrial control, consumer goods, alarms, motor control, ... While remaining fully compatible with the 80C51 it offers a superset of this standard microcontroller. In X2 mode a maximum external clock rate of 20 MHz reaches a 300 ns cycle time. 2. Features • 80C51 core architecture: • • • • • • • • • 256 bytes of on-chip RAM 1Kbytes of on-chip XRAM 32 Kbytes of on-chip Flash memory 2 Kbytes of on-chip Flash for Bootloader 2 Kbytes of on-chip EEPROM 14-source 4-level interrupt Three 16-bit timer/counter Full duplex UART compatible 80C51 maximum crystal frequency 40 MHz. In X2 mode, 20 MHz (CPU core, 40 MHz) • Five ports: 32 + 2 digital I/O lines • Five channel 16-bit PCA with: - PWM (8-bit) - High-speed output - Timer and edge capture • Double Data Pointer • 21 bit watchdog timer (including 7 programmable bits) • A 10-bit resolution analog to digital converter (ADC) with 8 multiplexed inputs • 20 microsecond conversion time • Two conversion modes On-chip emulation Logic (enhanced Hook system) • • Power saving modes: • Idle mode • Power down mode Power supply: 5V +/- 10% (or 3V** +/- 10%) • • Temperature range: Industrial (-40 to +85C) • Packages: TQFP44, PLCC44 Draft.A- March 30, 2001 1 Preview - Confidential T89C51AC2 T2 T2EX PCA ECI Vss Vcc TxD RxD 3. Block Diagram XTAL1 RAM 256x8 UART XTAL2 ALE C51 CORE PSEN Flash 32kx 8 ERAM Boot EE 1kx8 loader PROM 2kx8 2kx8 PCA Timer2 IB-bus CPU EA Timer 0 Timer 1 RD INT Ctrl Parallel I/O Ports & Ext. Bus Watch Dog 10 bit ADC P4(2) P3 P2 P1(1) INT1 INT0 T1 T0 RESET WR P0 Port 0 Port 1 Port 2 Port 3 Port 4 Emul Unit (1): 8 analog Inputs / 8 Digital I/O (2): 2-Bit I/O Port 2 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 6 5 4 3 2 1 44 43 42 41 40 P1.3 / AN3 / CEX0 P1.2 / AN2 / ECI P1.1 / AN1 / T2EX P1.0 / AN 0 / T2 VAREF VAGND RESET VSS VCC XTAL1 XTAL2 4. Pin Configuration 7 8 9 10 11 12 13 14 15 16 17 39 38 37 36 35 34 33 32 31 30 29 PLCC44 ALE PSEN P0.7 / AD7 P0.6 / AD6 P0.5 / AD5 P0.4 / AD4 P0.3 / AD3 P0.2 / AD2 P0.1 / AD1 P0.0 / AD0 P2.0 / A8 P1.3 / AN3 / CEX0 P1.2 / AN2 / ECI P1.1 / AN1 / T2EX P1.0 / AN 0 / T2 VAREF VAGND RESET VSS VCC XTAL1 XTAL2 P3.6 / WR P3.7 / RD P4.0 P4.1 P2.7 / A15 P2.6 / A14 P2.5 / A13 P2.4 / A12 P2.3 / A11 P2.2 / A10 P2.1 / A9 18 19 20 21 22 23 24 25 26 27 28 P1.4 / AN4 / CEX1 P1.5 / AN5 / CEX2 P1.6 / AN6 / CEX3 P1.7 / AN7 / CEX4 EA P3.0 / RxD P3.1 / TxD P3.2 / INT0 P3.3 / INT1 P3.4 / T0 P3.5 / T1 44 43 42 41 40 39 38 37 36 35 34 P1.4 / AN4 / CEX1 P1.5 / AN5 / CEX2 P1.6 / AN6 / CEX3 P1.7 / AN7 / CEX4 EA P3.0 / RxD P3.1 / TxD P3.2 / INT0 P3.3 / INT1 P3.4 / T0 P3.5 / T1 2 33 32 3 4 30 1 5 6 7 8 31 TQFP44 29 28 27 9 26 25 10 24 23 11 ALE PSEN P0.7 / AD7 P0.6 / AD6 P0.5 / AD5 P0.4 /AD4 P0.3 /AD3 P0.2 /AD2 P0.1 /AD1 P0.0 /AD0 P2.0 / A8 P3.6 / WR P3.7 / RD P4.0 P4.1 P2.7 / A15 P2.6 / A14 P2.5 / A13 P2.4 / A12 P2.3 / A11 P2.2 / A10 P2.1 / A9 1213 14 15 16 17 18 19 20 2122 Draft.A - March 30, 2001 3 Preview - Confidential T89C51AC2 Table 1. Pin Description Pin Name Type VSS GND VCC Description Circuit ground potential. Supply voltage during normal, idle, and power-down operation. VAREF Reference Voltage for ADC VAGND Reference Ground for ADC P0.0:7 I/O Port 0: is an 8-bit open drain bi-directional I/O port. Port 0 pins that have 1’s written to them float, and in this state can be used as high-impedance inputs. Port 0 is also the multiplexed low-order address and data bus during accesses to external Program and Data Memory. In this application it uses strong internal pullups when emitting 1’s. Port 0 also outputs the code bytes during program validation. External pull-ups are required during program verification. In the T89C51AC2 Port 0 can sink or source 5mA. It can drive CMOS inputs without external pull-ups. Port 1: is an 8-bit bi-directional I/O port with internal pull-ups. Port 1 pins can be used for digital input/output or as analog inputs for the Analog Digital Converter (ADC). Port 1 pins that have 1’s written to them are pulled high by the internal pull-up transistors and can be used as inputs in this state. As inputs, Port 1 pins that are being pulled low externally will be the source of current (IIL, on the datasheet) because of the internal pull-ups. Port 1 pins are assigned to be used as analog inputs via the ADCCF register. As a secondary digital function, port 1 contains the Timer 2 external trigger and clock input; the PCA external clock input and the PCA module I/O. P1.0:7 I/O P1.0 / AN0 / T2 Analog input channel 0, External clock input for Timer/counter2. P1.1 / AN1 / T2EX Analog input channel 1, Trigger input for Timer/counter2. P1.2 / AN2 / ECI Analog input channel 2, PCA external clock input. P1.3 / AN3 / CEX0 Analog input channel 3, PCA module 0 Entry of input/PWM output. P1.4 / AN4 / CEX1 Analog input channel 4, PCA module 1 Entry of input/PWM output. P1.5 / AN5 / CEX2 Analog input channel 5, PCA module 2 Entry of input/PWM output. P1.6 / AN6 / CEX3 Analog input channel 6, PCA module 3 Entry of input/PWM output. P1.7 / AN7 / CEX4 Analog input channel 7, PCA module 4 Entry ot input/PWM output. Port 1 receives the low-order address byte during EPROM programming and program verification. In the T89C51AC2 Port 1 can sink or source 5mA. It can drive CMOS inputs without external pull-ups. P2.0:7 I/O Port 2: Is an 8-bit bi-directional I/O port with internal pull-ups. Port 2 pins that have 1’s written to them are pulled high by the internal pull-ups and can be used as inputs in this state. As inputs, Port 2 pins that are being pulled low externally will be a source of current (IIL, on the datasheet) because of the internal pull-ups. Port 2 emits the high-order address byte during accesses to the external Program Memory and during accesses to external Data Memory that uses 16-bit addresses (MOVX @DPTR). In this application, it uses strong internal pullups when emitting 1’s. During accesses to external Data Memory that use 8 bit addresses (MOVX @Ri), Port 2 transmits the contents of the P2 special function register. It also receives high-order addresses and control signals during program validation. In the T89C51AC2 Port 2 can sink or source 5mA. It can drive CMOS inputs without external pull-ups. 4 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 Pin Name Type Description Port 3: Is an 8-bit bi-directional I/O port with internal pull-ups. Port 3 pins that have 1’s written to them are pulled high by the internal pull-up transistors and can be used as inputs in this state. As inputs, Port 3 pins that are being pulled low externally will be a source of current (IIL, on the datasheet) because of the internal pull-ups. The output latch corresponding to a secondary function must be programmed to one for that function to operate (except for TxD and WR). The secondary functions are assigned to the pins of port 3 as follows: P3.0:7 P4.0:1 I/O I/O P3.0 / RxD: Receiver data input (asynchronous) or data input/output (synchronous) of the serial interface P3.1 / TxD: Transmitter data output (asynchronous) or clock output (synchronous) of the serial interface P3.2 / INT0: External interrupt 0 input / timer 0 gate control input P3.3 / INT1: External interrupt 1 input / timer 1 gate control input P3.4 / T0: Timer 0 counter input P3.5 / T1: Timer 1 counter input P3.6 / WR: External Data Memory write strobe; latches the data byte from port 0 into the external data memory P3.7 / RD: External Data Memory read strobe; Enables the external data memory. In the T89C51AC2 Port 3 can sink or source 5mA. It can drive CMOS inputs without external pull-ups. Port 4: Is an 2-bit bi-directional I/O port with internal pull-ups. Port 4 pins that have 1’s written to them are pulled high by the internal pull-ups and can be used as inputs in this state. As inputs, Port 4 pins that are being pulled low externally will be a source of current (IIL, on the datasheet) because of the internal pullup transistor. In the T89C51AC2 Port 3 can sink or source 5mA. It can drive CMOS inputs without external pull-ups. RESET ALE PSEN I/O Reset: A high level on this pin during two machine cycles while the oscillator is running resets the device. An internal pull-down resistor to VSS permits power-on reset using only an external capacitor to VCC. O ALE: An Address Latch Enable output for latching the low byte of the address during accesses to the external memory. The ALE is activated every 1/6 oscillator periods (1/3 in X2 mode) except during an external data memory access. When instructions are executed from an internal FLASH (EA = 1), ALE generation can be disabled by the software. O PSEN: The Program Store Enable output is a control signal that enables the external program memory of the bus during external fetch operations. It is activated twice each machine cycle during fetches from the external program memory. (However, when executing outside of the external program memory two activations of PSEN are skipped during each access to the external Data memory). The PSEN is not activated during fetches from the internal data memory. EA: EA I When External Access is held at the high level, instructions are fetched from the internal FLASH when the program counter is less then 8000H. When held at the low level, CANARY fetches all instructions from the external program memory. XTAL1 I XTAL1: Input of the inverting oscillator amplifier and input of the internal clock generator circuits. To drive the device from an external clock source, XTAL1 should be driven, while XTAL2 is left unconnected. To operate above a frequency of 16 MHz, a duty cycle of 50% should be maintained. XTAL2 O XTAL2: Output from the inverting oscillator amplifier. Draft.A - March 30, 2001 5 Preview - Confidential T89C51AC2 4.1. I/O Configurations Each Port SFR operates via type-D latches, as illustrated in Figure 1 for Ports 3 and 4. A CPU "write to latch" signal initiates transfer of internal bus data into the type-D latch. A CPU "read latch" signal transfers the latched Q uotput onto the internal bus. Similarly, a "read pin" signal transfers the logical level of the Port pin. Some Port data instructions activate the "read latch" signal while others activate the "read pin" signal. Latch instructions are referred to as Read-Modify-Write instructions. Each I/O line may be independently programmed as input or output. 4.2. Port 1, Port 3 and Port 4 Figure 1 shows the structure of Ports 1 and 3, which have internal pull-ups. An external source can pull the pin low. Each Port pin can be configured either forgeneral-purpose I/O or for its alternate input output function. To use a pin for general-purpose output, set or clear the corresponding bit in the Px register (x=1,3 or 4). To use a pin for general purpose input, set the bit in the Px register. This turns off the output FET drive. To configure a pin for its alternate function, set the bit in the Px register. When the latch is set, the "alternate output function" signal controls the output level (see Figure 1). The operation of Ports 1, 3 and 4 is discussed further in "quasi-Bidirectional Port Operation" paragraph. VCC ALTERNATE OUTPUT FUNCTION READ LATCH INTERNAL BUS WRITE TO LATCH READ PIN INTERNAL PULL-UP (1) P1.x P3.x P4.x D P1.X Q P3.X P4.X LATCH CL ALTERNATE INPUT FUNCTION NOTE: 1. The internal pull-up can be disabled on P1 when analog function is selected. Figure 1. Port 1, Port 3 and Port 4 Structure 4.3. Port 0 and Port2 Ports 0 and 2 are used for general-purpose I/O or as the external address/data bus. Port 0, shown in Figure 2, differs from the other Ports in not having internal pull-ups. Figure 3 shows the structure of Port 2. An external source can pull a Port 2 pin low. To use a pin for general-purpose output, set or clear the corresponding bit in the Px register (x=0 or 2). To use a pin for general purpose input, set the bit in the Px register to turn off the output driver FET. 6 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 ADDRESS LOW/ CONTROL DATA VDD (2) READ LATCH P0.x (1) 1 INTERNAL BUS WRITE TO LATCH D Q P0.X LATCH 0 READ PIN NOTE: 1. Port 0 is precluded from use as general purpose I/O Ports when used as address/data bus drivers. 2. Port 0 internal strong pull-ups assist the logic-one output for memory bus cycles only. Except for these bus cycles, the pull-up FET is off, Port 0 outputs are open-drain. Figure 2. Port 0 Structure ADDRESS HIGH/ CONTROL DATA VDD INTERNAL PULL-UP (2) READ LATCH P2.x (1) 1 INTERNAL BUS WRITE TO LATCH D Q P2.X LATCH 0 READ PIN NOTE: 1. Port 2 is precluded from use as general purpose I/O Ports when as address/data bus drivers. 2. Port 2 internal strong pull-ups FET (P1 in FiGURE) assist the logic-one output for memory bus cyle. Figure 3. Port 2 Structure When Port 0 and Port 2 are used for an external memory cycle, an internal control signal switches the outputdriver input from the latch output to the internal address/data line. Draft.A - March 30, 2001 7 Preview - Confidential T89C51AC2 4.4. Read-Modify-Write Instructions Some instructions read the latch data rather than the pin data. The latch based instructions read the data, modify the data and then rewrite the latch. These are called "Read-Modifiy-Write" instructions. Below is a complete list of these special instructions (see Table 2). When the destination operand is a Port or a Port bit, these instructions read the latch rather than the pin: Table 2. Read-Modify-Write Instructions Instruction Description Example ANL logical AND ANL P1, A ORL logical OR ORL P2, A XRL logical EX-OR XRL P3, A JBC jump if bit = 1 and clear bit JBC P1.1, LABEL CPL complement bit CPL P3.0 INC increment INC P2 DEC decrement DEC P2 DJNZ decrement and jump if not zero DJNZ P3, LABEL MOV Px.y, C move carry bit to bit y of Port x MOV P1.5, C CLR Px.y clear bit y of Port x CLR P2.4 SET Px.y set bit y of Port x SET P3.3 It is not obvious the last three instructions in this list are Read-Modify-Write instructions. These instructions read the port (all 8 bits), modify the specifically addressed bit and write the new byte back to the latch. These ReadModify-Write instructions are directed to the latch rather than the pin in order to avoid possible misinterpretation of voltage (and therefore, logic)levels at the pin. For example, a Port bit used to drive the base of an external bipolar transistor can not rise above the transistor’s base-emitter junction voltage (a value lower than VIL). With a logic one written to the bit, attemps by the CPU to read the Port at the pin are misinterpreted as logic zero. A read of the latch rather than the pins returns the correct logic-one value. 4.5. Quasi-Bidirectional Port Operation Port 1, Port 2, Port 3 and Port 4 have fixed internal pull-ups and are referred to as "quasi-bidirectional" Ports. When configured as an input, the pin impedance appears as logic one and sources current in response to an external logic zero condition. Port 0 is a "true bidirectional" pin. The pins float when configured as input. Resets write logic one to all Port latches. If logical zero is subsequently written to a Port latch, it can be returned to input condions by a logical one written to the latch. NOTE: Port latch values change near the end of Read-Modify-Write insruction cycles. Output buffers (and therefore the pin state) update early in the instruction after Read-Modify-Write instruction cycle. Logical zero-to-one transitions in Port 1, Port 2, Port 3 and Port 4 use an additional pull-up (p1) to aid this logic transition (see Figure 4.). This increases switch speed. This extra pull-up sources 100 times normal internal circuit current during 2 oscillator clock periods. The internal pull-ups are field-effect transistors rather than linear resistors. Pull-ups consist of three p-channel FET (pFET) devices. A pFET is on when the gate senses logical zero and off when the gate senses logical one. pFET #1 is turned on for two oscillator periods immediately after a zero-to-one transition in the Port latch. A logical one at the Port pin turns on pFET #3 (a weak pull-up) through the inverter. This inverter and pFET pair form a latch to drive logical one. pFET #2 is a very weak pull-up switched on whenever the associated nFET is switched off. This is traditional CMOS switch convention. Current strengths are 1/10 that of pFET #3. 