INTEGRATED CIRCUITS P87CL52X2/54X2 80C51 8-bit microcontroller family 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) Product data Supersedes data of 2003 Apr 30 2003 May 14 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) DESCRIPTION FEATURES • 8051 Central Processing Unit The Philips P87CL5xX2 is a high-performance static 80C51 design fabricated with Philips high-density CMOS technology with operation from 1.8 V to 3.3 V. – TSSOP or LQFP packages – 256 × 8 RAM The P87CL5xX2 ROMless devices contain a 256 × 8 RAM, 32 I/O lines, three 16-bit counter/timers, a six-source, four-priority level nested interrupt structure, a serial I/O port for either multi-processor communications, I/O expansion or full duplex UART, and on-chip oscillator and clock circuits. – Three 16-bit counter/timers – Boolean processor – Full static operation – Low voltage (1.8 V to 3.3 V@ 12 MHz) operation (12-clock mode) In addition, the device is a low power static design which offers a wide range of operating frequencies down to zero. Two software selectable modes of power reduction — idle mode and power-down mode — are available. The idle mode freezes the CPU while allowing the RAM, time rs, serial port, and interrupt system to continue functioning. The power-down mode saves the RAM contents but freezes the oscillator, causing all other chip functions to be inoperative. Since the design is static, the clock can be stopped without loss of user data and then the execution resumed from the point the clock was stopped. • Memory addressing capability – 64k ROM and 64k RAM • Power control modes: – Clock can be stopped and resumed – Idle mode – Power-down mode • CMOS and TTL compatible • Two speed ranges at VCC = 3.3 V – 0 to 16 MHz (6-clock mode) – 0 to 33 MHz (12-clock mode) • Dual Data Pointers • Four priority interrupt levels • Six interrupt sources • Four 8-bit I/O ports • Full–duplex enhanced UART – Framing error detection – Automatic address recognition • Programmable clock out • Asynchronous port reset • Low EMI (inhibit ALE) • Wake-up from Power Down by an external interrupt 2003 May 14 2 853-2427 29875 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) P87CL5XX2 ORDERING INFORMATION Type number Package Name Description Temperature Range (°C) Version P87CL52X2BDH TSSOP38 plastic thin shrink small outline package; 38 leads; body width 4.4 mm; lead pitch 0.5 mm 0 to +70 SOT510-1 P87CL52X2BBD LQFP44 plastic low profile quad flat package; 44 leads; body 10 x 10 x 1.4 mm 0 to +70 SOT389-1 P87CL54X2BDH TSSOP38 plastic thin shrink small outline package; 38 leads; body width 4.4 mm; lead pitch 0.5 mm 0 to +70 SOT510-1 P87CL54X2BBD LQFP44 plastic low profile quad flat package; 44 leads; body 10 x 10 x 1.4 mm 0 to +70 SOT389-1 NOTE: 1. 80CL52/80CL54 ROM versions are available. The following table illustrates the correlation between operating mode, power supply and maximum external clock frequency: Operating Mode Power Supply Maximum Clock Frequency 6-clock 3.3 V ± 10% 16 MHz 6-clock 1.8 V to 3.3 V 6 MHz 12-clock 3.3 V ± 10% 33 MHz 12-clock 1.8 V to 3.3 V 12 MHz 2003 May 14 3 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) BLOCK DIAGRAM P0.0–P0.7 P2.0–P2.7 PORT 0 DRIVERS PORT 2 DRIVERS VCC VSS RAM ADDR REGISTER PORT 0 LATCH RAM PORT 2 LATCH ROM/EPROM 8 B REGISTER STACK POINTER ACC PROGRAM ADDRESS REGISTER TMP1 TMP2 BUFFER ALU SFRs PC INCREMENTER TIMERS PSW 8 16 PSEN ALE/PROG EA / VPP TIMING AND CONTROL RST INSTRUCTION REGISTER PROGRAM COUNTER PD DPTR’S MULTIPLE PORT 1 LATCH PORT 3 LATCH PORT 1 DRIVERS PORT 3 DRIVERS P1.0–P1.7 P3.0–P3.71 OSCILLATOR XTAL1 XTAL2 su01723 NOTE: 2. P3.2 and 3.5 absent in the TSSOP38 package. 2003 May 14 4 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) LOGIC SYMBOL PLASTIC THIN SHRINK SMALL OUTLINE PACK PIN FUNCTIONS VCC VSS 38 1 PORT 0 XTAL1 ADDRESS AND DATA BUS TSSOP XTAL2 PORT 1 T2 T2EX RST EA/VPP PORT 2 19 RxD TxD INT01 INT1 T0 T11 WR RD PORT 3 SECONDARY FUNCTIONS PSEN ALE/PROG Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 ADDRESS BUS SU01724 NOTE: 1. INT0/P3.2 and T1/P3.5 are absent in the TSSOP38 package. LOW PROFILE QUAD FLAT PACK PIN FUNCTIONS 44 34 1 33 LQFP 11 23 12 Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Function P1.5 P1.6 P1.7 RST P3.0/RxD NIC* P3.1/TxD P3.2/INT0 P3.3/INT1 P3.4/T0 P3.5/T1 P3.6/WR P3.7/RD XTAL2 XTAL1 Pin 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 * NO INTERNAL CONNECTION 2003 May 14 22 Function VSS NIC* P2.0/A8 P2.1/A9 P2.2/A10 P2.3/A11 P2.4/A12 P2.5/A13 P2.6/A14 P2.7/A15 PSEN ALE NIC* EA/VPP P0.7/AD7 Pin 31 32 33 34 35 36 37 38 39 40 41 42 43 44 Function P0.6/AD6 P0.5/AD5 P0.4/AD4 P0.3/AD3 P0.2/AD2 P0.1/AD1 P0.0/AD0 VCC NIC* P1.0/T2 P1.1/T2EX P1.2 P1.3 P1.4 SU01487 5 Function P3.0/RxD P3.1/TxD P3.3/INT1 P3.4/T0 P3.6/WR P3.7/RD XTAL2 XTAL1 VSS P2.0/A8 P2.1/A9 P2.2/A10 P2.3/A11 20 Pin 14 15 16 17 18 19 20 21 22 23 24 25 26 Function P2.4/A12 P2.5/A13 P2.6/A14 P2.7/A15 PSEN ALE/PROG EA/VPP P0.7/AD7 P0.6/AD6 P0.5/AD5 P0.4/AD4 P0.3/AD3 P0.2/AD2 Pin 27 28 29 30 31 32 33 34 35 36 37 38 Function P0.1/AD1 P0.0/AD0 VDD P1.0/T2 P1.1/T2EX P1.2 P1.3 P1.4 P1.5 P1.6 P1.7 RST su01725 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) PIN DESCRIPTIONS PIN NUMBER MNEMONIC LQFP TSSOP TYPE NAME AND FUNCTION VSS 16 9 I Ground: 0 V reference. VCC 38 29 I Power Supply: This is the power supply voltage for normal, idle, and power-down operation. P0.0–0.7 37–30 