8 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 2 Osc. PERIODS VCC VCC VCC p1(1) p2 p3 P1.x P2.x P3.x P4.x OUTPUT DATA n INPUT DATA READ PIN NOTE: 1. Port 2 p1 assists the logic-one output for memory bus cycles. Figure 4. Internal Pull-Up Configurations Draft.A - March 30, 2001 9 Preview - Confidential T89C51AC2 5. SFR Mapping The Special Function Registers (SFRs) of the T89C51AC2 fall into the following categories: Table 3. C51 Core SFRs Mnemonic Add Name 7 ACC E0h Accumulator B F0h PSW D0h Program Status Word SP 81h Stack Pointer LSB of SPX DPL 82h Data Pointer Low byte LSB of DPTR DPH 83h Data Pointer High byte MSB of DPTR 6 5 4 3 2 1 0 4 3 2 1 0 B Register Table 4. I/O Port SFRs Mnemonic Add Name P0 80h Port 0 P1 90h Port 1 P2 A0h Port 2 P3 B0h Port 3 P4 C0h Port 4 (x2) 7 6 5 Table 5. Timers SFRs Mnemonic Add Name TH0 8Ch Timer/Counter 0 High byte TL0 8Ah Timer/Counter 0 Low byte TH1 8Dh Timer/Counter 1 High byte 7 6 5 4 3 2 1 0 TF0 TR0 IE1 IT1 IE0 IT0 TL1 8Bh Timer/Counter 1 Low byte TH2 CDh Timer/Counter 2 High byte TL2 CCh Timer/Counter 2 Low byte TCON 88h Timer/Counter 0 and 1 control TF1 TR1 TMOD 89h Timer/Counter 0 and 1 Modes GATE1 C/T1# M11 M01 GATE0 C/T0# M10 M00 T2CON C8h Timer/Counter 2 control TF2 EXF2 RCLK TCLK EXEN2 TR2 C/T2# CP/RL2# T2MOD C9h Timer/Counter 2 Mode - - - - - - T2OE DCEN RCAP2H Timer/Counter 2 Reload/Capture CBh High byte RCAP2L CAh WDTRST A6h WatchDog Timer Reset WDTPRG A7h WatchDog Timer Program - - - - - S2 S1 S0 Timer/Counter 2 Reload/Capture Low byte Table 6. Serial I/O Port SFRs Mnemonic Add Name SCON 98h Serial Control SBUF 99h Serial Data Buffer SADEN B9h Slave Address Mask 7 6 5 4 3 2 1 0 FE/SM0 SM1 SM2 REN TB8 RB8 TI RI 10 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 Mnemonic Add SADDR Name 7 6 5 4 3 2 1 0 5 4 3 2 1 0 A9h Slave Address Table 7. PCA SFRs Mnemonic Add Name 7 CCON D8h PCA Timer/Counter Control CMOD D9h PCA Timer/Counter Mode CL E9h PCA Timer/Counter Low byte CH F9h PCA Timer/Counter High byte CCAPM0 CCAPM1 CCAPM2 CCAPM3 CCAPM4 DAh DBh DCh DDh DEh PCA PCA PCA PCA PCA CCAP0H CCAP1H CCAP2H CCAP3H CCAP4H FAh FBh FCh FDh FEh CCAP0L CCAP1L CCAP2L CCAP3L CCAP4L EAh EBh ECh EDh EEh 6 CF CR - CCF4 CCF3 CCF2 CCF1 CCF0 CIDL WDTE - - - CPS1 CPS0 ECF - ECOM0 ECOM1 ECOM2 ECOM3 ECOM4 CAPP0 CAPP1 CAPP2 CAPP3 CAPP4 CAP0 CAP1 CAP2 CAP3 CAP4 MAT0 MAT1 MAT2 MAT3 MAT4 TOG0 TOG1 TOG2 TOG3 TOG4 PWM0 PWM1 PWM2 PWM3 PWM4 ECCF0 ECCF1 ECCF2 ECCF3 ECCF4 PCA Compare Capture Module 0 H PCA Compare Capture Module 1 H PCA Compare Capture Module 2 H PCA Compare Capture Module 3 H PCA Compare Capture Module 4 H CCAP0H7 CCAP1H7 CCAP2H7 CCAP3H7 CCAP4H7 CCAP0H6 CCAP1H6 CCAP2H6 CCAP3H6 CCAP4H6 CCAP0H5 CCAP1H5 CCAP2H5 CCAP3H5 CCAP4H5 CCAP0H4 CCAP1H4 CCAP2H4 CCAP3H4 CCAP4H4 CCAP0H3 CCAP1H3 CCAP2H3 CCAP3H3 CCAP4H3 CCAP0H2 CCAP1H2 CCAP2H2 CCAP3H2 CCAP4H2 CCAP0H1 CCAP1H1 CCAP2H1 CCAP3H1 CCAP4H1 CCAP0H0 CCAP1H0 CCAP2H0 CCAP3H0 CCAP4H0 PCA Compare Capture Module 0 L PCA Compare Capture Module 1 L PCA Compare Capture Module 2 L PCA Compare Capture Module 3 L PCA Compare Capture Module 4 L CCAP0L7 CCAP1L7 CCAP2L7 CCAP3L7 CCAP4L7 CCAP0L6 CCAP1L6 CCAP2L6 CCAP3L6 CCAP4L6 CCAP0L5 CCAP1L5 CCAP2L5 CCAP3L5 CCAP4L5 CCAP0L4 CCAP1L4 CCAP2L4 CCAP3L4 CCAP4L4 CCAP0L3 CCAP1L3 CCAP2L3 CCAP3L3 CCAP4L3 CCAP0L2 CCAP1L2 CCAP2L2 CCAP3L2 CCAP4L2 CCAP0L1 CCAP1L1 CCAP2L1 CCAP3L1 CCAP4L1 CCAP0L0 CCAP1L0 CCAP2L0 CCAP3L0 CCAP4L0 1 0 Timer/Counter Timer/Counter Timer/Counter Timer/Counter Timer/Counter Mode Mode Mode Mode Mode 0 1 2 3 4 Table 8. Interrupt SFRs Mnemonic Add Name 7 6 5 4 3 2 IEN0 A8h Interrupt Enable Control 0 EA AC ET2 ES ET1 EX1 ET0 EX0 IEN1 E8h Interrupt Enable Control 1 - - - - - - EADC - IPL0 B8h Interrupt Priority Control Low 0 - PPC PT2 PS PT1 PX1 PT0 PX0 IPH0 B7h Interrupt Priority Control High 0 - PPCH PT2H PSH PT1H PX1H PT0H PX0H IPL1 F8h Interrupt Priority Control Low 1 - - - - - - PADCL - IPH1 F7h Interrupt Priority Control High1 - - - - - - PADCH - Table 9. ADC SFRs Mnemonic Add Name ADCON F3h ADC Control ADCF F6h ADC Configuration 7 6 5 4 3 2 1 0 - PSIDLE ADEN ADEOC ADSST SCH2 SCH1 SCH0 CH7 CH6 CH5 CH4 CH3 CH2 CH1 CH0 ADCLK F2h ADC Clock - - - PRS4 PRS3 PRS2 PRS1 PRS0 ADDH F5h ADC Data High byte ADAT9 ADAT8 ADAT7 ADAT6 ADAT5 ADAT4 ADAT3 ADAT2 ADDL F4h ADC Data Low byte - - - - - - ADAT1 ADAT0 Draft.A - March 30, 2001 11 Preview - Confidential T89C51AC2 Table 10. Other SFRs Mnemonic Add PCON Name 87hh Power Control 7 6 5 4 3 2 1 0 SMOD1 SMOD0 - POF GF1 GF0 PD IDL AUXR 8Eh Auxiliary Register 0 - M(1) M0 - XRS1 XRS2 EXTRAM A0 AUXR1 A2h Auxiliary Register 1 - - ENBOOT - GF3 - - DPS CKCON 8Fh FCON D1h FLASH Control Clock Control EECON D2h EEPROM Contol - WDX2 PCAX2 SIX2 T2X2 T1X2 T0X2 X2 FPL3 FPL2 FPL1 FPL0 FPS FMOD1 FMOD0 FBUSY EEPL3 EEPL2 EEPL1 EEPL0 - - EEE EEBUSY 12 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 Table 11. SFR’s mapping 0/8(1) 1/9 2/A 3/B 4/C 5/D 6/E F8h IPL1 xxxx x000 CH 0000 0000 CCAP0H 0000 0000 CCAP1H 0000 0000 CCAP2H 0000 0000 CCAP3H 0000 0000 CCAP4H 0000 0000 F0h B 0000 0000 ADCLK xx00 0000 ADCON x000 0000 ADDL 0000 0000 ADDH 0000 0000 ADCF 0000 0000 E8h IEN1 xxxx x000 CCAP0L 0000 0000 CCAP1L 0000 0000 CCAP2L 0000 0000 CCAP3L 0000 0000 CCAP4L 0000 0000 E0h ACC 0000 0000 D8h CCON 00xx xx00 CMOD 00xx x000 CCAPM0 x000 0000 D0h PSW 0000 0000 FCON 0000 0000 EECON xxxx xx00 C8h T2CON 0000 0000 T2MOD xxxx xx00 RCAP2L 0000 0000 C0h P4 xxxx xx11 B8h IPL0 x000 0000 B0h P3 1111 1111 A8h IEN0 0000 0000 A0h P2 1111 1111 98h SCON 0000 0000 90h P1 1111 1111 88h TCON 0000 0000 TMOD 0000 0000 TL0 0000 0000 TL1 0000 0000 80h P0 1111 1111 SP 0000 0111 DPL 0000 0000 DPH 0000 0000 0/8(1) 1/9 2/A 3/B CL 0000 0000 7/F FFh IPH1 xxxx x000 F7h EFh E7h CCAPM1 x000 0000 CCAPM2 x000 0000 CCAPM3 x000 0000 CCAPM4 x000 0000 DFh D7h RCAP2H 0000 0000 TL2 0000 0000 TH2 0000 0000 CANEN1 xx00 0000 CANEN2 0000 0000 CFh C7h SADEN 0000 0000 BFh IPH0 x000 0000 SADDR 0000 0000 B7h AFh AUXR1 0000 0000 WDTRST 1111 1111 WDTPRG xxxx x000 SBUF 0000 0000 A7h 9Fh 97h TH0 0000 0000 4/C TH1 0000 0000 5/D AUXR 0000 1000 6/E CKCON 0000 0000 8Fh PCON 0000 0000 87h 7/F Note: 2. These registers are bit-addressable. Sixteen addresses in the SFR space are both byte-addressable and bit-addressable. The bit-addressable SFR’s are those whose address ends in 0 and 8. The bit addresses, in this area, are 0x80 through to 0xFF. Draft.A - March 30, 2001 13 Preview - Confidential T89C51AC2 6. Clock 6.1. Introduction The T89C51AC2 core needs only 6 clock periods per machine cycle. This feature, called ”X2”, provides the following advantages: • • • • Divides frequency crystals by 2 (cheaper crystals) while keeping the same CPU power. Saves power consumption while keeping the same CPU power (oscillator power saving). Saves power consumption by dividing dynamic operating frequency by 2 in operating and idle modes. Increases CPU power by 2 while keeping the same crystal frequency. In order to keep the original C51 compatibility, a divider-by-2 is inserted between the XTAL1 signal and the main clock input of the core (phase generator). This divider may be disabled by the software. An extra feature is available for selected hardware in the X2 mode. This feature allows starting of the CPU in the X2 mode, without starting in the standard mode. The hardware CPU X2 mode can be read and write via IAP (SetX2mode, ClearX2mode, ReadX2mode), see InSystem Programming section. These IAPs are detailed in the "In-System Programming" section. 6.2. Description The clock for the whole circuit and peripheral is first divided by two before being used by the CPU core and peripherals. This allows any cyclic ratio to be accepted on the XTAL1 input. In X2 mode, as this divider is bypassed, the signals on XTAL1 must have a cyclic ratio between 40 to 60%. Figure 5. shows the clock generation block diagram. The X2 bit is validated on the XTAL1÷2 rising edge to avoid glitches when switching from the X2 to the STD mode. Figure 6 shows the mode switching waveforms. 14 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 PCON.0 X2 IDL CKCON.0 X2B Hardware byte ÷2 XTAL1 CPU Core Clock 0 1 XTAL2 CPU CLOCK PD CPU Core Clock Symbol PCON.1 ÷2 1 FT0 Clock 0 ÷2 1 FT1 Clock 0 ÷2 1 FT2 Clock 0 ÷2 1 FUart Clock 0 ÷2 1 FPca Clock 0 ÷2 1 FWd Clock 0 PERIPH CLOCK X2 CKCON.0 Peripheral Clock Symbol WDX2 PCAX2 SIX2 T2X2 T1X2 T0X2 CKCON.6 CKCON.5 CKCON.4 CKCON.3 CKCON.2 CKCON.1 Figure 5. Clock CPU Generation Diagram Draft.A - March 30, 2001 15 Preview - Confidential T89C51AC2 XTAL1 XTAL2 X2 bit CPU clock STD Mode X2 Mode STD Mode Figure 6. Mode Switching Waveforms The X2 bit in the CKCON register (See Table 7) allows switching from 12 clock cycles per instruction to 6 clock cycles and vice versa. At reset, the standard speed is activated (STD mode). Setting this bit activates the X2 feature (X2 mode). CAUTION In order to prevent any incorrect operation while operating in the X2 mode, users must be aware that all peripherals using the clock frequency as a time reference (UART, timers...) will have their time reference divided by two. For example a free running timer generating an interrupt every 20 ms will then generate an interrupt every 10 ms. A UART with a 4800 baud rate will have a 9600 baud rate. 16 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 6.3. Register CKCON (S:8Fh) Clock Control Register 7 6 5 4 3 2 1 0 - WDX2 PCAX2 SIX2 T2X2 T1X2 T0X2 X2 Bit Number Bit Mnemonic Description Reserved The value read from this bit is indeterminate. Do not set this bit. 7 - 6 WDX2 Watchdog clock (1) Clear to select 6 clock periods per peripheral clock cycle. Set to select 12 clock periods per peripheral clock cycle. 5 PCAX2 Programmable Counter Array clock (1) Clear to select 6 clock periods per peripheral clock cycle. Set to select 12 clock periods per peripheral clock cycle. 4 SIX2 Enhanced UART clock (MODE 0 and 2) (1) Clear to select 6 clock periods per peripheral clock cycle. Set to select 12 clock periods per peripheral clock cycle. 3 T2X2 Timer2 clock (1) Clear to select 6 clock periods per peripheral clock cycle. Set to select 12 clock periods per peripheral clock cycle. 2 T1X2 Timer1 clock (1) Clear to select 6 clock periods per peripheral clock cycle. Set to select 12 clock periods per peripheral clock cycle. 1 T0X2 Timer0 clock (1) Clear to select 6 clock periods per peripheral clock cycle. Set to select 12 clock periods per peripheral clock cycle. 0 X2 CPU clock Clear to select 12 clock periods per machine cycle (STD mode) for CPU and all the peripherals. Set to select 6 clock periods per machine cycle (X2 mode) and to enable the individual peripherals "X2"bits. NOTE: 1. This control bit is validated when the CPU clock bit X2 is set; when X2 is low, this bit has no effect. Reset Value = 0000 0000b Figure 7. CKCON Register Draft.A - March 30, 2001 17 Preview - Confidential T89C51AC2 7. Program/Code Memory 7.1. Introduction The T89C51AC2 implement 32 Kbytes of on-chip program/code memory. Figure 8 shows the split of internal and external program/code memory spaces depending on the product. The FLASH memory increases EPROM and ROM functionality by in-circuit electrical erasure and programming. Thanks to the internal charge pump, the high voltage needed for programming or erasing FLASH cells is generated on-chip using the standard VDD voltage. Thus, the FLASH Memory can be programmed using only one voltage and allows in application software programming commonly known as IAP. Hardware programming mode is also available using specific programming tool. FFFFh 32 Kbytes External Code 8000h 7FFFh1 32 Kbytes FLASH 0000h T89C51AC2 Figure 8. Program/Code Memory Organization Caution: 1. If the program executes exclusively from on-chip code memory (not from external memory), beware of executing code from the upper byte of on-chip memory (7FFFh) and thereby disrupt I/O Ports 0 and 2 due to external prefetch. Fetching code constant from this location does not affect Ports 0 and 2. 7.2. External Code Memory Access 7.2.1. 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 9 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 12 describes the external memory interface signals. 18 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 FLASH EPROM T89C51AC2 A15:8 P2 A15:8 ALE AD7:0 Latch P0 A7:0 A7:0 D7:0 PSEN# OE Figure 9. External Code Memory Interface Structure Table 12. External Data Memory Interface Signals Signal Name Type Alternate Function A15:8 O AD7:0 I/O ALE O Address Latch Enable ALE signals indicates that valid address information are available on lines AD7:0. - PSEN# O Program Store Enable Output This signal is active low during external code fetch or external code read (MOVC instruction). - Description Address Lines Upper address lines for the external bus. P2.7:0 Address/Data Lines Multiplexed lower address lines and data for the external memory. P0.7:0 7.2.2. External Bus Cycles This section describes the bus cycles the T89C51AC2 executes to fetch code (see Figure 10) in the external program/ code memory. External memory cycle takes 6 CPU clock periods. This is equivalent to 12 oscillator clock period in standard mode or 6 oscillator clock periods in X2 mode. For further information on X2 mode.(see the clock Section) For simplicity, the accompanying figure depicts the bus cycle waveforms in idealized form and do not provide precise timing information. CPU Clock ALE PSEN# P0 D7:0 P2 PCH PCL D7:0 PCL PCH D7:0 PCH Figure 10. External Code Fetch Waveforms Draft.A - March 30, 2001 19 Preview - Confidential T89C51AC2 7.3. FLASH Memory Architecture T89C51AC2 features two on-chip flash memories: • Flash memory FM0: containing 32 Kbytes of program memory (user space) organized into 128 byte pages, • Flash memory FM1: 2 Kbytes for boot loader and Application Programming Interfaces (API). The FM0 supports both parallel programming and Serial In-System Programming (ISP) whereas FM1 supports only parallel programming by programmers. The ISP mode is detailed in the "In-System Programming" section. All Read/Write access operations on FLASH Memory by user application are managed by a set of API described in the "In-System Programming" section. 2 Kbytes Flash memory boot space Hardware Security (1 byte) Extra Row (128 bytes) Column Latches (128 bytes) FM1 7FFFh 32 Kbytes FFFFh F800h FM1 mapped between FFFFh and F800h when bit ENBOOT is set in AUXR1 register Flash memory user space FM0 0000h Figure 11. Flash memory architecture 7.3.1. FM0 Memory Architecture The flash memory is made up of 4 blocks (see Figure 11): 1. The memory array (user space) 32 Kbytes 2. The Extra Row 3. The Hardware security bits 4. The column latch registers 7.3.1.1. User Space This space is composed of a 32 Kbytes FLASH memory organized in 256 pages of 128 bytes. It contains the user’s application code. 7.3.1.2. Extra Row (XRow) This row is a part of FM0 and has a size of 128 bytes. The extra row may contain information for boot loader usage. 20 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 7.3.1.3. Hardware security space The Hardware security space is a part of FM0 and has a size of 1 byte. The 4 MSB can be read/written by software, the 4 LSB can only be read by software and written by hardware in parallel mode. 7.3.1.4. Column latches The column latches, also part of FM0, have a size of full page (128 bytes). The column latches are the entrance buffers of the three previous memory locations (user array, XROW and Hardware security byte). Draft.A - March 30, 2001 21 Preview - Confidential T89C51AC2 7.4. Overview of FM0 operations The CPU interfaces to the flash memory through the FCON register and AUXR1 register. These registers are used to: • • • • Map the memory spaces in the adressable space Launch the programming of the memory spaces Get the status of the flash memory (busy/not busy) Select the flash memory FM0/FM1. 7.4.1. Mapping of the memory space By default, the user space is accessed by MOVC instruction for read only. The column latches space is made accessible by setting the FPS bit in FCON register. Writing is possible from 0000h to 7FFFh, address bits 6 to 0 are used to select an address within a page while bits 14 to 7 are used to select the programming address of the page. Setting this bit takes precedence on the EXTRAM bit in AUXR register. The other memory spaces (user, extra row, hardware security) are made accessible in the code segment by programming bits FMOD0 and FMOD1 in FCON register in accordance with Table 13. A MOVC instruction is then used for reading these spaces. Table 13. .FM0 blocks select bits FMOD1 FMOD0 FM0 Adressable space 0 0 User (0000h-FFFFh) 0 1 Extra Row(FF80h-FFFFh) 1 0 Hardware Security (0000h) 1 1 reserved 7.4.2. Launching programming FPL3:0 bits in FCON register are used to secure the launch of programming. A specific sequence must be written in these bits to unlock the write protection and to launch the programming. This sequence is 5 followed by A. Table 14 summarizes the memory spaces to program according to FMOD1:0 bits. Table 14. Programming spaces Write to FCON Operation User Extra Row Security Space Reserved FPL3:0 FPS FMOD1 FMOD0 5 X 0 0 No action A X 0 0 Write the column latches in user space 5 X 0 1 No action A X 0 1 Write the column latches in extra row space 5 X 1 0 No action A X 1 0 Write the fuse bits space 5 X 1 1 No action A X 1 1 No action The FLASH memory enters a busy state as soon as programming is launched. In this state, the memory is no more available for fetching code. Caution: Interrupts that may occur during programming time must be disable to avoid any spurious exit of the idle mode. 22 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 7.4.3. Status of the flash memory The bit FBUSY in FCON register is used to indicate the status of programming. FBUSY is set when programming is in progress. 7.4.4. Selecting FM0/FM1 The bit ENBOOT in AUXR1 register is used to choose between FM0 and FM1 mapped up to F800h. Draft.A - March 30, 2001 23 Preview - Confidential T89C51AC2 7.4.5. Loading the Column Latches Any number of data from 1 byte to 128 bytes can be loaded in the column latches. This provides the capability to program the whole memory by byte, by page or by any number of bytes in a page. When programming is launched, an automatic erase of the locations loaded in the column latches is first performed, then programming is effectively done. Thus no page or block erase is needed and only the loaded data are programmed in the corresponding page. The following procedure is used to load the column latches and is summarized in Figure 12: • • • • • Map the column latch space by setting FPS bit. Load the DPTR with the address to load. Load Accumulator register with the data to load. Execute the MOVX @DPTR, A instruction. If needed loop the three last instructions until the page is completely loaded. Column Latches Loading Column Latches Mapping FPS= 1 Data Load DPTR= Address ACC= Data Exec: MOVX @DPTR, A Last Byte to load? Data memory Mapping FPS= 0 Figure 12. Column Latches Loading Procedure 24 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 7.4.6. Programming the FLASH Spaces User The following procedure is used to program the User space and is summarized in Figure 13: • Load data in the column latches from address 0000h to 7FFFh1. • Disable the interrupts. • Launch the programming by writing the data sequence 50h followed by A0h in FCON register. The end of the programming indicated by the FBUSY flag cleared. • Enable the interrupts. Note: 1. The last page address used when loading the column latch is the one used to select the page programming address. Extra Row The following procedure is used to program the Extra Row space and is summarized in Figure 13: • Load data in the column latches from address FF80h to FFFFh. • Disable the interrupts. • Launch the programming by writing the data sequence 52h followed by A2h in FCON register. The end of the programming indicated by the FBUSY flag cleared. • Enable the interrupts. Draft.A - March 30, 2001 25 Preview - Confidential T89C51AC2 FLASH Spaces Programming Column Latches Loading see Figure 12 Disable IT EA= 0 Launch Programming FCON= 5xh FCON= Axh FBusy Cleared? Erase Mode FCON = 00h End Programming Enable IT EA= 1 Figure 13. Flash and Extra row Programming Procedure 26 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 Hardware Security The following procedure is used to program the Hardware Security space and is summarized in Figure 14: • • • • • • Set FPS and map Harware byte (FCON = 0x0C) Disable the interrupts. Load DPTR at address 0000h. Load Accumulator register with the data to load. Execute the MOVX @DPTR, A instruction. Launch the programming by writing the data sequence 54h followed by A4h in FCON register. The end of the programming indicated by the FBusy flag cleared. • Enable the interrupts. FLASH Spaces Programming FCON = 0Ch Data Load DPTR= 00h ACC= Data Exec: MOVX @DPTR, A Disable IT EA= 0 Launch Programming FCON= 54h FCON= A4h FBusy Cleared? Erase Mode FCON = 00h End Programming Enable IT EA= 1 Figure 14. Hardware Programming Procedure Draft.A - March 30, 2001 27 Preview - Confidential T89C51AC2 7.4.7. Reading the FLASH Spaces User The following procedure is used to read the User space and is summarized in Figure 15: • Map the User space by writing 00h in FCON register. • Read one byte in Accumulator by executing MOVC A,@A+DPTR with A= 0 & DPTR= 0000h to FFFFh. Extra Row The following procedure is used to read the Extra Row space and is summarized in Figure 15: • Map the Extra Row space by writing 02h in FCON register. • Read one byte in Accumulator by executing MOVC A,@A+DPTR with A= 0 & DPTR= FF80h to FFFFh. Hardware Security The following procedure is used to read the Hardware Security space and is summarized in Figure 15: • Map the Hardware Security space by writing 04h in FCON register. • Read the byte in Accumulator by executing MOVC A,@A+DPTR with A= 0 & DPTR= 0000h. FLASH Spaces Reading FLASH Spaces Mapping FCON= 00000xx0b Data Read DPTR= Address ACC= 0 Exec: MOVC A, @A+DPTR Erase Mode FCON = 00h Figure 15. Reading Procedure 28 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 7.5. Registers FCON (S:D1h) FLASH Control Register 7 6 5 4 3 2 1 0 FPL3 FPL2 FPL1 FPL0 FPS FMOD1 FMOD0 FBUSY Bit Number Bit Mnemonic 7-4 FPL3:0 3 FPS 2-1 FMOD1:0 0 FBUSY Description Programming Launch Command Bits Write 5Xh followed by AXh to launch the programming according to FMOD1:0. (see Table 14.) FLASH Map Program Space Set to map the column latch space in the data memory space. Clear to re-map the data memory space. FLASH Mode See Table 13 or Table 14. FLASH Busy Set by hardware when programming is in progress. Clear by hardware when programming is done. Can not be cleared by software. Reset Value= 0000 0000b Figure 16. FCON Register Draft.A - March 30, 2001 29 Preview - Confidential T89C51AC2 8. Data Memory 8.1. Introduction The T89C51AC2 provides data memory access in two 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 1024 bytes RAM segment (ERAM). 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. Figure 17 shows the internal and external data memory spaces organization. FFFFh 64 Kbytes External XRAM FFh FFh or 3FFh 256 up to 1024 bytes Internal ERAM EXTRAM= 0 00h 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 0100h up to 0400h 0000h EXTRAM= 1 Figure 17. Internal and External Data Memory Organization 30 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 8.2. Internal Space 8.2.1. Lower 128 Bytes RAM The lower 128 bytes of RAM (see Figure 17) 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). Two bits RS0 and RS1 in PSW register (see Figure 23) 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 0 from 08h to 0Fh 1 0 Register bank 0 from 10h to 17h 1 1 Register bank 0 from 18h to 1Fh 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. 7Fh 30h 2Fh 20h 18h 10h 08h 00h Bit-Addressable Space (Bit Addresses 0-7Fh) 1Fh 17h 0Fh 4 Banks of 8 Registers R0-R7 07h Figure 18. Lower 128 bytes Internal RAM Organization 8.2.2. Upper 128 Bytes RAM The upper 128 bytes of RAM are accessible from address 80h to FFh using only indirect addressing mode. 8.2.3. Expanded RAM The on-chip 1024 bytes of expanded RAM (ERAM) are accessible from address 0000h to 03FFh using indirect addressing mode through MOVX instructions. In this address range, the bit EXTRAM in AUXR register is used to select the ERAM (default) or the XRAM. As shown in Figure 17 when EXTRAM= 0, the ERAM is selected and when EXTRAM= 1, the XRAM is selected. Caution: 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. Draft.A - March 30, 2001 31 Preview - Confidential T89C51AC2 8.3. External Space 8.3.1. 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). Figure 19 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 16 describes the external memory interface signals. RAM PERIPHERAL <Generic A15:8 P2 A15:8 ALE AD7:0 P0 Latch A7:0 A7:0 D7:0 RD# WR# OE WR Figure 19. External Data Memory Interface Structure Table 16. External Data Memory Interface Signals Signal Name Type Description Alternative Function A15:8 O AD7:0 I/O 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 Address Lines Upper address lines for the external bus. P2.7:0 Address/Data Lines Multiplexed lower address lines and data for the external memory. P0.7:0 - 8.3.2. External Bus Cycles This section describes the bus cycles the T89C51AC2 executes to read (see Figure 20), and write data (see Figure 21) in the external data memory. External memory cycle takes 6 CPU clock periods. This is equivalent to 12 oscillator clock period in standard mode or 6 oscillator clock periods in X2 mode. For further information on X2 mode. 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. 32 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 For simplicity, the accompanying figures 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” of the T89C51AC2 datasheet. CPU Clock ALE RD#1 P0 P2 DPL or Ri D7:0 DPH or P22,3 P2 Figure 20. External Data Read Waveforms Notes: 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. CPU Clock ALE WR#1 P0 P2 DPL or Ri P2 D7:0 DPH or P22,3 Figure 21. External Data Write Waveforms Notes: 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. Draft.A - March 30, 2001 33 Preview - Confidential T89C51AC2 8.4. Dual Data Pointer 8.4.1. Description The T89C51AC2 implements a second data pointer for speeding up code execution and reducing code size in case of intensive usage of external memory accesses. 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 Figure 25) is used to select whether DPTR is the data pointer 0 or the data pointer 1 (see Figure 22). DPL0 0 DPL1 1 DPL DPTR0 DPS DPTR1 DPH0 0 DPH1 1 AUXR1.0 DPTR DPH Figure 22. Dual Data Pointer Implementation 8.4.2. 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. Hereafter is an example of block move implementation using the two pointers and coded in assembler. Latest C compiler take also 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 EQU 0A2h move: mov inc mov inc movx inc inc movx inc jnz DPTR,#SOURCE AUXR1 DPTR,#DEST AUXR1 A,@DPTR DPTR AUXR1 @DPTR,A DPTR mv_loop 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 end_move: 34 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 8.5. Registers 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 Figure 23. PSW Register Draft.A - March 30, 2001 35 Preview - Confidential T89C51AC2 AUXR (S:8Eh) Auxiliary Register 7 6 5 4 3 2 1 0 - - M0 - XRS1 XRS0 EXTRAM A0 Bit Number Bit Mnemonic 7-6 - 5 M0 4 - 3-2 XRS1-0 1 EXTRAM 0 A0 Description Reserved The value read from these bits are indeterminate. Do not set this bit. Stretch MOVX control: the RD/ and the WR/ pulse length is increased according to the value of M0. M0 Pulse length in clock period 0 6 1 30 Reserved The value read from this bit is indeterminate. Do not set this bit. ERAM size: Accessible size of the ERAM XRS1:0 ERAM size 0 0 256 bytes 0 1 512 bytes 1 0 768 bytes 1 1 1024 bytes (default) Internal/External RAM (00h - FFh) access using MOVX @ Ri /@ DPTR 0 - Internal ERAM access using MOVX @ Ri / @ DPTR. 1 - External data memory access. Disable/Enable ALE) 0 - ALE is emitted at a constant rate of 1/6 the oscillator frequency (or 1/3 if X2 mode is used) 1 - ALE is active only during a MOVX or MOVC instruction. Reset Value= X00X 1100b Not bit addressable Figure 24. AUXR Register 36 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 AUXR1 (S:A2h) Auxiliary Control Register 1. 