28–21 I/O Port 0: Port 0 is an open-drain, bidirectional I/O port with Schmitt trigger inputs. Port 0 pins that have 1s written to them float and 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 pull-ups when emitting 1s. P1.0–P1.7 40–44, 1–3 30–37 I/O 40 41 30 31 I/O I Port 1: Port 1 is an 8-bit bidirectional I/O port with internal pull-ups and Schmitt trigger inputs. Port 1 pins that have 1s written to them are pulled high by the internal pull-ups and can be used as inputs. As inputs, port 1 pins that are externally pulled low will source current because of the internal pull-ups. (See DC Electrical Characteristics: IIL). Alternate functions for Port 1 include: T2 (P1.0): Timer/Counter 2 external count input/clockout (see Programmable Clock-Out) T2EX (P1.1): Timer/Counter 2 Reload/Capture/Direction control P2.0–P2.7 18–25 10–17 I/O Port 2: Port 2 is an 8-bit bidirectional I/O port with internal pull-ups and Schmitt trigger inputs. Port 2 pins that have 1s written to them are pulled high by the internal pull-ups and can be used as inputs. As inputs, port 2 pins that are externally being pulled low will source current because of the internal pull-ups. (See DC Electrical Characteristics: IIL). Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses (MOVX @DPTR). In this application, it uses strong internal pull-ups when emitting 1s. During accesses to external data memory that use 8-bit addresses (MOV @Ri), port 2 emits the contents of the P2 special function register. P3.0–P3.7 5, 7–13 1–6 I/O 5 7 8 9 10 11 12 13 1 2 5 6 I O I I I I O O Port 3: Port 3 is an 8-bit bidirectional I/O port with internal pull-ups and Schmitt trigger inputs. Port 3 pins that have 1s written to them are pulled high by the internal pull-ups and can be used as inputs. As inputs, port 3 pins that are externally being pulled low will source current because of the pull-ups. (See DC Electrical Characteristics: IIL). Port 3 also serves the special features of the 80C51 family, as listed below: RxD (P3.0): Serial input port TxD (P3.1): Serial output port INT0 (P3.2): External interrupt1 INT1 (P3.3): External interrupt T0 (P3.4): Timer 0 external input T1 (P3.5): Timer 1 external input1 WR (P3.6): External data memory write strobe RD (P3.7): External data memory read strobe RST 4 38 I ALE 27 19 O PSEN 26 18 O Program Store Enable: The read strobe to external program memory. When the P87CL5xX2 is executing code from the external program memory, PSEN is activated twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory. PSEN is not activated during fetches from internal program memory. EA/VPP 29 20 I XTAL1 15 8 I External Access Enable/Programming Supply Voltage: EA must be externally held low to enable the device to fetch code from external program memory locations 0000H to 0FFFH. Crystal 1: Input to the inverting oscillator amplifier and input to the internal clock generator circuits. 3 4 Reset: A high on this pin for two machine cycles while the oscillator is running, resets the device. An internal diffused resistor to VSS permits a power-on reset using only an external capacitor to VCC. Address Latch Enable: Output pulse for latching the low byte of the address during an access to external memory. In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency, and can be used for external timing or clocking. Note that one ALE pulse is skipped during each access to external data memory. ALE can be disabled by setting SFR auxiliary.0. With this bit set, ALE will be active only during a MOVX instruction. XTAL2 14 7 O Crystal 2: Output from the inverting oscillator amplifier. NOTE: To avoid “latch-up” effect at power-on, the voltage on any pin at any time must not be higher than VCC + 0.5 V or VSS – 0.5 V, respectively. 1. Absent in the TSSOP38 package. 2003 May 14 6 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) Table 1. SYMBOL P87CL5xX2 Special Function Registers DESCRIPTION DIRECT ADDRESS ACC* AUXR# AUXR1# B* CKCON DPTR: DPH DPL Accumulator Auxiliary Auxiliary 1 B register Clock Control Register Data Pointer (2 bytes) Data Pointer High Data Pointer Low E0H 8EH A2H F0H 8FH IE* Interrupt Enable A8H IP* Interrupt Priority B8H IPH# Interrupt Priority High B7H P0* Port 0 80H P1* Port 1 90H P2* Port 2 A0H P3* Port 3 B0H PCON#1 Power Control 87H PSW* RACAP2H# RACAP2L# SADDR# SADEN# SBUF Program Status Word Timer 2 Capture High Timer 2 Capture Low Slave Address Slave Address Mask Serial Data Buffer D0H CBH CAH A9H B9H 99H SCON* SP Serial Control Stack Pointer 98H 81H TCON* Timer Control 88H BIT ADDRESS, SYMBOL, OR ALTERNATIVE PORT FUNCTION MSB E7 – – F7 – E6 – – F6 – E5 – – F5 – E4 – – F4 – E3 – WUPD F3 – E2 – 0 F2 – E1 – – F1 – LSB E0 AO DPS F0 X2 83H 82H 00H xxxxxxx0B xxx000x0B 00H xxx00000B 00H 00H AF EA BF – B7 – 87 AD7 97 – A7 AD15 B7 RD AE – BE – B6 – 86 AD6 96 – A6 AD14 B6 WR AD ET2 BD PT2 B5 PT2H 85 AD5 95 – A5 AD13 B5 T1 AC ES BC PS B4 PSH 84 AD4 94 – A4 AD12 B4 T0 AB ET1 BB PT1 B3 PT1H 83 AD3 93 – A3 AD11 B3 INT1 AA EX1 BA PX1 B2 PX1H 82 AD2 92 – A2 AD10 B2 INT0 A9 ET0 B9 PT0 B1 PT0H 81 AD1 91 T2EX A1 AD9 B1 TxD A8 EX0 B8 PX0 B0 PX0H 80 AD0 90 T2 A0 AD8 B0 RxD SMOD1 D7 CY SMOD0 D6 AC – D5 F0 POF D4 RS1 GF1 D3 RS0 GF0 D2 OV PD D1 – IDL D0 P 9F SM0/FE 9E SM1 9D SM2 9C REN 9B TB8 9A RB8 99 TI 98 RI 8F TF1 CF TF2 – 8E TR1 CE EXF2 – 8D TF0 CD RCLK – 8C TR0 CC TCLK – 8B IE1 CB EXEN2 – 8A IT1 CA TR2 – 89 IE0 C9 C/T2 T2OE 88 IT0 C8 CP/RL2 DCEN T2CON* Timer 2 Control C8H T2MOD# Timer 2 Mode Control C9H TH0 Timer High 0 8CH TH1 Timer High 1 8DH TH2# Timer High 2 CDH TL0 Timer Low 0 8AH TL1 Timer Low 1 8BH TL2# Timer Low 2 CCH TMOD Timer Mode 89H GATE C/T M1 M0 GATE C/T M1 M0 NOTE: Unused register bits that are not defined should not be set by the user’s program. If violated, the device could function incorrectly. * SFRs are bit addressable. # SFRs are modified from or added to the 80C51 SFRs. – Reserved bits. 1. Reset value depends on reset source. 