7 6 5 4 3 2 1 0 - - ENBOOT - GF3 0 - DPS Bit Number Bit Mnemonic Description Reserved The value read from these bits is indeterminate. Do not set these bits. 7-6 - 5 ENBOOT 4 - 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 Enable Boot Flash Set this bit for map the boot flash between F800h -FFFFh Clear this bit for disable boot flash. Reserved The value read from this bit is indeterminate. Do not set this bit. General Purpose Flag 3. Data Pointer Select Bit Set to select second dual data pointer: DPTR1. Clear to select first dual data pointer: DPTR0. Reset Value= XXXX 00X0b Figure 25. AUXR1 Register Draft.A - March 30, 2001 37 Preview - Confidential T89C51AC2 9. EEPROM data memory 9.1. General description The 2k byte on-chip EEPROM memory block is located at addresses 0000h to 07FFh of the XRAM memory space and is selected by setting control bits in the EECON register. A read in the EEPROM memory is done with a MOVX instruction. A physical write in the EEPROM memory is done in two steps: write data in the column latches and transfer of all data latches into an EEPROM memory row (programming). The number of data written on the page may vary from 1 to 128 bytes (the page size). When programming, only the data written in the column latch is programmed and a ninth bit is used to obtain this feature. This provides the capability to program the whole memory by bytes, by page or by a number of bytes in a page. Indeed, each ninth bit is set when the writing the corresponding byte in a row and all these ninth bits are reset after the writing of the complete EEPROM row. 9.2. Write Data in the column latches Data is written by byte to the column latches as for an external RAM memory. Out of the 11 address bits of the data pointer, the 4 MSBs are used for page selection (row) and 7 are used for byte selection. Between two EEPROM programming sessions, all the addresses in the column latches must stay on the same page, meaning that the 4 MSB must no be changed. The following procedure is used to write to the column latches: • • • • • Set bit EEE of EECON register Load DPTR with the address to write Store A register with the data to be written Execute a MOVX @DPTR, A If needed loop the three last instructions until the end of a 128 bytes page 9.3. Programming The EEPROM programming consists on the following actions: • writing one or more bytes of one page in the column latches. Normally, all bytes must belong to the same page; if not, the first page address will be latched and the others discarded. • launching programming by writing the control sequence (54h followed by A4h) to the EECON register. • EEBUSY flag in EECON is then set by hardware to indicate that programming is in progress and that the EEPROM segment is not available for reading. • The end of programming is indicated by a hardware clear of the EEBUSY flag. 38 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 9.4. Read Data The following procedure is used to read the data stored in the EEPROM memory: • Set bit EEE of EECON register • Load DPTR with the address to read • Execute a MOVX A, @DPTR Draft.A - March 30, 2001 39 Preview - Confidential T89C51AC2 9.5. Registers EECON (S:0D2h) EEPROM Control Register 7 6 5 4 3 2 1 0 EEPL3 EEPL2 EEPL1 EEPL0 - - EEE EEBUSY Bit Number Bit Mnemonic 7-4 EEPL3-0 3 - Reserved The value read from this bit is indeterminate. Do not set this bit. 2 - Reserved The value read from this bit is indeterminate. Do not set this bit. 1 EEE 0 EEBUSY Description Programming Launch command bits Write 5Xh followed by AXh to EEPL to launch the programming. Enable EEPROM Space bit Set to map the EEPROM space during MOVX instructions (Write in the column latches) Clear to map the XRAM space during MOVX. Programming Busy flag Set by hardware when programming is in progress. Cleared by hardware when programming is done. Can not be set or cleared by software. Reset Value= XXXX XX00b Not bit addressable Figure 26. EECON Register 40 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 10. In-System-Programming (ISP) 10.1. Introduction With the implementation of the User ROM and the Boot ROM in Flash technology the T89C51AC2 allows the system engineer the development of applications with a very high level of flexibility. This flexibility is based on the possibility to alter the customer programming on all stages of a product’s life: • During the final production phase, the 1st personalization of the product by parallel or serial charging of the code in the User ROM and if wanted also a customized Boot loader in the Boot memory (Atmel will provide also a standard Boot loader by default). • After assembling of the product in its final, embedded position by serial mode via the UART. This In-System-Programming (ISP) allows code modification over the total lifetime of the product. Besides the default Boot loader Atmel will provide to the customer also all the needed Application-ProgrammingInterfaces (API) which are needed for the ISP. The API will be located also in the Boot memory. This will allow the customer to have a full use of the 32 Kbyte user memory. Two blocks flash memories are implemented (see Figure 27): • Flash memory FM0: containing 32 Kbytes of program memory organized in page of 128 bytes, • Flash memory FM1: 2 Kbytes for default boot loader and Application Programming Interfaces (API). The FM0 supports both, hardware (parallel) and software programming whereas FM1 supports only hardware programming. The ISP functions are assumed by: • FCON register & bit ENBOOT in AUXR1 register, • Software Boot Vector (SBV), which can be read and modified by using an API or the parallel programming mode (see Figure 30) The SBV is stored in XROW. • The Fuse bit Boot Loader Jump Bit (BLJB) can be read and modified using an API or the parallel programming mode. The BLJB is located in the Hardware security byte (see Figure 32). • The Extra Byte (EB) and Boot Status Byte (BSB) can be modified only by using API (see Figure 32). EB is stored in XROW The bit ENBOOT in AUXR1 register allows to map FM1 between address F800h and FFFFh of FM0. The FM0 can be programed by: - The Atmel boot loader, located by default in FM1. - The user boot loader located in FM0 - The user boot loader located in FM1 in place of Atmel boot loader. API contained in FM1 can be called by the user boot loader located in FM0 at the address [SBV]00h. The user program simply calls the common entry point with appropriate parameters in FM1 to accomplish the desired operation (all these methods will describe in Application Notes on api-description). Boot Flash operations include: erase block, program byte or page, verify byte or page, program security lock bit, etc. Indeed, Atmel provides the binary code of the default Flash boot loader. Draft.A - March 30, 2001 41 Preview - Confidential T89C51AC2 10.2. Flash Programming and Erasure There are three methods of programming the Flash memory: • The Atmel bootloader located in FM1 is activated by the application. Low level API routines (located in FM1) to program FM0 will be used. The interface used for serial downloading to FM0 is the UART. API can be called also by user’s bootloader located in FM0 at [SBV]00h. • A further method exist in activating the Atmel boot loader by hardware activation. • The FM0 can be programed also by the parallel mode using a programmer. FFFFh F800h 2 Kbytes IAP bootloader FM1 7FFFh Custom Boot Loader FM1 mapped between FFFF and F800 when API called [SBV]00h 32 Kbytes Flash memory FM0 0000h Figure 27. Flash Memory Mapping 42 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 10.2.1. Flash Parallel Programming The three lock bits in Hardware byte are programmed according to Table, will provide different level of protection for the on-chip code and data located in FM0 and FM1. The only way for write this bits are the parallel mode. Table 17. Program Lock bit Program Lock Bits Protection description Security level LB0 LB1 LB2 1 U U U No program lock features enabled. MOVC instruction executed from external program memory returns non encrypted data. 2 P U U MOVC instruction executed from external program memory are disabled from fetching code bytes from internal memory, EA is sampled and latched on reset, and further parallel programming of the Flash is disabled. 3 U P U Same as 2, also verify through parallel programming interface is disabled. 4 U U P Same as 3, also external execution is disabled. Program Lock bits U: unprogrammed P: programmed WARNING: Security level 2 and 3 should only be programmed after Flash and Core verification. Program Lock bits These security bits protect the code access through the parallel programming interface. They are set by default to level 4. Draft.A - March 30, 2001 43 Preview - Confidential T89C51AC2 10.3 Boot Process 10.3.1. Software boot process example Many algorithms can be used for the software boot process. Before describing them, some explanations are needed for the utility of different flags and bytes available. Boot Loader Jump Bit (BLJB): - This bit indicates if on RESET the user wants jump on his application at address @0000h on FM0 or execute the boot loader at address @F800h on FM1. - BLJB = 0 on parts delivered with bootloader programmed. - To read or modified this bit, the APIs are used. Boot Vector Address (SBV): - This byte contains the msb of the user boot loader address in FM0. - The default value of SBV is FFh (no user boot loader in FM0). - To read or modified this byte, the APIs are used. Extra Byte (EB) & Boot Status Byte (BSB): - These bytes are reserved for customer use. - To read or modified this byte, the APIs are used. Example of software boot process in FM1 (see Figure 29) In this example the Extra Byte (EB) is a configuration bit which forces the user boot loader execution even on the hardware condition. 10.3.2. Hardware boot process At the falling edge of RESET, the bit ENBOOT in AUXR1 register is initialized with the value of Boot Loader Jump Bit (BLJB). Further at the falling edge of RESET if the following conditions (called Hardware condition) are detected: • PSEN low, • EA high, • ALE high (or not connected). FCON register is initialized with the value 00h and the program in FM1 can be executed. The Hardware condition allows jump in bootloader (FM1) whatever BLJB value. If no hardware condition is detected, the FCON register is initialized with the value F0h. Check of the BLJB value. • If bit BLJB is cleared (BLJB = 1): User application in FM0 will be started at @0000h (standard reset). • If bit BLJB is set (BLJB = 0): Boot loader will be started at @F800h in FM1. 44 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 bit ENBOOT in AUXR1 register is initialized with BLJB. RESET ENBOOT = 1 PC = F800h FCON = 00h Hardware Hardware condition? ENBOOT = 0 PC = 0000h No No Yes FCON = F0h BLJB == 0 ? Yes Software USER APPLICATION ENBOOT = 1 PC = F800h Boot Loader in FM1 Figure 28. Hardware Boot Process Algorithm Draft.A - March 30, 2001 45 Preview - Confidential T89C51AC2 bit ENBOOT in AUXR1 register is initialized with BLJB (Fuse bit). Hardware boot process RESET ENBOOT = 1 PC = F800h FCON = 00h Hardware condition? No No Yes FCON = F0h BLJB == 0 ? Yes ENBOOT = 1 PC = F800h USER APPLICATION Software boot process Yes SBV < 3Fh ? FCON == 00h ? No No Yes USER BOOT LOADER DEFAULT BOOT LOADER Figure 29. Example of Software Boot process 46 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 10.4. 2 Application-Programming-Interface Several Application Program Interface (API) calls are available for use by an application program to permit selective erasing and programming of FLASH pages. All calls are made by functions. All these APIs will be describe in an application note. API CALL PROGRAM DATA BYTE PROGRAM DATA PAGE PROGRAM EEPROM BYTE ERASE BLOCK ERASE BOOT VECTOR (SBV) Description Write a byte in flash memory Write a page (128 bytes) in flash memory Write a byte in Eeprom memory Erase all flash memory Erase the boot vector PROGRAM BOOT VECTOR (SBV) Write the boot vector PROGRAM EXTRA BYTE (EB) Write the extra byte READ DATA BYTE READ EEPROM BYTE READ FAMILY CODE READ MANUFACTURER CODE READ PRODUCT NAME READ REVISION NUMBER READ STATUS BIT (BSB) Read the status bit READ BOOT VECTOR (SBV) Read the boot vector READ EXTRA BYTE (EB) Read the extra byte PROGRAM X2 READ X2 Write the hardware flag for X2 mode Read the hardware flag for X2 mode PROGRAM BLJB Write the hardware flag BLJB READ BLJB Read the hardware flag BLJB Draft.A - March 30, 2001 47 Preview - Confidential T89C51AC2 10.5. Application remarks • After loading a new program using by the boot loader, the BLJB bit must be set to allow user application to start at RESET. • A user bootloader can be mapped at address [SBV]00h. The byte SBV contains the high byte of the boot address, and can be read and written by API. • The API can be called during user application, without disabling interrupt. The interrupts are disabled by some APIs, for complex operations. 48 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 10.6. XROW Bytes Mnemonic Description Default value Address SBV Boot Vector Address F8h 01h SSB Software Security Byte FFh 05h EB Extra Byte FFh 06h Copy of the Manufacturer Code 58h 30h Copy of the Device ID#1: Family code D7h 31h Copy of the Device ID#2:Memories size and type F7h 60h Copy of the Device ID#3:Name and Revision FFh 61h Table 18. Xrow mapping SBV register Software Boot Vector 7 6 5 4 3 2 1 0 ADD 7 ADD 6 ADD 5 ADD 4 ADD 3 ADD 2 ADD 1 ADD 0 Bit Number Bit Mnemonic 7-0 ADD7:0 Description MSB of user boot loader address location Default value after erasing chip: FFh NOTE: Only accessed by the API or in the parallel programming mode. Figure 30. SBV Register EB register EXTRA BYTE 7 6 5 4 3 2 1 0 - - - - - - - - Bit Number Bit Mnemonic 7-0 - Description User definition Default value after erasing chip: FFh NOTE: TOnly accessed by the API or in the parallel programming mode. Figure 31. EB Register Draft.A - March 30, 2001 49 Preview - Confidential T89C51AC2 10.7. Hardware Byte 7 6 5 4 3 2 1 0 X2B BLJB - - - LB2 LB1 LB0 Bit Number Bit Mnemonic Description 7 X2B X2 Bit Set this bit to start in standard mode Clear this bit to start in X2 mode. 6 BLJB Boot Loader JumpBit Clear (=1)this bit to start the user’s application on next RESET (@0000h) located in FM0, Set (=0)this bit to start the boot loader(@F800h) located in FM1. 5-3 - 2-0 LB2:0 Reserved The value read from these bits are indeterminate. Lock Bits Default value after erasing chip: FFh NOTE: Only the 4 MSB bits can be access by software. The 4 LSB bits can only be access by parallel mode. Figure 32. Hardware byte 50 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 11. Serial I/O Port The T89C51AC2 I/O serial port is compatible with the I/O serial port in the 80C52. It provides both synchronous and asynchronous communication modes. It operates as a Universal Asynchronous Receiver and Transmitter (UART) in three full-duplex modes (Modes 1, 2 and 3). Asynchronous transmission and reception can occur simultaneously and at different baud rates Serial I/O port includes the following enhancements: • Framing error detection • Automatic address recognition IB Bus Write SBUF Read SBUF SBUF Receiver SBUF Transmitter TXD Load SBUF Mode 0 Transmit Receive Shift register RXD Serial Port Interrupt Request RI TI SCONI/O Port Block Diagram Figure 33. Serial 11.1. Framing Error Detection Framing bit error detection is provided for the three asynchronous modes. To enable the framing bit error detection feature, set SMOD0 bit in PCON register. SM0/FE SM1 SM2 REN TB8 RB8 TI RI Set FE bit if stop bit is 0 (framing error) SM0 to UART mode control SMOD1 SMOD0 - POF GF1 GF0 PD IDL To UART framing error control Figure 34. Framing Error Block Diagram 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 two CPUs. If a valid stop bit is not found, the Framing Error bit (FE) in SCON register bit is set. Draft.A - March 30, 2001 51 Preview - Confidential T89C51AC2 The software may examine the FE bit after each reception to check for data errors. Once set, only software or a reset clears the FE bit. Subsequently received frames with valid stop bits cannot clear the FE bit. When the FE feature is enabled, RI rises on the stop bit instead of the last data bit (See Figure 35. and Figure 36.). RXD D0 D1 D2 Start bit D3 D4 D5 D6 D7 Data byte Stop bit RI SMOD0=X FE SMOD0=1 Figure 35. UART Timing in Mode 1 RXD D0 Start bit D1 D2 D3 D4 D5 D6 Data byte D7 D8 NinthStop bit bit RI SMOD0=0 RI SMOD0=1 FE SMOD0=1 Figure 36. UART Timing in Modes 2 and 3 11.2. 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 the 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 will the receiver set the RI bit in the SCON register to generate an interrupt. This ensures that the CPU is not interrupted by command frames addressed to other devices. If necessary, you can enable the automatic address recognition feature in mode 1. 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: 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). 52 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 11.3. Given Address Each device has an individual address that is specified in the 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 SADEN Given 0101 0110b 1111 1100b 0101 01XXb Here is an example of how to use given addresses to address different slaves: Slave A: SADDR SADEN Given 1111 0001b 1111 1010b 1111 0X0Xb Slave B: SADDR SADEN Given 1111 0011b 1111 1001b 1111 0XX1b Slave C: SADDR SADEN Given 1111 0010b 1111 1101b 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). 11.4. 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 SADEN SADDR OR SADEN 0101 0110b 1111 1100b 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 SADEN Given 1111 0001b 1111 1010b 1111 1X11b, Slave B: SADDR SADEN Given 1111 0011b 1111 1001b 1111 1X11B, Slave C: SADDR= SADEN Given 1111 0010b 1111 1101b 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 an address FFh. To communicate with slaves A and B, but not slave C, the master can send and address FBh. Draft.A - March 30, 2001 53 Preview - Confidential T89C51AC2 11.5. REGISTERS SCON (S:98h) Serial Control Register 7 6 5 4 3 2 1 0 FE/SM0 SM1 SM2 REN TB8 RB8 TI RI Bit Number Bit Mnemonic 7 FE Description Framing Error bit (SMOD0=1) Clear to reset the error state, not cleared by a valid stop bit. Set by hardware when an invalid stop bit is detected. SM0 Serial port Mode bit 0 (SMOD0=0) Refer to SM1 for serial port mode selection. 6 SM1 Serial port Mode bit 1 SM0 SM1 0 0 0 1 1 0 1 1 5 SM2 Serial port Mode 2 bit / Multiprocessor Communication Enable bit Clear to disable multiprocessor communication feature. Set to enable multiprocessor communication feature in mode 2 and 3. 4 REN Reception Enable bit Clear to disable serial reception. Set to enable serial reception. 3 TB8 Transmitter Bit 8 / Ninth bit to transmit in modes 2 and 3 Clear to transmit a logic 0 in the 9th bit. Set to transmit a logic 1 in the 9th bit. 2 RB8 Receiver Bit 8 / Ninth bit received in modes 2 and 3 Cleared by hardware if 9th bit received is a logic 0. Set by hardware if 9th bit received is a logic 1. ModeBaud Rate Shift RegisterFXTAL/12 8-bit UARTVariable 9-bit UARTFXTAL/64 or FXTAL/32 9-bit UARTVariable 1 TI Transmit Interrupt flag Clear to acknowledge interrupt. Set by hardware at the end of the 8th bit time in mode 0 or at the beginning of the stop bit in the other modes. 0 RI Receive Interrupt flag Clear to acknowledge interrupt. Set by hardware at the end of the 8th bit time in mode 0, see Figure 35. and Figure 36. in the other modes. Reset Value = 0000 0000b Bit addressable Figure 37. SCON Register 54 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 SADEN (S:B9h) Slave Address Mask Register 7 6 5 4 3 Bit Number Bit Mnemonic 7-0 2 1 0 2 1 0 2 1 0 Description Mask Data for Slave Individual Address Reset Value = 0000 0000b Not bit addressable Figure 38. SADEN Register SADDR (S:A9h) Slave Address Register 7 6 5 4 3 Bit Number Bit Mnemonic 7-0 Description Slave Individual Address Reset Value = 0000 0000b Not bit addressable Figure 39. SADDR Register SBUF (S:99h) Serial Data Buffer 7 6 5 4 Bit Number Bit Mnemonic 7-0 3 Description Data sent/received by Serial I/O Port Reset Value = 0000 0000b Not bit addressable Figure 40. SBUF Register Draft.A - March 30, 2001 55 Preview - Confidential T89C51AC2 PCON (S:87h) Power Control Register 7 6 5 4 3 2 1 0 SMOD1 SMOD0 - POF 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 Clear to select SM0 bit in SCON register. Set to select FE bit in SCON register. 5 - 4 POF Power-Off Flag Clear to recognize next reset type. Set by hardware when VCC rises from 0 to its nominal voltage. Can also be set by software. 3 GF1 General purpose Flag Cleared by user for general purpose usage. Set by user for general purpose usage. 2 GF0 General purpose Flag Cleared by user for general purpose usage. Set by user for general purpose usage. 1 PD Power-Down mode bit Cleared by hardware when reset occurs. Set to enter power-down mode. 0 IDL Idle mode bit Clear by hardware when interrupt or reset occurs. Set to enter idle mode. Reserved The value read from this bit is indeterminate. Do not set this bit. Reset Value = 00X1 0000b Not bit addressable Figure 41. PCON Register 56 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 12. Timers/Counters 12.1. Introduction The T89C51AC2 implements two 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. 12.2. 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 Figure 47) 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 divided-down 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. 12.3. Timer 0 Timer 0 functions as either a Timer or event Counter in four modes of operation. Figure 42 to Figure 45 show the logical configuration of each mode. Timer 0 is controlled by the four lower bits of TMOD register (see Figure 48) and bits 0, 1, 4 and 5 of TCON register (see Figure 47). TMOD register selects the method of Timer gating (GATE0), Timer or Counter operation (T/C0#) 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. 12.3.1. Mode 0 (13-bit Timer) Mode 0 configures Timer 0 as an 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 42). The upper three bits of TL0 register are indeterminate and should be ignored. Prescaler overflow increments TH0 register. Draft.A - March 30, 2001 57 Preview - Confidential T89C51AC2 PERIPH CLOCK ÷6 0 THx (8 bits) 1 TLx (5 bits) Overflow TFx TCON reg Timer x Interrupt Request Tx C/Tx# TMOD reg INTx# GATEx TRx TMOD reg TCON reg Figure 42. Timer/Counter x (x= 0 or 1) in Mode 0 12.3.2. 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 43). The selected input increments TL0 register. PERIPH CLOCK ÷6 0 THx (8 bits) 1 TLx (8 bits) Overflow TFx TCON reg Timer x Interrupt Request Tx C/Tx# TMOD reg INTx# GATEx TRx TMOD reg TCON reg Figure 43. Timer/Counter x (x= 0 or 1) in Mode 1 12.3.3. 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 Figure 44). 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. PERIPH CLOCK ÷6 0 TLx (8 bits) 1 Overflow TFx TCON reg Timer x Interrupt Request Tx C/Tx# TMOD reg INTx# GATEx TMOD reg TRx THx (8 bits) TCON reg Figure 44. Timer/Counter x (x= 0 or 1) in Mode 2 58 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 12.3.4. Mode 3 (Two 8-bit Timers) Mode 3 configures Timer 0 such that registers TL0 and TH0 operate as separate 8-bit Timers (see Figure 45). 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 FPER /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. PERIPH CLOCK ÷6 0 1 TL0 (8 bits) Overflow TH0 (8 bits) Overflow TF0 TCON.5 Timer 0 Interrupt Request T0 C/T0# TMOD.2 INT0# GATE0 TMOD.3 PERIPH CLOCK TR0 TCON.4 ÷6 TF1 TCON.7 Timer 1 Interrupt Request TR1 TCON.6 Figure 45. Timer/Counter 0 in Mode 3: Two 8-bit Counters 12.4. Timer 1 Timer 1 is identical to Timer 0 excepted for Mode 3 which is a hold-count mode. Following comments help to understand the differences: • Timer 1 functions as either a Timer or event Counter in three modes of operation. Figure 42 to Figure 44 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 48) and bits 2, 3, 6 and 7 of TCON register (see Figure 47). 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. • 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 Timer/Counter before changing mode. 12.4.1. 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 modulo32 prescaler implemented with the lower 5 bits of the TL1 register (see Figure 42). The upper 3 bits of TL1 register are ignored. Prescaler overflow increments TH1 register. Draft.A - March 30, 2001 59 Preview - Confidential T89C51AC2 12.4.2. 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 43). The selected input increments TL1 register. 12.4.3. 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 44). 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. 12.4.4. 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. 12.5. 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. Timer 0 Interrupt Request TF0 TCON.5 ET0 IEN0.1 Timer 1 Interrupt Request TF1 TCON.7 ET1 IEN0.3 Figure 46. Timer Interrupt System 60 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 12.6. Registers TCON (S:88h) Timer/Counter Control Register. 7 6 5 4 3 2 1 0 TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0 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 Figure 47. TCON Register Draft.A - March 30, 2001 61 Preview - Confidential T89C51AC2 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 Bit Number Bit Mnemonic 7 GATE1 6 C/T1# 5 M11 4 M01 3 GATE0 2 C/T0# 1 M10 0 M00 Description 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. 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. Timer 1 Mode Select Bits M11 M01 Operating 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). Reloaded from TH1 at overflow. 1 1 Mode 3: Timer 1 halted. Retains count. 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. 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. Timer 0 Mode Select Bit M10 M00 Operating mode 0 0 Mode 0: 8-bit Timer/Counter (TH0) with 5-bit prescaler (TL0). 0 1 Mode 1: 16-bit Timer/Counter. 1 0 Mode 2: 8-bit auto-reload Timer/Counter (TL0). Reloaded from TH0 at overflow. 1 1 Mode 3: TL0 is an 8-bit Timer/Counter. TH0 is an 8-bit Timer using Timer 1’s TR0 and TF0 bits. Reset Value= 0000 0000b Figure 48. TMOD Register TH0 (S:8Ch) Timer 0 High Byte Register. 7 6 5 4 Bit Number Bit Mnemonic 7:0 3 2 1 0 Description High Byte of Timer 0. Reset Value= 0000 0000b Figure 49. TH0 Register 62 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 TL0 (S:8Ah) Timer 0 Low Byte Register. 7 6 5 4 3 Bit Number Bit Mnemonic 7:0 2 1 0 2 1 0 2 1 0 Description Low Byte of Timer 0. Reset Value= 0000 0000b Figure 50. TL0 Register TH1 (S:8Dh) Timer 1 High Byte Register. 7 6 5 4 3 Bit Number Bit Mnemonic 7:0 Description High Byte of Timer 1. Reset Value= 0000 0000b Figure 51. TH1 Register TL1 (S:8Bh) Timer 1 Low Byte Register. 7 6 5 4 Bit Number Bit Mnemonic 7:0 3 Description Low Byte of Timer 1. Reset Value= 0000 0000b Figure 52. TL1 Register Draft.A - March 30, 2001 63 Preview - Confidential T89C51AC2 13. Timer 2 13.1. Introduction The T89C51AC2 timer 2 is compatible with timer 2 in the 80C52. It is a 16-bit timer/counter: the count is maintained by two eight-bit timer registers, TH2 and TL2 that are cascadeconnected. It is controlled by T2CON register (See Table 55) and T2MOD register (See Table 56). Timer 2 operation is similar to Timer 0 and Timer 1. C/T2 selects FOSC/6 (timer operation) or external pin T2 (counter operation) as timer register input. Setting TR2 allows TL2 to be incremented by the selected input. Timer 2 includes the following enhancements: • Auto-reload mode (up or down counter) • Programmable clock-output 13.2. Auto-Reload Mode The auto-reload mode configures timer 2 as a 16-bit timer or event counter with automatic reload. This feature is controlled by the DCEN bit in T2MOD register (See Table 56). Setting the DCEN bit enables timer 2 to count up or down as shown in Figure 53. In this mode the T2EX pin controls the counting direction. When T2EX is high, timer 2 up-counts. Timer overflow occurs at FFFFh which sets the TF2 flag and generates an interrupt request. The overflow also causes the 16-bit value in RCAP2H and RCAP2L registers to be loaded into the timer registers TH2 and TL2. When T2EX is low, timer 2 down-counts. Timer underflow occurs when the count in the timer registers TH2 and TL2 equals the value stored in RCAP2H and RCAP2L registers. The underflow sets TF2 flag and reloads FFFFh into the timer registers. The EXF2 bit toggles when timer 2 overflow or underflow, depending on the direction of the count. EXF2 does not generate an interrupt. This bit can be used to provide 17-bit resolution. 64 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 FT2 CLOCK :6 0 1 TR2 T2CON.2 CT/2 T2CON.1 T2 (DOWN COUNTING RELOAD VALUE) FFh FFh (8-bit) (8-bit) T2EX: 1=UP 2=DOWN TOGGLE T2CONreg EXF2 TL2 TH2 (8-bit) (8-bit) RCAP2L (8-bit) TF2 TIMER 2 INTERRUPT T2CONreg RCAP2H (8-bit) (UP COUNTING RELOAD VALUE) Figure 53. Auto-Reload Mode Up/Down Counter 13.3. Programmable Clock-Output In clock-out mode, timer 2 operates as a 50%-duty-cycle, programmable clock generator (See Figure 54). The input clock increments TL2 at frequency FOSC/2. The timer repeatedly counts to overflow from a loaded value. At overflow, the contents of RCAP2H and RCAP2L registers are loaded into TH2 and TL2. In this mode, timer 2 overflows do not generate interrupts. The formula gives the clock-out frequency depending on the system oscillator frequency and the value in the RCAP2H and RCAP2L registers: F × 2 x2 osc Clock – OutFrequency = -------------------------------------------------------------------------------------4 × ( 65536 – RCAP2H ⁄ RCAP2L ) NOTE: X2 bit is located in CKCON register. In X2 mode, FOSC=FXTAL. In standard mode, FOSC=FXTAL/2. For a 16 MHz system clock, timer 2 has a programmable frequency range of 61 Hz (FOSC/216) to 4 MHz (FOSC/ 4). The generated clock signal is brought out to T2 pin (P1.0). Timer 2 is programmed for the clock-out mode as follows: • Set T2OE bit in T2MOD register. • Clear C/T2 bit in T2CON register. • Determine the 16-bit reload value from the formula and enter it in RCAP2H/RCAP2L registers. Draft.A - March 30, 2001 65 Preview - Confidential T89C51AC2 • Enter a 16-bit initial value in timer registers TH2/TL2. It can be the same as the reload value or different depending on the application. • To start the timer, set TR2 run control bit in T2CON register. It is possible to use timer 2 as a baud rate generator and a clock generator simultaneously. For this configuration, the baud rates and clock frequencies are not independent since both functions use the values in the RCAP2H and RCAP2L registers. FT2 CLOCK 0 1 TR2 T2CON.2 CT/2 TL2 (8-bit) TH2 (8-bit) T2CON.1 OVERFLOW RCAP2 RCAP2 (8-bit) (8-bit) T2 1 0 :2 C/T2 T2CON reg T2OE T2MOD reg T2EX EXF2 EXEN2 T2CON reg TIMER 2 INTERRUPT T2CON reg Figure 54. Clock-Out Mode 66 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 13.4. Registers T2CON (S:C8h) Timer 2 Control Register 7 6 5 4 3 2 1 0 TF2 EXF2 RCLK TCLK EXEN2 TR2 C/T2# CP/RL2# Bit Number Bit Mnemonic 7 TF2 Description Timer 2 overflow Flag TF2 is not set if RCLK=1 or TCLK = 1. Must be cleared by software. Set by hardware on timer 2 overflow. 6 EXF2 Timer 2 External Flag Set when a capture or a reload is caused by a negative transition on T2EX pin if EXEN2=1. Set to cause the CPU to vector to timer 2 interrupt routine when timer 2 interrupt is enabled. Must be cleared by software. 5 RCLK Receive Clock bit Clear to use timer 1 overflow as receive clock for serial port in mode 1 or 3. Set to use timer 2 overflow as receive clock for serial port in mode 1 or 3. 4 TCLK Transmit Clock bit Clear to use timer 1 overflow as transmit clock for serial port in mode 1 or 3. Set to use timer 2 overflow as transmit clock for serial port in mode 1 or 3. 3 EXEN2 Timer 2 External Enable bit Clear to ignore events on T2EX pin for timer 2 operation. Set to cause a capture or reload when a negative transition on T2EX pin is detected, if timer 2 is not used to clock the serial port. 2 TR2 1 C/T2# 0 CP/RL2# Timer 2 Run control bit Clear to turn off timer 2. Set to turn on timer 2. Timer/Counter 2 select bit Clear for timer operation (input from internal clock system: FOSC). Set for counter operation (input from T2 input pin). Timer 2 Capture/Reload bit If RCLK=1 or TCLK=1, CP/RL2# is ignored and timer is forced to auto-reload on timer 2 overflow. Clear to auto-reload on timer 2 overflows or negative transitions on T2EX pin if EXEN2=1. Set to capture on negative transitions on T2EX pin if EXEN2=1. Reset Value = 0000 0000b Bit addressable Figure 55. T2CON Register Draft.A - March 30, 2001 67 Preview - Confidential T89C51AC2 T2MOD (S:C9h) Timer 2 Mode Control Register 7 6 5 4 3 2 1 0 - - - - - - T2OE DCEN Bit Number Bit Mnemonic Description 7 - Reserved The value read from this bit is indeterminate. Do not set this bit. 6 - Reserved The value read from this bit is indeterminate. Do not set this bit. 5 - Reserved The value read from this bit is indeterminate. Do not set this bit. 4 - Reserved The value read from this bit is indeterminate. Do not set this bit. 3 - Reserved The value read from this bit is indeterminate. Do not set this bit. 2 - Reserved The value read from this bit is indeterminate. Do not set this bit. 1 T2OE Timer 2 Output Enable bit Clear to program P1.0/T2 as clock input or I/O port. Set to program P1.0/T2 as clock output. 