2003 May 14 RESET VALUE 7 0x000000B xx000000B xx000000B FFH FFH FFH FFH 00xx0000B 000000x0B 00H 00H 00H 00H xxxxxxxxB 00H 07H 00H 00H xxxxxx00B 00H 00H 00H 00H 00H 00H 00H Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) the instruction that invoked Power Down is the last instruction executed. The on-chip RAM and Special Function Registers retain their values down to 2.0 V and care must be taken to return VCC to the minimum specified operating voltages before the Power Down Mode is terminated. OSCILLATOR CHARACTERISTICS XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier. The pins can be configured for use as an on-chip oscillator, as shown in the logic symbol. To drive the device from an external clock source, XTAL1 should be driven while XTAL2 is left unconnected. There are no requirements on the duty cycle of the external clock signal, because the input to the internal clock circuitry is through a divide-by-two flip-flop. However, minimum and maximum high and low times specified in the data sheet must be observed. For the P87CL5xX2, either a hardware reset or external interrupt can be used to exit from Power Down. Reset redefines all the SFRs but does not change the on-chip RAM. An external interrupt allows both the SFRs and the on-chip RAM to retain their values. WUPD (AUXR1.3–Wakeup from Power Down) enables or disables the wakeup from power down with external interrupt. Where: Clock Control Register (CKCON) WUPD = 0 Disable WUPD = 1 Enable This device provides control of the 6-clock/12-clock mode by an SFR bit (bit X2 in register CKCON). When X2 is 0, 12-clock mode is activated. By setting this bit to 1, the system is switching to 6-clock mode. Having this option implemented as SFR bit, it can be accessed anytime and changed to either value. Changing X2 from 0 to 1 will result in executing user code at twice the speed, since all system time intervals will be divided by 2. Changing back from 6-clock to 12-clock mode will slow down running code by a factor of 2. To properly terminate Power Down the reset or external interrupt should not be executed before VCC is restored to its normal operating level and must be held active long enough for the oscillator to restart and stabilize (normally less than 10 ms). With an external interrupt, INT0 or INT1 must be enabled and configured as level-sensitive. Holding the pin low restarts the oscillator but bringing the pin back high completes the exit. Once the interrupt is serviced, the next instruction to be executed after RETI will be the one following the instruction that put the device into Power Down. Reset A reset is accomplished by holding the RST pin high for at least two machine cycles (24 oscillator periods), while the oscillator is running. To insure a good power-up reset, the RST pin must be high long enough to allow the oscillator time to start up (normally a few milliseconds) plus two machine cycles. Design Consideration • When the idle mode is terminated by a hardware reset, the device normally resumes program execution, from where it left off, up to two machine cycles before the internal reset algorithm takes control. On-chip hardware inhibits access to internal RAM in this event, but access to the port pins is not inhibited. To eliminate the possibility of an unexpected write when Idle is terminated by reset, the instruction following the one that invokes Idle should not be one that writes to a port pin or to external memory. Stop Clock Mode The static design enables the clock speed to be reduced down to 0 MHz (stopped). When the oscillator is stopped, the RAM and Special Function Registers retain their values. This mode allows step-by-step utilization and permits reduced system power consumption by lowering the clock frequency down to any value. For lowest power consumption the Power Down mode is suggested. ONCE Mode The ONCE (“On-Circuit Emulation”) Mode facilitates testing and debugging of systems without the device having to be removed from the circuit. The ONCE Mode is invoked by: Idle Mode In idle mode (see Table 2), the CPU puts itself to sleep while all of the on-chip peripherals stay active. The instruction to invoke the idle mode is the last instruction executed in the normal operating mode before the idle mode is activated. The CPU contents, the on-chip RAM, and all of the special function registers remain intact during this mode. The idle mode can be terminated either by any enabled interrupt (at which time the process is picked up at the interrupt service routine and continued), or by a hardware reset which starts the processor in the same manner as a power-on reset. 1. Pull ALE low while the device is in reset and PSEN is high; 2. Hold ALE low as RST is deactivated. While the device is in ONCE Mode, the Port 0 pins go into a float state, and the other port pins and ALE and PSEN are weakly pulled high. The oscillator circuit remains active. While the P87CL5xX2 is in this mode, an emulator or test CPU can be used to drive the circuit. Normal operation is restored when a normal reset is applied. Power-Down Mode To save even more power, a Power Down mode (see Table 2) can be invoked by software. In this mode, the oscillator is stopped and Table 2. External Pin Status During Idle and Power-Down Modes PROGRAM MEMORY ALE PSEN PORT 0 PORT 1 PORT 2 PORT 3 Idle MODE Internal 1 1 Data Data Data Data Idle External 1 1 Float Data Address Data Power-down Internal 0 0 Data Data Data Data Power-down External 0 0 Float Data Data Data 2003 May 14 8 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) In this mode, the Timer register is configured as a 13-bit register. As the count rolls over from all 1s to all 0s, it sets the Timer interrupt flag TFn. The counted input is enabled to the Timer when TRn = 1 and either GATE = 0 or INTn = 1. (Setting GATE = 1 allows the Timer to be controlled by external input INTn, to facilitate pulse width measurements). TRn is a control bit in the Special Function Register TCON (Figure 3). Programmable Clock-Out A 50% duty cycle clock can be programmed to come out on P1.0. This pin, besides being a regular I/O pin, has two alternate functions. It can be programmed: 1. to input the external clock for Timer/Counter 2, or 2. to output a 50% duty cycle clock ranging from 61 Hz to 4 MHz at a 16 MHz operating frequency. The 13-bit register consists of all 8 bits of THn and the lower 5 bits of TLn. The upper 3 bits of TLn are indeterminate and should be ignored. Setting the run flag (TRn) does not clear the registers. To configure the Timer/Counter 2 as a clock generator, bit C/T2 (in T2CON) must be cleared and bit T20E in T2MOD must be set. Bit TR2 (T2CON.2) also must be set to start the timer. Mode 0 operation is the same for Timer 0 as for Timer 1. There are two different GATE bits, one for Timer 1 (TMOD.7) and one for Timer 0 (TMOD.3). The Clock-Out frequency depends on the oscillator frequency and the reload value of Timer 2 capture registers (RCAP2H, RCAP2L) as shown in this equation: 4 Mode 1 Mode 1 is the same as Mode 0, except that the Timer register is being run with all 16 bits. Oscillator Frequency (65536 * RCAP2H, RCAP2L) Where: Mode 2 Mode 2 configures the Timer register as an 8-bit Counter (TLn) with automatic reload, as shown in Figure 4. Overflow from TLn not only sets TFn, but also reloads TLn with the contents of THn, which is preset by software. The reload leaves THn unchanged. (RCAP2H,RCAP2L) = the content of RCAP2H and RCAP2L taken as a 16-bit unsigned integer. In the Clock-Out mode Timer 2 roll-overs will not generate an interrupt. This is similar to when it is used as a baud-rate generator. It is possible to use Timer 2 as a baud-rate generator and a clock generator simultaneously. Note, however, that the baud-rate and the Clock-Out frequency will be the same. Mode 2 operation is the same for Timer 0 as for Timer 1. Mode 3 Timer 1 in Mode 3 simply holds its count. The effect is the same as setting TR1 = 0. TIMER 0 AND TIMER 1 OPERATION Timer 0 in Mode 3 establishes TL0 and TH0 as two separate counters. The logic for Mode 3 on Timer 0 is shown in Figure 5. TL0 uses the Timer 0 control bits: C/T, GATE, TR0, and TF0 as well as pin INT0. TH0 is locked into a timer function (counting machine cycles) and takes over the use of TR1 and TF1 from Timer 1. Thus, TH0 now controls the “Timer 1” interrupt. Timer 0 and Timer 1 The “Timer” or “Counter” function is selected by control bits C/T in the Special Function Register TMOD. These two Timer/Counters have four operating modes, which are selected by bit-pairs (M1, M0) in TMOD. Modes 0, 1, and 2 are the same for both Timers/Counters. Mode 3 is different. The four operating modes are described in the following text. Mode 3 is provided for applications requiring an extra 8-bit timer on the counter. With Timer 0 in Mode 3, an 80C51 can look like it has three Timer/Counters. When Timer 0 is in Mode 3, Timer 1 can be turned on and off by switching it out of and into its own Mode 3, or can still be used by the serial port as a baud rate generator, or in fact, in any application not requiring an interrupt. Mode 0 Putting either Timer into Mode 0 makes it look like an 8048 Timer, which is an 8-bit Counter with a divide-by-32 prescaler. Figure 2 shows the Mode 0 operation. 2003 May 14 9 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) TMOD Address = 89H Reset Value = 00H Not Bit Addressable 7 6 5 4 3 2 1 0 GATE C/T M1 M0 GATE C/T M1 M0 TIMER 1 BIT TMOD.3/ TMOD.7 TMOD.2/ TMOD.6 SYMBOL GATE C/T TIMER 0 FUNCTION Gating control when set. Timer/Counter “n” is enabled only while “INTn” pin is high and “TRn” control pin is set. when cleared Timer “n” is enabled whenever “TRn” control bit is set. Timer or Counter Selector cleared for Timer operation (input from internal system clock.) Set for Counter operation (input from “Tn” input pin). M1 M0 OPERATING 0 0 8048 Timer: “TLn” serves as 5-bit prescaler. 0 1 16-bit Timer/Counter: “THn” and “TLn” are cascaded; there is no prescaler. 1 0 8-bit auto-reload Timer/Counter: “THn” holds a value which is to be reloaded into “TLn” each time it overflows. 