0 DCEN Down Counter Enable bit Clear to disable timer 2 as up/down counter. Set to enable timer 2 as up/down counter. Reset Value = XXXX XX00b Not bit addressable Figure 56. T2MOD Register TH2 (S:CDh) Timer 2 High Byte Register 7 6 5 4 3 2 1 0 - - - - - - - - Bit Number Bit Mnemonic 7-0 Description High Byte of Timer 2. Reset Value = 0000 0000b Not bit addressable Figure 57. TH2 Register 68 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 TL2 (S:CCh) Timer 2 Low Byte Register 7 6 5 4 3 2 1 0 - - - - - - - - Bit Number Bit Mnemonic 7-0 Description Low Byte of Timer 2. Reset Value = 0000 0000b Not bit addressable Figure 58. TL2 Register RCAP2H (S:CBh) Timer 2 Reload/Capture High Byte Register 7 6 5 4 3 2 1 0 - - - - - - - - Bit Number Bit Mnemonic 7-0 Description High Byte of Timer 2 Reload/Capture. Reset Value = 0000 0000b Not bit addressable Figure 59. RCAP2H Register RCAP2L (S:CAh) Timer 2 Reload/Capture Low Byte Register 7 6 5 4 3 2 1 0 - - - - - - - - Bit Number Bit Mnemonic 7-0 Description Low Byte of Timer 2 Reload/Capture. Reset Value = 0000 0000b Not bit addressable Figure 60. RCAP2L Register Draft.A - March 30, 2001 69 Preview - Confidential T89C51AC2 14. WatchDog Timer 14.1. Introduction T89C51AC2 contains a powerful programmable hardware WatchDog Timer (WDT) that automatically resets the chip if it software fails to reset the WDT before the selected time interval has elapsed. It permits large Time-Out ranking from 16ms to 2s @Fosc = 12MHz. This WDT consist of a 14-bit counter plus a 7-bit programmable counter, a WatchDog Timer reset register (WDTRST) and a WatchDog Timer programming (WDTPRG) register. When exiting reset, the WDT is -by defaultdisable. To enable the WDT, the user has to write the sequence 1EH and E1H into WDTRST register. When the WatchDog Timer is enabled, it will increment every machine cycle while the oscillator is running and there is no way to disable the WDT except through reset (either hardware reset or WDT overflow reset). When WDT overflows, it will generate an output RESET pulse at the RST pin. The RESET pulse duration is 96xTOSC, where TOSC=1/ FOSC. To make the best use of the WDT, it should be serviced in those sections of code that will periodically be executed within the time required to prevent a WDT reset. Fwd CLOCK ÷ PS CPU and Peripheral Clock ÷6 Decoder RESET WR Control WDTRST Enable 14-bit COUNTER 7-bit COUNTER PERIPHERAL CLOCK Outputs - - - - - 2 1 0 RESET Figure 61. WatchDog Timer 70 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 14.2. WatchDog Programming The three lower bits (S0, S1, S2) located into WDTPRG register permits to program the WDT duration. Table 19. Machine Cycle Count S2 S1 S0 Machine Cycle Count 0 0 0 214 - 1 0 0 1 215 - 1 0 1 0 216 - 1 0 1 1 217 - 1 1 0 0 218 - 1 1 0 1 219 - 1 1 1 0 220 - 1 1 1 1 221 - 1 To compute WD Time-Out, the following formula is applied: F XTAL FTime – Out = -----------------------------------------------------------14 Svalue 12 × ( ( 2 × 2 ) – 1) Note: Svalue represents the decimal value of (S2 S1 S0) Find Hereafter computed Time-Out value for FoscXTAL = 12MHz Table 20. Time-Out Computation S2 S1 S0 Fosc=12MHz Fosc=16MHz 0 0 0 16.38 ms 12.28 ms 9.82 ms 0 0 1 32.77 ms 24.57 ms 19.66 ms 0 1 0 65.54 ms 49.14 ms 39.32 ms 0 1 1 131.07 ms 98.28 ms 78.64 ms 1 0 0 262.14 ms 196.56 ms 157.28 ms 1 0 1 524.29 ms 393.12 ms 314.56 ms 1 1 0 1.05 s 786.24 ms 629.12 ms 1 1 1 2.10 s 1.57 s 1.25 ms Draft.A - March 30, 2001 Fosc=20MHz 71 Preview - Confidential T89C51AC2 14.3. WatchDog Timer during Power down mode and Idle In Power Down mode the oscillator stops, which means the WDT also stops. While in Power Down mode the user does not need to service the WDT. There are 2 methods of exiting Power Down mode: by a hardware reset or via a level activated external interrupt which is enabled prior to entering Power Down mode. When Power Down is exited with hardware reset, servicing the WDT should occur as it normally does whenever T89C51AC2 is reset. Exiting Power Down with an interrupt is significantly different. The interrupt is held low long enough for the oscillator to stabilize. When the interrupt is brought high, the interrupt is serviced. To prevent the WDT from resetting the device while the interrupt pin is held low, the WDT is not started until the interrupt is pulled high. It is suggested that the WDT be reset during the interrupt service for the interrupt used to exit Power Down. To ensure that the WDT does not overflow within a few states of exiting of powerdown, it is best to reset the WDT just before entering powerdown. In the Idle mode, the oscillator continues to run. To prevent the WDT from resetting T89C51AC2 while in Idle mode, the user should always set up a timer that will periodically exit Idle, service the WDT, and re-enter Idle mode. 72 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 14.4. Register WDTPRG (S:A7h) WatchDog Timer Duration Programming register 7 6 5 4 3 2 1 0 - - - - - S2 S1 S0 Bit Number Bit Mnemonic Description 7 - Reserved The value read from this bit is indeterminate. Do not set this bit. 6 - Reserved The value read from this bit is indeterminate. Do not set this bit. 5 - Reserved The value read from this bit is indeterminate. Do not set this bit. 4 - Reserved The value read from this bit is indeterminate. Do not set this bit. 3 - Reserved The value read from this bit is indeterminate. Do not set this bit. 2 S2 WatchDog Timer Duration selection bit 2 Work in conjunction with bit 1 and bit 0. 1 S1 WatchDog Timer Duration selection bit 1 Work in conjunction with bit 2 and bit 0. 0 S0 WatchDog Timer Duration selection bit 0 Work in conjunction with bit 1 and bit 2. Reset Value = XXXX X000b Figure 62. WDTPRG Register WDTRST (S:A6h Write only) WatchDog Timer Enable register 7 6 5 4 3 2 1 0 - - - - - - - - Bit Number Bit Mnemonic 7 - Description Watchdog Control Value Reset Value = 1111 1111b NOTE: The WDRST register is used to reset/enable the WDT by writing 1EH then E1H in sequence. . Figure 63. WDTRST Register Draft.A - March 30, 2001 73 Preview - Confidential T89C51AC2 15. Programmable Counter Array PCA 15.1. Introduction The PCA provides more timing capabilities with less CPU intervention than the standard timer/counters. Its advantages include reduced software overhead and improved accuracy. The PCA consists of a dedicated timer/ counter which serves as the time base for an array of five compare/capture modules. Its clock input can be programmed to count any of the following signals: • • • • PCA clock frequency / 6 PCA clock frequency / 2 Timer 0 overflow External input on ECI (P1.2) Each compare/capture modules can be programmed in any one of the following modes: • • • • rising and/or trailing edge capture, software timer, high-speed output, pulse width modulator. Module 4 can also be programmed as a watchdog timer. see Section "PCA Watchdog Timer". When the compare/capture modules are programmed in capture mode, software timer, or high speed output mode, an interrupt can be generated when the module executes its function. All five modules plus the PCA timer overflow share one interrupt vector. The PCA timer/counter and compare/capture modules share Port 1 for external I/Os. These pins are listed below. If the port is not used for the PCA, it can still be used for standard I/O. PCA component External I/O Pin 16-bit Counter P1.2 / ECI 16-bit Module 0 P1.3 / CEX0 16-bit Module 1 P1.4 / CEX1 16-bit Module 2 P1.5 / CEX2 16-bit Module 3 P1.6 / CEX3 16-bit Module 4 P1.7 / CEX4 The PCA timer is a common time base for all five modules (see Figure 9). The timer count source is determined from the CPS1 and CPS0 bits in the CMOD SFR (see Table 8) and can be programmed to run at: • • • • 1/6 the PCA clock frequency. 1/2 the PCA clock frequency. the Timer 0 overflow. the input on the ECI pin (P1.2). 74 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 To PCA modules FPca/6 overflow FPca / 2 CH T0 OVF It CL 16 bit up/down counter P1.2 CIDL WDTE CF CR CPS1 CPS0 ECF CMOD 0xD9 CCF2 CCF1 CCF0 CCON 0xD8 Idle CCF4 CCF3 Figure 64. PCA Timer/Counter Draft.A - March 30, 2001 75 Preview - Confidential T89C51AC2 15.2. PCA Interrupt CF CR CCF4 CCF3 CCF2 CCF1 CCF0 CCON 0xD8 PCA Timer/Counter Module 0 Module 1 To Interrupt Module 2 Module 3 Module 4 CMOD.0 ECF ECCFn CCAPMn.0 EC EA Figure 65. PCA Timer Interrupts 76 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 15.3. PCA Capture Mode To use one of the PCA modules in capture mode either one or both of the CCAPM bits CAPN and CAPP for that module must be set. The external CEX input for the module (on port 1) is sampled for a transition. When a valid transition occurs the PCA hardware loads the value of the PCA counter registers (CH and CL) into the module’s capture registers (CCAPnL and CCAPnH). If the CCFn bit for the module in the CCON SFR and the ECCFn bit in the CCAPMn SFR are set then an interrupt will be generated. PCA Counter CH (8bits) CL (8bits) CEXn n = 0, 4 CCAPnH CCAPnL PCA Interrupt Request CCFn CCON Reg - 0CAPPnCAPNn000 ECCFn 0 7 CCAPMn Register (n = 0, 4) Figure 66. PCA Capture Mode Draft.A - March 30, 2001 77 Preview - Confidential T89C51AC2 15.4. 16-bit Software Timer Mode The PCA modules can be used as software timers by setting both the ECOM and MAT bits in the modules CCAPMn register. The PCA timer will be compared to the module’s capture registers and when a match occurs an interrupt will occur if the CCFn (CCON SFR) and the ECCFn (CCAPMn SFR) bits for the module are both set. PCA Counter CH CL Compare/Capture Module CCAPnH CCAPnL 16-Bit Comparator Match Enable Toggle CCFn CCON reg 7 “0” Reset Write to “1” CCAPnL Write to CCAPnH CEXn PCA Interrupt Request ECOMn00MATnTOGn0ECCFn 0 CCAPMn Register (n = 0, 4) For software Timer mode, set ECOMn and MATn. For high speed output mode, set ECOMn, MATn and TOGn. Figure 67. PCA 16-bit Software Timer and High Speed Output Mode 78 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 15.5. High Speed Output Mode In this mode the CEX output (on port 1) associated with the PCA module will toggle each time a match occurs between the PCA counter and the module’s capture registers. To activate this mode the TOG, MAT, and ECOM bits in the module’s CCAPMn SFR must be set. CF Write to CCAPnH CR CCF4 CCF3 CCF2 CCF1 CCF0 CCON 0xD8 Reset PCA IT Write to CCAPnL “0” CCAPnH “1” CCAPnL Enable 16 bit comparator CH Match CL CEXn PCA counter/timer ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn CCAPMn, n = 0 to 4 0xDA to 0xDE Figure 68. PCA High speed Output Mode Draft.A - March 30, 2001 79 Preview - Confidential T89C51AC2 15.6. Pulse Width Modulator Mode All the PCA modules can be used as PWM outputs. The output frequency depends on the source for the PCA timer. All the modules will have the same output frequency because they all share the PCA timer. The duty cycle of each module is independently variable using the module’s capture register CCAPLn. When the value of the PCA CL SFR is less than the value in the module’s CCAPLn SFR the output will be low, when it is equal to or greater than it, the output will be high. When CL overflows from FF to 00, CCAPLn is reloaded with the value in CCAPHn. the allows the PWM to be updated without glitches. The PWM and ECOM bits in the module’s CCAPMn register must be set to enable the PWM mode. CCAPn CL rolls over from FFh TO 00h loads CCAPnH contents into CCAPnL CCAPxL “0 CL < CCAPnL 8-Bit Comparator CL (8 bits) CEX CL >= CCAPnL “1” 7 ECOMn0 00 0 0PWMn0 CCAPMn Register Figure 69. PCA PWM Mode 80 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 15.7. PCA Watchdog Timer An on-board watchdog timer is available with the PCA to improve system reliability without increasing chip count. Watchdog timers are useful for systems that are sensitive to noise, power glitches, or electrostatic discharge. Module 4 is the only PCA module that can be programmed as a watchdog. However, this module can still be used for other modes if the watchdog is not needed. The user pre-loads a 16-bit value in the compare registers. Just like the other compare modes, this 16-bit value is compared to the PCA timer value. If a match is allowed to occur, an internal reset will be generated. This will not cause the RST pin to be driven high. To hold off the reset, the user has three options: • 1. periodically change the compare value so it will never match the PCA timer, • 2. periodically change the PCA timer value so it will never match the compare values, or • 3. disable the watchdog by clearing the WDTE bit before a match occurs and then re-enable it. The first two options are more reliable because the watchdog timer is never disabled as in option #3. If the program counter ever goes astray, a match will eventually occur and cause an internal reset. If other PCA modules are being used the second option not recommended either. Remember, the PCA timer is the time base for all modules; changing the time base for other modules would not be a good idea. Thus, in most applications the first solution is the best option. Draft.A - March 30, 2001 81 Preview - Confidential T89C51AC2 15.8. PCA Registers CMOD (S:D8h) PCA Counter Mode Register 7 6 5 4 3 2 1 0 CIDL WDTE - - - CPS1 CPS0 ECF Bit Number Bit Mnemonic Description 7 CIDL PCA Counter Idle Control bit Clear to let the PCA run during Idle mode. Set to stop the PCA when Idle mode is invoked. 6 WDTE Watchdog Timer Enable Clear to disable Watchdog Timer function on PCA Module 4, Set to enable it. 5 - Reserved The value read from this bit is indeterminate. Do not set this bit. 4 - Reserved The value read from this bit is indeterminate. Do not set this bit. 3 - Reserved The value read from this bit is indeterminate. Do not set this bit. 2 CPS1 1 CPS0 0 ECF EWC Count Pulse CPS1 CPS0 0 0 0 1 1 0 1 1 Select bits Clock source Internal Clock, FPca/6 Internal Clock, FPca/2 Timer 0 overflow External clock at ECI/P1.2 pin (Max. Rate = FPca/4) Enable PCA Counter Overflow Interrupt bit Clear to disable CF bit in CCON register to generate an interrupt. Set to enable CF bit in CCON register to generate an interrupt. Reset Value = 00XX X000b Figure 70. CMOD Register 82 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 CCON (S:D8h) PCA Counter Control Register 7 6 5 4 3 2 1 0 CF CR - CCF4 CCF3 CCF2 CCF1 CCF0 Bit Number Bit Mnemonic Description 7 CF PCA Timer/Counter Overflow flag Set by hardware when the PCA Timer/Counter rolls over. This generates a PCA interrupt request if the ECF bit in CMOD register is set. Must be cleared by software. 