1 1 (Timer 0) TL0 is an 8-bit Timer/Counter controlled by the standard Timer 0 control bits. TH0 is an 8-bit timer only controlled by Timer 1 control bits. 1 1 (Timer 1) Timer/Counter 1 stopped. SU01580 Figure 1. Timer/Counter 0/1 Mode Control (TMOD) Register ÷ d* OSC C/T = 0 TLn (5 Bits) THn (8 Bits) TFn Interrupt C/T = 1 Control Tn Pin TRn Timer n Gate bit INTn Pin *d = 6 in 6-clock mode; d = 12 in 12-clock mode. SU01618 Figure 2. Timer/Counter 0/1 Mode 0: 13-Bit Timer/Counter 2003 May 14 10 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) TCON Address = 88H Reset Value = 00H Bit Addressable 7 TF1 BIT TCON.7 SYMBOL TF1 TCON.6 TCON.5 TR1 TF0 TCON.4 TCON.3 TR0 IE1 TCON.2 IT1 TCON.1 IE0 TCON.0 IT0 6 5 4 3 2 1 0 TR1 TF0 TR0 IE1 IT1 IE0 IT0 FUNCTION Timer 1 overflow flag. Set by hardware on Timer/Counter overflow. Cleared by hardware when processor vectors to interrupt routine, or clearing the bit in software. Timer 1 Run control bit. Set/cleared by software to turn Timer/Counter on/off. Timer 0 overflow flag. Set by hardware on Timer/Counter overflow. Cleared by hardware when processor vectors to interrupt routine, or by clearing the bit in software. Timer 0 Run control bit. Set/cleared by software to turn Timer/Counter on/off. Interrupt 1 Edge flag. Set by hardware when external interrupt edge detected. Cleared when interrupt processed. Interrupt 1 type control bit. Set/cleared by software to specify falling edge/low level triggered external interrupts. Interrupt 0 Edge flag. Set by hardware when external interrupt edge detected. Cleared when interrupt processed. Interrupt 0 Type control bit. Set/cleared by software to specify falling edge/low level triggered external interrupts. SU01516 Figure 3. Timer/Counter 0/1 Control (TCON) Register ÷ d* OSC C/T = 0 TLn (8 Bits) TFn Interrupt C/T = 1 Control Tn Pin Reload TRn Timer n Gate bit THn (8 Bits) INTn Pin SU01619 *d = 6 in 6-clock mode; d = 12 in 12-clock mode. Figure 4. Timer/Counter 0/1 Mode 2: 8-Bit Auto-Reload 2003 May 14 11 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) ÷ d* OSC C/T = 0 TL0 (8 Bits) TF0 Interrupt TH0 (8 Bits) TF1 Interrupt C/T = 1 Control T0 Pin TR0 Timer 0 Gate bit INT0 Pin OSC ÷ d* Control TR1 *d = 6 in 6-clock mode; d = 12 in 12-clock mode. SU01620 Figure 5. Timer/Counter 0 Mode 3: Two 8-Bit Counters Figure 3). When reset is applied the DCEN = 0 which means Timer 2 will default to counting up. If DCEN bit is set, Timer 2 can count up or down depending on the value of the T2EX pin. TIMER 2 OPERATION Timer 2 Timer 2 is a 16-bit Timer/Counter which can operate as either an event timer or an event counter, as selected by C/T2* in the special function register T2CON (see Figure 1). Timer 2 has three operating modes:Capture, Auto-reload (up or down counting) ,and Baud Rate Generator, which are selected by bits in the T2CON as shown in Table 3. Figure 4 shows Timer 2 which will count up automatically since DCEN = 0. In this mode there are two options selected by bit EXEN2 in T2CON register. If EXEN2 = 0, then Timer 2 counts up to 0FFFFH and sets the TF2 (Overflow Flag) bit upon overflow. This causes the Timer 2 registers to be reloaded with the 16-bit value in RCAP2L and RCAP2H. The values in RCAP2L and RCAP2H are preset by software means. Capture Mode In the capture mode there are two options which are selected by bit EXEN2 in T2CON. If EXEN2 = 0, then timer 2 is a 16-bit timer or counter (as selected by C/T2* in T2CON) which, upon overflowing sets bit TF2, the timer 2 overflow bit. This bit can be used to generate an interrupt (by enabling the Timer 2 interrupt bit in the IE register). If EXEN2 = 1, Timer 2 operates as described above, but with the added feature that a 1- to -0 transition at external input T2EX causes the current value in the Timer 2 registers, TL2 and TH2, to be captured into registers RCAP2L and RCAP2H, respectively. In addition, the transition at T2EX causes bit EXF2 in T2CON to be set, and EXF2 like TF2 can generate an interrupt (which vectors to the same location as Timer 2 overflow interrupt. The Timer 2 interrupt service routine can interrogate TF2 and EXF2 to determine which event caused the interrupt). The capture mode is illustrated in Figure 2 (There is no reload value for TL2 and TH2 in this mode. Even when a capture event occurs from T2EX, the counter keeps on counting T2EX pin transitions or osc/12 pulses.). If EXEN2 = 1, then a 16-bit reload can be triggered either by an overflow or by a 1-to-0 transition at input T2EX. This transition also sets the EXF2 bit. The Timer 2 interrupt, if enabled, can be generated when either TF2 or EXF2 are 1. Auto-Reload Mode (Up or Down Counter) The external flag EXF2 toggles when Timer 2 underflows or overflows. This EXF2 bit can be used as a 17th bit of resolution if needed. The EXF2 flag does not generate an interrupt in this mode of operation. In Figure 5 DCEN = 1 which enables Timer 2 to count up or down. This mode allows pin T2EX to control the direction of count. When a logic 1 is applied at pin T2EX Timer 2 will count up. Timer 2 will overflow at 0FFFFH and set the TF2 flag, which can then generate an interrupt, if the interrupt is enabled. This timer overflow also causes the 16–bit value in RCAP2L and RCAP2H to be reloaded into the timer registers TL2 and TH2. When a logic 0 is applied at pin T2EX this causes Timer 2 to count down. The timer will underflow when TL2 and TH2 become equal to the value stored in RCAP2L and RCAP2H. Timer 2 underflow sets the TF2 flag and causes 0FFFFH to be reloaded into the timer registers TL2 and TH2. In the 16-bit auto-reload mode, Timer 2 can be configured (as either a timer or counter (C/T2* in T2CON)) then programmed to count up or down. The counting direction is determined by bit DCEN (Down Counter Enable) which is located in the T2MOD register (see 2003 May 14 12 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) Table 3. Timer 2 Operating Modes RCLK + TCLK CP/RL2 TR2 MODE 0 0 1 16-bit Auto-reload 0 1 1 16-bit Capture 1 X 1 Baud rate generator X X 0 (off) (MSB) TF2 (LSB) EXF2 RCLK TCLK EXEN2 TR2 C/T2 CP/RL2 Symbol Position Name and Significance TF2 T2CON.7 EXF2 T2CON.6 RCLK T2CON.5 TCLK T2CON.4 EXEN2 T2CON.3 TR2 C/T2 T2CON.2 T2CON.1 CP/RL2 T2CON.0 Timer 2 overflow flag set by a Timer 2 overflow and must be cleared by software. TF2 will not be set when either RCLK or TCLK = 1. Timer 2 external flag set when either a capture or reload is caused by a negative transition on T2EX and EXEN2 = 1. When Timer 2 interrupt is enabled, EXF2 = 1 will cause the CPU to vector to the Timer 2 interrupt routine. EXF2 must be cleared by software. EXF2 does not cause an interrupt in up/down counter mode (DCEN = 1). Receive clock flag. When set, causes the serial port to use Timer 2 overflow pulses for its receive clock in modes 1 and 3. RCLK = 0 causes Timer 1 overflow to be used for the receive clock. Transmit clock flag. When set, causes the serial port to use Timer 2 overflow pulses for its transmit clock in modes 1 and 3. TCLK = 0 causes Timer 1 overflows to be used for the transmit clock. Timer 2 external enable flag. When set, allows a capture or reload to occur as a result of a negative transition on T2EX if Timer 2 is not being used to clock the serial port. EXEN2 = 0 causes Timer 2 to ignore events at T2EX. Start/stop control for Timer 2. A logic 1 starts the timer. Timer or counter select. (Timer 2) 0 = Internal timer (OSC/12) 1 = External event counter (falling edge triggered). Capture/Reload flag. When set, captures will occur on negative transitions at T2EX if EXEN2 = 1. When cleared, auto-reloads will occur either with Timer 2 overflows or negative transitions at T2EX when EXEN2 = 1. When either RCLK = 1 or TCLK = 1, this bit is ignored and the timer is forced to auto-reload on Timer 2 overflow. SU00728 Figure 1. Timer/Counter 2 (T2CON) Control Register 2003 May 14 13 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) OSC ÷ 12 C/T2 = 0 TL2 (8-bits) TH2 (8-bits) TF2 C/T2 = 1 T2 Pin Control TR2 Capture Transition Detector Timer 2 Interrupt RCAP2L RCAP2H T2EX Pin EXF2 Control EXEN2 SU00066 Figure 2. Timer 2 in Capture Mode T2MOD Address = 0C9H Reset Value = XXXX XX00B Not Bit Addressable Bit * — — — — — — T2OE DCEN 7 6 5 4 3 2 1 0 Symbol Function — Not implemented, reserved for future use.* T2OE Timer 2 Output Enable bit. DCEN Down Count Enable bit. When set, this allows Timer 2 to be configured as an up/down counter. User software should not write 1s to reserved bits. These bits may be used in future 8051 family products to invoke new features. In that case, the reset or inactive value of the new bit will be 0, and its active value will be 1. The value read from a reserved bit is indeterminate. SU00729 Figure 3. Timer 2 Mode (T2MOD) Control Register 2003 May 14 14 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) ÷ 12 OSC C/T2 = 0 TL2 (8-BITS) TH2 (8-BITS) C/T2 = 1 T2 PIN CONTROL TR2 RELOAD TRANSITION DETECTOR RCAP2L RCAP2H TF2 TIMER 2 INTERRUPT T2EX PIN EXF2 CONTROL SU00067 EXEN2 Figure 4. Timer 2 in Auto-Reload Mode (DCEN = 0) (DOWN COUNTING RELOAD VALUE) FFH FFH TOGGLE EXF2 OSC ÷12 C/T2 = 0 OVERFLOW TL2 T2 PIN TH2 TF2 INTERRUPT C/T2 = 1 CONTROL TR2 COUNT DIRECTION 1 = UP 0 = DOWN RCAP2L RCAP2H (UP COUNTING RELOAD VALUE) Figure 5. Timer 2 Auto Reload Mode (DCEN = 1) 2003 May 14 15 T2EX PIN SU00730 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) Timer 1 Overflow ÷2 NOTE: OSC. Freq. is divided by 2, not 12. OSC “0” ÷2 “1” C/T2 = 0 SMOD TL2 (8-bits) “1” TH2 (8-bits) “0” RCLK C/T2 = 1 T2 Pin Control ÷ 16 “1” TR2 Reload Transition Detector RCAP2L T2EX Pin EXF2 RCAP2H RX Clock “0” TCLK ÷ 16 TX Clock Timer 2 Interrupt Control EXEN2 Note availability of additional external interrupt. Figure 6. Timer 2 in Baud Rate Generator Mode 2003 May 14 16 SU00068 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) under these conditions, a read or write of TH2 or TL2 may not be accurate. The RCAP2 registers may be read, but should not be written to, because a write might overlap a reload and cause write and/or reload errors. The timer should be turned off (clear TR2) before accessing the Timer 2 or RCAP2 registers. Baud Rate Generator Mode Bits TCLK and/or RCLK in T2CON (Table 3) allow the serial port transmit and receive baud rates to be derived from either Timer 1 or Timer 2. When TCLK = 0, Timer 1 is used as the serial port transmit baud rate generator. When TCLK= 1, Timer 2 is used as the serial port transmit baud rate generator. RCLK has the same effect for the serial port receive baud rate. With these two bits, the serial port can have different receive and transmit baud rates – one generated by Timer 1, the other by Timer 2. Table 4 shows commonly used baud rates and how they can be obtained from Timer 2. Table 4. Figure 6 shows the Timer 2 in baud rate generation mode. The baud rate generation mode is like the auto-reload mode, in that a rollover in TH2 causes the Timer 2 registers to be reloaded with the 16-bit value in registers RCAP2H and RCAP2L, which