6 CR PCA Timer/Counter Run Control bit Clear to turn the PCA Timer/Counter off. Set to turn the PCA Timer/Counter on. 5 - 4 3 2 1 0 Reserved The value read from this bit is indeterminate. Do not set this bit. CCF4 PCA Module 4 Compare/Capture flag Set by hardware when a match or capture occurs. This generates a PCA interrupt request if the ECCF 4 bit in CCAPM 4 register is set. Must be cleared by software. CCF3 PCA Module 3 Compare/Capture flag Set by hardware when a match or capture occurs. This generates a PCA interrupt request if the ECCF 3 bit in CCAPM 3 register is set. Must be cleared by software. CCF2 PCA Module 2 Compare/Capture flag Set by hardware when a match or capture occurs. This generates a PCA interrupt request if the ECCF 2 bit in CCAPM 2 register is set. Must be cleared by software. CCF1 PCA Module 1 Compare/Capture flag Set by hardware when a match or capture occurs. This generates a PCA interrupt request if the ECCF 1 bit in CCAPM 1 register is set. Must be cleared by software. CCF0 PCA Module 0 Compare/Capture flag Set by hardware when a match or capture occurs. This generates a PCA interrupt request if the ECCF 0 bit in CCAPM 0 register is set. Must be cleared by software. Reset Value = 00X0 0000b Figure 71. CCON Register Draft.A - March 30, 2001 83 Preview - Confidential T89C51AC2 CCAP0H (S:FAh) CCAP1H (S:FBh ) CCAP2H (S:FCh) CCAP3H (S:FDh) CCAP4H (S:FEh) PCA High Byte Compare/Capture Module n Register (n=0..4) 7 6 5 4 3 2 1 0 CCAPnH 7 CCAPnH 6 CCAPnH 5 CCAPnH 4 CCAPnH 3 CCAPnH 2 CCAPnH 1 CCAPnH 0 Bit Number Bit Mnemonic 7:0 CCAPnH 7:0 Description High byte of EWC-PCA comparison or capture values Reset Value = 0000 0000b Figure 72. CCAPnH Registers CCAP0L (S: EAh) CCAP1L (S:EBh ) CCAP2L (S:ECh) CCAP3L (S:EDh) CCAP4L (S:EEh) PCA Low Byte Compare/Capture Module n Register (n=0..4) 7 6 5 4 3 2 1 0 CCAPnL 7 CCAPnL 6 CCAPnL 5 CCAPnL 4 CCAPnL 3 CCAPnL 2 CCAPnL 1 CCAPnL 0 Bit Number Bit Mnemonic 7:0 CCAPnL 7:0 Description Low byte of EWC-PCA comparison or capture values Reset Value = 0000 0000b Figure 73. CCAPnL Registers 84 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 CCAPM0 (S:DAh) CCAPM1 (S:DBh) CCAPM2 (S:DCh) CCAPM3 (S:DDh) CCAPM4 (S:DEh) PCA Compare/Capture Module n Mode registers (n=0..4) 7 6 5 4 3 2 1 0 - ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn Bit Number Bit Mnemonic 7 - Description Reserved The Value read from this bit is indeterminate. Do not set this bit. 6 ECOMn Enable Compare Mode Module x bit Clear to disable the Compare function. Set to enable the Compare function. The Compare function is used to implement the software Timer, the high-speed output, the Pulse Width Modulator (PWM) and the Watchdog Timer (WDT). 5 CAPPn Capture Mode (Positive) Module x bit Clear to disable the Capture function triggered by a positive edge on CEXx pin. Set to enable the Capture function triggered by a positive edge on CEXx pin 4 CAPNn Capture Mode (Negative) Module x bit Clear to disable the Capture function triggered by a negative edge on CEXx pin. Set to enable the Capture function triggered by a negative edge on CEXx pin. MATn Match Module x bit Set when a match of the PCA Counter with the Compare/Capture register sets CCFx bit in CCON register, flagging an interrupt. Must be cleared by software. 2 TOGn Toggle Module x bit The toggle mode is configured by setting ECOMx, MATx and TOGx bits. Set when a match of the PCA Counter with the Compare/Capture register toggles the CEXx pin. Must be cleared by software. 1 PWMn Pulse Width Modulation Module x Mode bit Set to configure the module x as an 8-bit Pulse Width Modulator with output waveform on CEXx pin. Must be cleared by software. 0 ECCFn Enable CCFx Interrupt bit Clear to disable CCFx bit in CCON register to generate an interrupt request. Set to enable CCFx bit in CCON register to generate an interrupt request. 3 Reset Value = X000 0000b Figure 74. CCAPMn Registers Draft.A - March 30, 2001 85 Preview - Confidential T89C51AC2 CH (S:F9h) PCA Counter Register High value 7 6 5 4 3 2 1 0 CH 7 CH 6 CH 5 CH 4 CH 3 CH 2 CH 1 CH 0 Bit Number Bit Mnemonic 7:0 CH 7:0 Description High byte of Timer/Counter Reset Value = 0000 00000b Figure 75. CH Register CL (S:E9h) PCA counter Register Low value 7 6 5 4 3 2 1 0 CL 7 CL 6 CL 5 CL 4 CL 3 CL 2 CL 1 CL 0 Bit Number Bit Mnemonic 7:0 CL0 7:0 Description Low byte of Timer/Counter Reset Value = 0000 00000b Figure 76. CL Register 86 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 16. Analog-to-Digital Converter (ADC) 16.1. Introduction This section describes the on-chip 10 bit analog-to-digital converter of the T89C51AC2. Eight ADC channels are available for sampling of the external sources AN0 to AN7. An analog multiplexer allows the single ADC converter to select one from the 8 ADC channels as ADC input voltage (ADCIN). ADCIN is converted by the 10 bitcascaded potentiometric ADC. Two kind of conversion are available: - Standard conversion (8 bits). - Precision conversion (10 bits). For the precision conversion, set bit PSIDLE in ADCON register and start conversion. The chip is in a pseudoidle mode, the CPU doesn’t run but the peripherals are always running. This mode allows digital noise to be as low as possible, to ensure high precision conversion. For this mode it is necessary to work with end of conversion interrupt, which is the only way to wake up the chip. If another interrupt occurs during the precision conversion, it will be treated only after this conversion is ended. 16.2. Features • 8 channels with multiplexed inputs • 10-bit cascaded potentiometric ADC • Conversion time 20 micro-seconds • Zero Error (offset) +/- 2 LSB max • Positive Reference Voltage Range 2.4 to 3.0Volt • ADCIN Range 0 to 3Volt • Integral non-linearity typical 1 LSB, max. 2 LSB • Differential non-linearity typical 0.5 LSB, max. 1 LSB • Conversion Complete Flag or Conversion Complete Interrupt • Selected ADC Clock 16.3. ADC Port1 I/O Functions Port 1 pins are general I/O that are shared with the ADC channels. The channel select bit in ADCF register define which ADC channel/port1 pin will be used as ADCIN. The remaining ADC channels/port1 pins can be used as general purpose I/O or as the alternate function that is available. Writes to the port register which aren’t selected by the ADCF will not have any effect. Draft.A - March 30, 2001 87 Preview - Confidential T89C51AC2 ADCON.5 ADCON.3 ADEN ADSST ADC Interrupt Request ADCON.4 ADEOC ADC CLOCK CONTROL EADC AN0/P1.0 000 AN1/P1.1 001 AN2/P1.2 010 AN3/P1.3 011 AN4/P1.4 100 AN5/P1.5 101 AN6/P1.6 110 AN7/P1.7 111 IEN1.1 ADCIN 8 ADDH 2 ADDL + SAR - AVSS Sample and Hold 10 R/2R DAC SCH2 SCH1 SCH0 ADCON.2 ADCON.1 ADCON.0 VAREF VAGND Figure 77. ADC Description Figure 78 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” of the T89C51AC2 datasheet. CLK ADEN TSETUP ADSST TCONV ADEOC Figure 78. Timing Diagram NOTE: Tsetup = 4 us Tconv=11 clock ADC 88 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 16.4. ADC Converter Operation A start of single A/D conversion is triggered by setting bit ADSST (ADCON.3). The busy flag ADSST(ADCON.3) is automatically set when an A/D conversion is running. After completion of the A/D conversion, it is cleared by hardware. This flag can be read only, a write has no effect. The end-of-conversion flag ADEOC (ADCON.4) is set when the value of conversion is available in ADDH and ADDL, it is cleared by software. If the bit EADC (IEN1.1) is set, an interrupt occur when flag ADEOC is set (see Figure 80). Clear this flag for re-arming the interrupt. The bits SCH0 to SCH2 in ADCON register are used for the analog input channel selection. Before Starting Power reduction modes the ADC conversion has to be completed. Table 21. Selected Analog input SCH2 SCH1 SCH0 Selected Analog input 0 0 0 AN0 0 0 1 AN1 0 1 0 AN2 0 1 1 AN3 1 0 0 AN4 1 0 1 AN5 1 1 0 AN6 1 1 1 AN7 16.5. Voltage Conversion When the ADCIN is equals to VAREF the ADC converts the signal to 3FFh (full scale). If the input voltage equals VAGND, the ADC converts it to 000h. Input voltage between VAREF and VAGND are a straight-line linear conversion. All other voltages will result in 3FFh if greater than VAREF and 000h if less than VAGND. Note that ADCIN should not exceed VAREF absolute maximum range! Draft.A - March 30, 2001 89 Preview - Confidential T89C51AC2 16.6. Clock Selection The maximum clock frequency for ADC is 700KHz. A prescaler is featured (ADCCLK) to generate the ADC clock from the oscillator frequency. conversion clock fADC CPU CLOCK ÷2 Prescaler ADCLK CPU Core Clock Symbol A/D Converter Figure 79. A/D Converter clock 16.7. ADC Standby Mode When the ADC is not used, it is possible to set it in standby mode by clearing bit ADEN in ADCON register. In this mode the power dissipation is about 1uW. 90 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 16.8. IT ADC management An interrupt end-of-conversion will occurs when the bit ADEOC is actived and the bit EADC is set. For re-arming the interrupt the bit ADEOC must be cleared by software. ADCI ADEOC ADCON.2 EADC IEN1.1 Figure 80. ADC interrupt structure Draft.A - March 30, 2001 91 Preview - Confidential T89C51AC2 16.9. Registers ADCF (S:F6h) ADC Configuration 7 6 5 4 3 2 1 0 CH 7 CH 6 CH 5 CH 4 CH 3 CH 2 CH 1 CH 0 Bit Number Bit Mnemonic 7-0 CH 0:7 Description Channel Configuration Set to use P1.x as ADC input. Clear tu use P1.x as standart I/O port. Reset Value=0000 0000b Figure 81. ADCF Register ADCON (S:F3h) ADC Control Register 7 6 5 4 3 2 1 0 - PSIDLE ADEN ADEOC ADSST SCH2 SCH1 SCH0 Bit Number Bit Mnemonic Description 7 - 6 PSIDLE 5 ADEN 4 ADEOC End Of Conversion 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 Set to start an A/D conversion. Cleared by hardware after completion of the conversion 2-0 SCH2:0 Selection of channel to convert see Table 21 Pseudo Idle mode (best precision) Set to put in idle mode during conversion Clear to converte without idle mode. Enable/Standby Mode Set to enable ADC Clear for Standby mode (power dissipation 1 uW). Reset Value=X000 0000b Figure 82. ADCON Register 92 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 ADCLK (S:F2h) ADC Clock Prescaler 7 6 5 4 3 2 1 0 - - - PRS 4 PRS 3 PRS 2 PRS 1 PRS 0 Bit Number Bit Mnemonic 7-5 - 4-0 PRS4:0 Description Reserved The value read from these bits are indeterminate. Do not set these bits. Clock Prescaler fADC = fosc / (4 (or 2 in X2 mode)* PRS) Reset Value: XXX0 0000b Figure 83. ADCLK Register ADDH (S:F5h Read Only) ADC Data High byte register 7 6 5 4 3 2 1 0 ADAT 9 ADAT 8 ADAT 7 ADAT 6 ADAT 5 ADAT 4 ADAT 3 ADAT 2 Bit Number Bit Mnemonic 7-0 ADAT9:2 Description ADC result bits 9-2 Reset Value: 00h Figure 84. ADDH Register ADDL (S:F4h Read Only) ADC Data Low byte register 7 6 5 4 3 2 1 0 - - - - - - ADAT 1 ADAT 0 Bit Number Bit Mnemonic 7-2 - 1-0 ADAT1:0 Description Reserved The value read from these bits are indeterminate. Do not set these bits. ADC result bits 1-0 Reset Value: 00h Figure 85. ADDL Register Draft.A - March 30, 2001 93 Preview - Confidential T89C51AC2 17. Interrupt System 17.1. Introduction The CAN Controller has a total of 8 interrupt vectors: two external interrupts (INT0 and INT1), three timer interrupts (timers 0, 1 and 2), a serial port interrupt, a PCA and an ADC. These interrupts are shown below. 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 CEX0:5 00 01 10 11 IEN0.3 PCA EC TxD 00 01 10 11 IEN0.6 UART RxD ES IEN0.4 00 01 10 11 Timer 2 ET2 IEN0.5 AIN1:0 00 01 10 11 A to D Converter EADC IEN1.1 EA IPH/L IEN0.7 Interrupt Enable Priority Enable Lowest Priority Interrupts Figure 86. Interrupt Control System 94 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 Each of the interrupt sources can be individually enabled or disabled by setting or clearing a bit in the Interrupt Enable register. This register also contains a global disable bit which must be cleared to disable all the interrupts at the same time. Each interrupt source can also be individually programmed to one of four priority levels by setting or clearing a bit in the Interrupt Priority registers. The Table below shows the bit values and priority levels associated with each combination. Table 22. Priority Level Bit Values IPH.x IPL.x Interrupt Level Priority 0 0 0 (Lowest) 0 1 1 1 0 2 1 1 3 (Highest) A low-priority interrupt can be interrupted by a high priority interrupt but not by another low-priority interrupt. A high-priority interrupt cannot be interrupted by any other interrupt source. If two interrupt requests of different priority levels are received simultaneously, the request of the higher priority level is serviced. If interrupt requests of the same priority level are received simultaneously, an internal polling sequence determines which request is serviced. Thus within each priority level there is a second priority structure determined by the polling sequence, see Table 23. Table 23. Interrupt priority Within level Interrupt Name Interrupt Address Vector Priority Number external interrupt (INT0) 0003h 1 Timer0 (TF0) 000Bh 2 external interrupt (INT1) 0013h 3 Timer1 (TF1) 001Bh 4 PCA (CF or CCFn) 0033h 5 UART (RI or TI) 0023h 6 Timer2 (TF2) 002Bh 7 - - - ADC (ADCI) 0043h 8 Draft.A - March 30, 2001 95 Preview - Confidential T89C51AC2 17.2. Registers IEN0 (S:A8h) Interrupt Enable Register 7 6 5 4 3 2 1 0 EA EC ET2 ES ET1 EX1 ET0 EX0 Bit Number Bit Mnemonic Description 7 EA Enable All interrupt bit Clear to disable all interrupts. Set to enable all interrupts. If EA=1, each interrupt source is individually enabled or disabled by setting or clearing its interrupt enable bit. 6 EC PCA Interrupt Enable Clear to disable the PCA interrupt. Set to enable the PCA interrupt. 5 ET2 Timer 2 overflow interrupt Enable bit Clear to disable timer 2 overflow interrupt. Set to enable timer 2 overflow interrupt. 4 ES Serial port Enable bit Clear to disable serial port interrupt. Set to enable serial port interrupt. 3 ET1 Timer 1 overflow interrupt Enable bit Clear to disable timer 1 overflow interrupt. Set to enable timer 1 overflow interrupt. 2 EX1 External interrupt 1 Enable bit Clear to disable external interrupt 1. Set to enable external interrupt 1. 1 ET0 Timer 0 overflow interrupt Enable bit Clear to disable timer 0 overflow interrupt. Set to enable timer 0 overflow interrupt. 0 EX0 External interrupt 0 Enable bit Clear to disable external interrupt 0. Set to enable external interrupt 0. Reset Value: 0000 0000b bit addressable Figure 87. IEN0 Register 96 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 IEN1 (S:E8h) Interrupt Enable Register 7 6 5 4 - - - - Bit Number Bit Mnemonic 3 2 1 0 - EADC - Description 7 - Reserved The value read from this bit is indeterminate. Do not set this bit. 6 - Reserved The value read from this bit is indeterminate. Do not set this bit. 5 - Reserved The value read from this bit is indeterminate. Do not set this bit. 4 - Reserved The value read from this bit is indeterminate. Do not set this bit. 3 - Reserved The value read from this bit is indeterminate. Do not set this bit. 2 - Reserved The value read from this bit is indeterminate. Do not set this bit. 1 EADC 0 - ADC Interrupt Enable bit Clear to disable the ADC interrupt. Set to enable the ADC interrupt. Reserved The value read from this bit is indeterminate. Do not set this bit. Reset Value: xxxx xx0xb bit addressable Figure 88. IEN1 Register Draft.A - March 30, 2001 97 Preview - Confidential T89C51AC2 IPL0 (S:B8h) Interrupt Enable Register 7 6 5 4 3 2 1 0 - PPC PT2 PS PT1 PX1 PT0 PX0 Bit Number Bit Mnemonic Description Reserved The value read from this bit is indeterminate. Do not set this bit. 7 - 6 PPC EWC Counter Interrupt Priority bit Refer to PPCH for priority level 5 PT2 Timer 2 overflow interrupt Priority bit Refer to PT2H for priority level. 4 PS Serial port Priority bit Refer to PSH for priority level. 3 PT1 Timer 1 overflow interrupt Priority bit Refer to PT1H for priority level. 2 PX1 External interrupt 1 Priority bit Refer to PX1H for priority level. 1 PT0 Timer 0 overflow interrupt Priority bit Refer to PT0H for priority level. 