are preset by software. Timer 2 The baud rates in modes 1 and 3 are determined by Timer 2’s overflow rate given below: Modes 1 and 3 Baud Rates + Timer 2 Overflow Rate 16 The timer can be configured for either “timer” or “counter” operation. In many applications, it is configured for “timer” operation (C/T2* = 0). Timer operation is different for Timer 2 when it is being used as a baud rate generator. Usually, as a timer it would increment every machine cycle (i.e., 1/12 the oscillator frequency). As a baud rate generator, it increments every state time (i.e., 1/2 the oscillator frequency). Thus the baud rate formula is as follows: Ba d Rate Baud Osc Freq 375 K 9.6 K 2.8 K 2.4 K 1.2 K 300 110 300 110 12 MHz 12 MHz 12 MHz 12 MHz 12 MHz 12 MHz 12 MHz 6 MHz 6 MHz RCAP2H RCAP2L FF FF FF FF FE FB F2 FD F9 FF D9 B2 64 C8 1E AF 8F 57 Summary Of Baud Rate Equations Timer 2 is in baud rate generating mode. If Timer 2 is being clocked through pin T2(P1.0) the baud rate is: Baud Rate + Timer 2 Overflow Rate 16 Modes 1 and 3 Baud Rates = Oscillator Frequency [32 [65536 * (RCAP2H, RCAP2L)]] If Timer 2 is being clocked internally, the baud rate is: Where: (RCAP2H, RCAP2L) = The content of RCAP2H and RCAP2L taken as a 16-bit unsigned integer. Baud Rate + The Timer 2 as a baud rate generator mode shown in Figure 6, is valid only if RCLK and/or TCLK = 1 in T2CON register. Note that a rollover in TH2 does not set TF2, and will not generate an interrupt. Thus, the Timer 2 interrupt does not have to be disabled when Timer 2 is in the baud rate generator mode. Also if the EXEN2 (T2 external enable flag) is set, a 1-to-0 transition in T2EX (Timer/counter 2 trigger input) will set EXF2 (T2 external flag) but will not cause a reload from (RCAP2H, RCAP2L) to (TH2,TL2). Therefore when Timer 2 is in use as a baud rate generator, T2EX can be used as an additional external interrupt, if needed. [32 f OSC [65536 * (RCAP2H, RCAP2L)]] Where fOSC = Oscillator Frequency To obtain the reload value for RCAP2H and RCAP2L, the above equation can be rewritten as: RCAP2H, RCAP2L + 65536 * ǒ 32 Ǔ f OSC Baud Rate Timer/Counter 2 Set-up Except for the baud rate generator mode, the values given for T2CON do not include the setting of the TR2 bit. Therefore, bit TR2 must be set, separately, to turn the timer on. See Table 5 for set-up of Timer 2 as a timer. Also see Table 6 for set-up of Timer 2 as a counter. When Timer 2 is in the baud rate generator mode, one should not try to read or write TH2 and TL2. As a baud rate generator, Timer 2 is incremented every state time (osc/2) or asynchronously from pin T2; 2003 May 14 Timer 2 Generated Commonly Used Baud Rates 17 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) Table 5. Timer 2 as a Timer MODE T2CON INTERNAL CONTROL (Note 1) EXTERNAL CONTROL (Note 2) 16-bit Auto-Reload 00H 08H 16-bit Capture 01H 09H Baud rate generator receive and transmit same baud rate 34H 36H Receive only 24H 26H Transmit only 14H 16H Table 6. Timer 2 as a Counter MODE TMOD INTERNAL CONTROL (Note 1) EXTERNAL CONTROL (Note 2) 16-bit 02H 0AH Auto-Reload 03H 0BH NOTES: 1. Capture/reload occurs only on timer/counter overflow. 2. Capture/reload occurs on timer/counter overflow and a 1-to-0 transition on T2EX (P1.1) pin except when Timer 2 is used in the baud rate generator mode. 2003 May 14 18 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) The slaves that weren’t being addressed leave their SM2s set and go on about their business, ignoring the coming data bytes. FULL-DUPLEX ENHANCED UART Standard UART operation SM2 has no effect in Mode 0, and in Mode 1 can be used to check the validity of the stop bit. In a Mode 1 reception, if SM2 = 1, the receive interrupt will not be activated unless a valid stop bit is received. The serial port is full duplex, meaning it can transmit and receive simultaneously. It is also receive-buffered, meaning it can commence reception of a second byte before a previously received byte has been read from the register. (However, if the first byte still hasn’t been read by the time reception of the second byte is complete, one of the bytes will be lost.) The serial port receive and transmit registers are both accessed at Special Function Register SBUF. Writing to SBUF loads the transmit register, and reading SBUF accesses a physically separate receive register. Serial Port Control Register The serial port control and status register is the Special Function Register SCON, shown in Figure 7. This register contains not only the mode selection bits, but also the 9th data bit for transmit and receive (TB8 and RB8), and the serial port interrupt bits (TI and RI). The serial port can operate in 4 modes: Mode 0: Serial data enters and exits through RxD. TxD outputs the shift clock. 