0 PX0 External interrupt 0 Priority bit Refer to PX0H for priority level. Reset Value: x000 0000b bit addressable Figure 89. IPL0 Register 98 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 IPL1 (S:F8h) Interrupt Priority Low Register 1 7 6 5 4 3 2 1 0 - - - - - - PADCL - Bit Number Bit Mnemonic Description 7 - Reserved The value read from this bit is indeterminate. Do not set this bit. 6 - Reserved The value read from this bit is indeterminate. Do not set this bit. 5 - Reserved The value read from this bit is indeterminate. Do not set this bit. 4 - Reserved The value read from this bit is indeterminate. Do not set this bit. 3 - Reserved The value read from this bit is indeterminate. Do not set this bit. 2 - Reserved The value read from this bit is indeterminate. Do not set this bit. 1 PADCL 0 - ADC Interrupt Priority level less significant bit. Refer to PSPIH for priority level. Reserved The value read from this bit is indeterminate. Do not set this bit. Reset Value: xxxx xx0xb bit addressable Figure 90. IPL1 Register Draft.A - March 30, 2001 99 Preview - Confidential T89C51AC2 IPH0 (B7h) Interrupt High Priority Register 7 6 5 4 3 2 1 0 - PPCH PT2H PSH PT1H PX1H PT0H PX0H Bit Number Bit Mnemonic 7 6 5 4 3 2 1 0 - Description Reserved The value read from this bit is indeterminate. Do not set this bit. PPCH EWC-PCA Counter Interrupt Priority level most significant bit PPCH PPC Priority level 0 0 Lowest 0 1 1 0 1 1 Highest priority PT2H Timer 2 overflow interrupt High Priority bit PT2H PT2 Priority Level 0 0 Lowest 0 1 1 0 1 1 Highest PSH Serial port High Priority bit PSH PS Priority Level 0 0 Lowest 0 1 1 0 1 1 Highest PT1H Timer 1 overflow interrupt High Priority bit PT1H PT1 Priority Level 0 0 Lowest 0 1 1 0 1 1 Highest PX1H External interrupt 1 PX1H 0 0 1 1 PT0H Timer 0 overflow interrupt High Priority bit PT0H PT0 Priority Level 0 0 Lowest 0 1 1 0 1 1 Highest PX0H External interrupt 0 PX0H 0 0 1 1 High Priority bit PX1 Priority Level 0 Lowest 1 0 1 Highest high priority bit PX0 Priority Level 0 Lowest 1 0 1 Highest Reset Value: X000 0000b Figure 91. IPL0 Register 100 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 IPH1 (S:FFh) Interrupt high priority Register 1 7 6 5 4 3 2 1 0 - - - - - - PADCH - Bit Number Bit Mnemonic Description 7 - Reserved The value read from this bit is indeterminate. Do not set this bit. 6 - Reserved The value read from this bit is indeterminate. Do not set this bit. 5 - Reserved The value read from this bit is indeterminate. Do not set this bit. 4 - Reserved The value read from this bit is indeterminate. Do not set this bit. 3 - Reserved The value read from this bit is indeterminate. Do not set this bit. 2 - Reserved The value read from this bit is indeterminate. Do not set this bit. 1 PADCH 0 - ADC Interrupt Priority level most significant bit PADCH PADCL Priority level 0 0 Lowest 0 1 1 0 1 1 Highest Reserved The value read from this bit is indeterminate. Do not set this bit. Reset Value = xxxx xx0xb Figure 92. IPH1 Register Draft.A - March 30, 2001 101 Preview - Confidential T89C51AC2 18. Electrical Characteristics 18.1. Absolute Maximum Ratings (1) Ambiant Temperature Under Bias: I = industrial -40°C to 85°C Storage Temperature -65°C to + 150°C Voltage on VCC to VSS-0.5 V to + 6V Voltage on Any Pin to VSS-0.5 V to VCC + 0.2 V Power Dissipation 1 W(2) NOTES 1. Stresses at or above those listed under “ Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions may affect device reliability. 2. This value is based on the maximum allowable die temperature and the thermal resistance of the package. 102 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 18.2. DC Parameters for Standard Voltage TA = -40°C to +85°C; VSS = 0 V; VCC = 5 V ± 10%; F = 0 to 40 MHz. Symbol Parameter Min VIL Input Low Voltage VIH Input High Voltage except XTAL1, RST VIH1 Input High Voltage, XTAL1, RST VOL Output Low Voltage, ports 1, 2, 3 and 4(6) VOL1 VOH Typ Max Unit -0.5 0.7(7) V 0.2 VCC + 0.9 VCC + 0.5 V 0.7 VCC VCC + 0.5 V 0.3 0.45 1.0 V V V IOL = 100 µA(4) 0.3 0.45 1.0 V V V IOL = 200 µA(4) V V V IOH = -10 µA Output Low Voltage, port 0, ALE, PSEN (6) Output High Voltage, ports 1, 2, 3, 4 and 5 VCC - 0.3 VCC - 0.7 VCC - 1.5 VOH1 Output High Voltage, port 0, ALE, PSEN VCC - 0.3 V V V VCC - 1.5 RST Pulldown Resistor 20 IOL = 1.6 mA(4) IOL = 3.5 mA(4) IOL = 3.2 mA(4) IOL = 7.0 mA(4) IOH = -30 µA IOH = -60 µA VCC = 5 V ± 10% VCC - 0.7 RRST Test Conditions IOH = -200 µA IOH = -3.2 mA IOH = -7.0 mA VCC = 5 V ± 10% 40 (5) 200 kΩ IIL Logical 0 Input Current ports 1, 2, 3 and 4 -50 µA Vin = 0.45 V ILI Input Leakage Current ±10 µA 0.45 V < Vin < VCC ITL Logical 1 to 0 Transition Current, ports 1, 2, 3 and 4 -650 µA Vin = 2.0 V CIO Capacitance of I/O Buffer 10 pF Fc = 1 MHz TA = 25°C IPD Power Down Current 350 µA 4.5 V < VCC < 5.5 V(3) ICC Power Supply Current (Typical) ICCOP = 0.5 Freq (MHz) + 3 mA 120 ICCIDLE = 0.3 Freq (MHz) + 2 mA Table 24. DC Parameters in Standard Voltage NOTES 1. Operating ICC is measured with all output pins disconnected; XTAL1 driven with TCLCH, TCHCL = 5 ns (see Figure 96.), VIL = VSS + 0.5 V, VIH = VCC - 0.5V; XTAL2 N.C.; EA = RST = Port 0 = VCC. ICC would be slightly higher if a crystal oscillator used (see Figure 93.). 2. Idle ICC is measured with all output pins disconnected; XTAL1 driven with TCLCH, TCHCL = 5 ns, VIL = VSS + 0.5 V, VIH = VCC - 0.5 V; XTAL2 N.C; Port 0 = VCC; EA = RST = VSS (see Figure 94.). 3. Power Down ICC is measured with all output pins disconnected; EA = VSS, PORT 0 = VCC; XTAL2 NC.; RST = VSS (see Figure 95.). In addition, the WDT must be inactive and the POF flag must be set. Draft.A - March 30, 2001 103 Preview - Confidential T89C51AC2 4. Capacitance loading on Ports 0 and 2 may cause spurious noise pulses to be superimposed on the VOLs of ALE and Ports 1 and 3. The noise is due to external bus capacitance discharging into the Port 0 and Port 2 pins when these pins make 1 to 0 transitions during bus operation. In the worst cases (capacitive loading 100pF), the noise pulse on the ALE line may exceed 0.45V with maxi VOL peak 0.6V. A Schmitt Trigger use is not necessary. 5. Typicals are based on a limited number of samples and are not guaranteed. The values listed are at room temperature.. 6. Under steady state (non-transient) conditions, IOL must be externally limited as follows: Maximum IOL per port pin: 10 mA Maximum IOL per 8-bit port: Port 0: 26 mA Ports 1, 2 and 3: 15 mA Maximum total IOL for all output pins: 71 mA If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater than the listed test conditions. 7. Lower than standart C51 product independant from Vcc supply. VCC ICC VCC P0 VCC RST (NC) CLOCK SIGNAL VCC EA XTAL2 XTAL1 VSS All other pins are disconnected. Figure 93. ICC Test Condition, Active Mode VCC ICC VCC VCC P0 RST (NC) CLOCK SIGNAL EA XTAL2 XTAL1 VSS All other pins are disconnected. Figure 94. ICC Test Condition, Idle Mode 104 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 VCC ICC VCC VCC P0 RST (NC) EA XTAL2 XTAL1 VSS All other pins are disconnected. Figure 95. ICC Test Condition, Power-Down Mode VCC-0.5V 0.45V TCLCH TCHCL TCLCH = TCHCL = 5ns. 0.7VCC 0.2VCC-0.1 Figure 96. Clock Signal Waveform for ICC Tests in Active and Idle Modes 18.3. DC Parameters for A/D Converter Table 25. DC Parameters for AD Converter Symbol Parameter Min AVin Analog input voltage Rref Resistance between Vref and Vss Reference voltage Analog input Capacitance Integral non linearity Differential non linearity Offset error Vref Cai INL DNL OE Typ Vss- 0.2 12 2.40 Max Unit Vref + 0.2 V 18 60 1 0.5 -2 Draft.A - March 30, 2001 24 3.00 2 1 2 Test Conditions KOhm V pF During sampling lsb lsb lsb 105 Preview - Confidential T89C51AC2 18.4. AC Parameters 18.4.1. Explanation of the AC Symbols Each timing symbol has 5 characters. The first character is always a “T” (stands for time). The other characters, depending on their positions, stand for the name of a signal or the logical status of that signal. The following is a list of all the characters and what they stand for. Example:TAVLL = Time for Address Valid to ALE Low. TLLPL = Time for ALE Low to PSEN Low. TA = -40°C to +85°C; VSS = 0 V; VCC = 5 V ±10% ; F = 0 to 40 MHz. TA = -40°C to +85°C; VSS = 0 V; VCC = 5 V ± 10%. (Load Capacitance for port 0, ALE and PSEN = 60 pF; Load Capacitance for all other outputs = 60 pF.) Table 26, Table 29 and Table 32 give the description of each AC symbols. Table 27, Table 30 and Table 33 give for each range the AC parameter. Table 28, Table 31 and Table 34 give the frequency derating formula of the AC parameter for each speed range description. To calculate each AC symbols. take the x value and use this value in the formula. Example: TLLIV and 20 MHz, Standard clock. x = 30 ns T = 50 ns TCCIV = 4T - x = 170 ns 106 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 18.4.2. External Program Memory Characteristics Table 26. Symbol Description Symbol T Parameter Oscillator clock period TLHLL ALE pulse width TAVLL Address Valid to ALE TLLAX Address Hold After ALE TLLIV ALE to Valid Instruction In TLLPL ALE to PSEN TPLPH PSEN Pulse Width TPLIV PSEN to Valid Instruction In TPXIX Input Instruction Hold After PSEN TPXIZ Input Instruction FloatAfter PSEN TAVIV Address to Valid Instruction In TPLAZ PSEN Low to Address Float Table 27. AC Parameters for a Fix Clock (F= 40 MHz) Symbol Units Min Max T 25 ns TLHLL 40 ns TAVLL 10 ns TLLAX 10 ns TLLIV 70 ns TLLPL 15 ns TPLPH 55 ns TPLIV TPXIX 35 0 ns ns TPXIZ 18 ns TAVIV 85 ns TPLAZ 10 ns Draft.A - March 30, 2001 107 Preview - Confidential T89C51AC2 Table 28. AC Parameters for a Variable Clock Symbol Type Standard Clock X2 Clock X parameter Units TLHLL Min 2T-x T-x 10 ns TAVLL Min T-x 0.5 T - x 15 ns TLLAX Min T-x 0.5 T - x 15 ns TLLIV Max 4T-x 2T-x 30 ns TLLPL Min T-x 0.5 T - x 10 ns TPLPH Min 3T-x 1.5 T - x 20 ns TPLIV Max 3T-x 1.5 T - x 40 ns TPXIX Min x x 0 ns TPXIZ Max T-x 0.5 T - x 7 ns TAVIV Max 5T-x 2.5 T - x 40 ns TPLAZ Max x x 10 ns 18.4.3. External Program Memory Read Cycle 12 TCLCL TLHLL TLLIV ALE TLLPL TPLPH PSEN TLLAX TAVLL PORT 0 INSTR IN TPLIV TPLAZ A0-A7 TPXAV TPXIZ TPXIX INSTR IN A0-A7 INSTR IN TAVIV PORT 2 ADDRESS OR SFR-P2 ADDRESS A8-A15 108 ADDRESS A8-A15 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 18.4.4. External Data Memory Characteristics Table 29. Symbol Description Symbol Parameter TRLRH RD Pulse Width TWLWH WR Pulse Width TRLDV RD to Valid Data In TRHDX Data Hold After RD TRHDZ Data Float After RD TLLDV ALE to Valid Data In TAVDV Address to Valid Data In TLLWL ALE to WR or RD TAVWL Address to WR or RD TQVWX Data Valid to WR Transition TQVWH Data set-up to WR High TWHQX Data Hold After WR TRLAZ RD Low to Address Float TWHLH RD or WR High to ALE high Draft.A - March 30, 2001 109 Preview - Confidential T89C51AC2 Table 30. AC Parameters for a Fix Clock (F= 40 MHz) Symbol Units Min Max TRLRH 130 ns TWLWH 130 ns TRLDV TRHDX 100 0 ns ns TRHDZ 30 ns TLLDV 160 ns TAVDV 165 ns 100 ns TLLWL 50 TAVWL 75 ns TQVWX 10 ns TQVWH 160 ns TWHQX 15 ns TRLAZ TWHLH 10 0 ns 40 ns 110 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 Table 31. AC Parameters for a Variable Clock Symbol Type Standard Clock X2 Clock X parameter Units TRLRH Min 6T-x 3T-x 20 ns TWLWH Min 6T-x 3T-x 20 ns TRLDV Max 5T-x 2.5 T - x 25 ns TRHDX Min x x 0 ns TRHDZ Max 2T-x T-x 20 ns TLLDV Max 8T-x 4T -x 40 ns TAVDV Max 9T-x 4.5 T - x 60 ns TLLWL Min 3T-x 1.5 T - x 25 ns TLLWL Max 3T+x 1.5 T + x 25 ns TAVWL Min 4T-x 2T-x 25 ns TQVWX Min T-x 0.5 T - x 15 ns TQVWH Min 7T-x 3.5 T - x 15 ns TWHQX Min T-x 0.5 T - x 10 ns TRLAZ Max x x 0 ns TWHLH Min T-x 0.5 T - x 15 ns TWHLH Max T+x 0.5 T + x 15 ns 18.4.5. External Data Memory Write Cycle TWHLH ALE PSEN TLLWL TWLWH WR TLLAX PORT 0 TQVWX TQVWH A0-A7 TWHQX DATA OUT TAVWL PORT 2 ADDRESS OR SFR-P2 ADDRESS A8-A15 OR SFR P2 Draft.A - March 30, 2001 111 Preview - Confidential T89C51AC2 18.4.6. External Data Memory Read Cycle TWHLH TLLDV ALE PSEN TLLWL TRLRH RD TRHDZ TAVDV TLLAX PORT 0 DATA IN TAVWL PORT 2 TRHDX A0-A7 ADDRESS OR SFR-P2 TRLAZ ADDRESS A8-A15 OR SFR P2 18.4.7. Serial Port Timing - Shift Register Mode Table 32. Symbol Description (F= 40 MHz) Symbol Parameter TXLXL Serial port clock cycle time TQVHX Output data set-up to clock rising edge TXHQX Output data hold after clock rising edge TXHDX Input data hold after clock rising edge TXHDV Clock rising edge to input data valid Table 33. AC Parameters for a Fix Clock (F= 40 MHz) Units Symbol Min Max TXLXL 300 ns TQVHX 200 ns TXHQX 30 ns TXHDX 0 ns TXHDV 117 112 ns Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 Table 34. AC Parameters for a Variable Clock Units Symbol Type Standard Clock X2 Clock X parameter for -M range TXLXL Min 12 T 6T TQVHX Min 10 T - x 5T-x 50 ns TXHQX Min 2T-x T-x 20 ns TXHDX Min x x 0 ns TXHDV Max 10 T - x 5 T- x 133 ns ns 18.4.8. Shift Register Timing Waveforms 0 INSTRUCTION 1 2 3 4 5 6 7 8 ALE TXLXL CLOCK TXHQX TQVXH OUTPUT DATA 0 WRITE to SBUF TXHDV INPUT DATA 1 2 3 4 5 6 7 TXHDX VALID VALID VALID SET TI VALID VALID VALID VALID VALID SET RI CLEAR RI 18.4.9. External Clock Drive Characteristics (XTAL1) Symbol Parameter Min Max Units TCLCL Oscillator Period 25 ns TCHCX High Time 5 ns TCLCX Low Time 5 ns TCLCH Rise Time 5 ns TCHCL Fall Time 5 ns 60 % TCHCX/TCLCX Cyclic ratio in X2 mode 40 Table 35. AC Parameters Draft.A - March 30, 2001 113 Preview - Confidential T89C51AC2 18.4.10. External Clock Drive Waveforms VCC-0.5V 0.45V 0.7VCC 0.2VCC-0.1 TCHCX TCLCH TCLCX TCHCL TCLCL 18.4.11. AC Testing Input/Output Waveforms VCC -0.5 V 0.2 VCC + 0.9 INPUT/OUTPUT 0.2 VCC - 0.1 0.45 V AC inputs during testing are driven at VCC - 0.5 for a logic “1” and 0.45V for a logic “0”. Timing measurement are made at VIH min for a logic “1” and VIL max for a logic “0”. 18.4.12. Float Waveforms FLOAT VOH - 0.1 V VOL + 0.1 V VLOAD VLOAD + 0.1 V VLOAD - 0.1 V For timing purposes as 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 loaded VOH/VOL level occurs. IOL/IOH ≥ ± 20mA. 18.4.13. Clock Waveforms Valid in normal clock mode. In X2 mode XTAL2 must be changed to XTAL2/2. 114 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 INTERNAL CLOCK STATE4 STATE5 STATE6 STATE1 STATE2 STATE3 STATE4 STATE5 P1 P1 P1 P1 P1 P1 P1 P1 P2 P2 P2 P2 P2 P2 P2 P2 XTAL2 ALE THESE SIGNALS ARE NOT ACTIVATED DURING THE EXECUTION OF A MOVX INSTRUCTION EXTERNAL PROGRAM MEMORY FETCH PSEN P0 DATA SAMPLED FLOAT P2 (EXT) PCL OUT DATA SAMPLED FLOAT PCL OUT DATA SAMPLED FLOAT PCL OUT INDICATES ADDRESS TRANSITIONS READ CYCLE RD PCL OUT (IF PROGRAM MEMORY IS EXTERNAL) P0 DPL OR Rt OUT DATA SAMPLED FLOAT INDICATES DPH OR P2 SFR TO PCH TRANSITION P2 WRITE CYCLE WR P0 PCL OUT (EVEN IF PROGRAM MEMORY IS INTERNAL) DPL OR Rt OUT PCL OUT (IF PROGRAM MEMORY IS EXTERNAL) DATA OUT P2 INDICATES DPH OR P2 SFR TO PCH TRANSITION PORT OPERATION MOV PORT SRC OLD DATA NEW DATA P0 PINS SAMPLED P0 PINS SAMPLED MOV DEST P0 MOV DEST PORT (P1. P2. P3) (INCLUDES INTO. INT1. TO T1) SERIAL PORT SHIFT CLOCK P1, P2, P3 PINS SAMPLED RXD SAMPLED P1, P2, P3 PINS SAMPLED RXD SAMPLED TXD (MODE 0) This diagram indicates when signals are clocked internally. The time it takes the signals to propagate to the pins, however, ranges from 25 to 125 ns. This propagation delay is dependent on variables such as temperature and pin loading. Propagation also varies from output to output and component. Typically though (TA=25°C fully loaded) RD and WR propagation delays are approximately 50ns. The other signals are typically 85 ns. Propagation delays are incorporated in the AC specifications. Draft.A - March 30, 2001 115 Preview - Confidential T89C51AC2 19. Ordering Information T -RL 89C51AC2 Packages: RL: TQFP44 SL: PLCC44 M C S Temperature Range C:Commercial 0 to 70oC I:Industrial -40 to 85oC E:Enginering Sample 89C51AC2 ( 32 Kbytes Flash ) -M: VCC: 5V 40 MHz, X1 mode 20 MHz, X2 mode Conditioning S: Stick T: Tray 116 Draft.A - March 30, 2001 Preview - Confidential T89C51AC2 Table 36. Possible order entries Extension -SLSCM -SLSIM -RLTCM -RLTIM -SLSEM -RLTEM Type Stick, PLCC44, Com Stick, PLCC44, Ind Tray, TQFP44, Com Tray, TQFP44, Ind Stick, PLCC44, Sample Tray, TQFP44, Sample Draft.A - March 30, 2001 117 Preview - Confidential