8 bits are transmitted/received (LSB first). The baud rate is fixed at 1/12 the oscillator frequency in 12-clock mode or 1/6 the oscillator frequency in 6-clock mode. Mode 1: 10 bits are transmitted (through TxD) or received (through RxD): a start bit (0), 8 data bits (LSB first), and a stop bit (1). On receive, the stop bit goes into RB8 in Special Function Register SCON. The baud rate is variable. Mode 2: Mode 3: Baud Rates The baud rate in Mode 0 is fixed: Mode 0 Baud Rate = Oscillator Frequency / 12 (12-clock mode) or / 6 (6-clock mode). The baud rate in Mode 2 depends on the value of bit SMOD in Special Function Register PCON. If SMOD = 0 (which is the value on reset), and the port pins in 12-clock mode, the baud rate is 1/64 the oscillator frequency. If SMOD = 1, the baud rate is 1/32 the oscillator frequency. In 6-clock mode, the baud rate is 1/32 or 1/16 the oscillator frequency, respectively. Mode 2 Baud Rate = 2 SMOD n 11 bits are transmitted (through TxD) or received (through RxD): start bit (0), 8 data bits (LSB first), a programmable 9th data bit, and a stop bit (1). On Transmit, the 9th data bit (TB8 in SCON) can be assigned the value of 0 or 1. Or, for example, the parity bit (P, in the PSW) could be moved into TB8. On receive, the 9th data bit goes into RB8 in Special Function Register SCON, while the stop bit is ignored. The baud rate is programmable to either 1/32 or 1/64 the oscillator frequency in 12-clock mode or 1/16 or 1/32 the oscillator frequency in 6-clock mode. Where: n = 64 in 12-clock mode, 32 in 6-clock mode The baud rates in Modes 1 and 3 are determined by the Timer 1 or Timer 2 overflow rate. Using Timer 1 to Generate Baud Rates When Timer 1 is used as the baud rate generator (T2CON.RCLK = 0, T2CON.TCLK = 0), the baud rates in Modes 1 and 3 are determined by the Timer 1 overflow rate and the value of SMOD as follows: 11 bits are transmitted (through TxD) or received (through RxD): a start bit (0), 8 data bits (LSB first), a programmable 9th data bit, and a stop bit (1). In fact, Mode 3 is the same as Mode 2 in all respects except baud rate. The baud rate in Mode 3 is variable. Mode 1, 3 Baud Rate = 2 SMOD n (Timer 1 Overflow Rate) Where: In all four modes, transmission is initiated by any instruction that uses SBUF as a destination register. Reception is initiated in Mode 0 by the condition RI = 0 and REN = 1. Reception is initiated in the other modes by the incoming start bit if REN = 1. n = 32 in 12-clock mode, 16 in 6-clock mode The Timer 1 interrupt should be disabled in this application. The Timer itself can be configured for either “timer” or “counter” operation, and in any of its 3 running modes. In the most typical applications, it is configured for “timer” operation, in the auto-reload mode (high nibble of TMOD = 0010B). In that case the baud rate is given by the formula: Multiprocessor Communications Modes 2 and 3 have a special provision for multiprocessor communications. In these modes, 9 data bits are received. The 9th one goes into RB8. Then comes a stop bit. The port can be programmed such that when the stop bit is received, the serial port interrupt will be activated only if RB8 = 1. This feature is enabled by setting bit SM2 in SCON. A way to use this feature in multiprocessor systems is as follows: Mode 1, 3 Baud Rate = 2 SMOD n Oscillator Frequency 12 [256–(TH1)] Where: When the master processor wants to transmit a block of data to one of several slaves, it first sends out an address byte which identifies the target slave. An address byte differs from a data byte in that the 9th bit is 1 in an address byte and 0 in a data byte. With SM2 = 1, no slave will be interrupted by a data byte. An address byte, however, will interrupt all slaves, so that each slave can examine the received byte and see if it is being addressed. The addressed slave will clear its SM2 bit and prepare to receive the data bytes that will be coming. 2003 May 14 (Oscillator Frequency) n = 32 in 12-clock mode, 16 in 6-clock mode One can achieve very low baud rates with Timer 1 by leaving the Timer 1 interrupt enabled, and configuring the Timer to run as a 16-bit timer (high nibble of TMOD = 0001B), and using the Timer 1 interrupt to do a 16-bit software reload. Figure 8 lists various commonly used baud rates and how they can be obtained from Timer 1. 19 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) SCON Address = 98H Bit Addressable Reset Value = 00H 7 6 5 4 3 2 1 0 SM0 SM1 SM2 REN TB8 RB8 TI RI Where SM0, SM1 specify the serial port mode, as follows: SM0 0 0 1 1 SM1 0 1 0 1 Mode 0 1 2 3 Description shift register 8-bit UART 9-bit UART 9-bit UART Baud Rate fOSC/12 (12-clock mode) or fOSC/6 (6-clock mode) variable fOSC/64 or fOSC/32 (12-clock mode) or fOSC/32 or fOSC/16 (6-clock mode) variable SM2 Enables the multiprocessor communication feature in Modes 2 and 3. In Mode 2 or 3, if SM2 is set to 1, then Rl will not be activated if the received 9th data bit (RB8) is 0. In Mode 1, if SM2=1 then RI will not be activated if a valid stop bit was not received. In Mode 0, SM2 should be 0. REN Enables serial reception. Set by software to enable reception. Clear by software to disable reception. TB8 The 9th data bit that will be transmitted in Modes 2 and 3. Set or clear by software as desired. RB8 In Modes 2 and 3, is the 9th data bit that was received. In Mode 1, it SM2=0, RB8 is the stop bit that was received. In Mode 0, RB8 is not used. TI Transmit interrupt flag. 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, in any serial transmission. Must be cleared by software. RI Receive interrupt flag. Set by hardware at the end of the 8th bit time in Mode 0, or halfway through the stop bit time in the other modes, in any serial reception (except see SM2). Must be cleared by software. SU01626 Figure 7. Serial Port Control (SCON) Register Timer 1 Baud Rate Mode 12-clock mode 6-clock mode Mode 0 Max Mode 2 Max Mode 1, 3 Max Mode 1, 3 1.67 MHz 625 k 104.2 k 19.2 k 9.6 k 4.8 k 2.4 k 1.2 k 137.5 110 110 3.34 MHz 1250 k 208.4 k 38.4 k 19.2 k 9.6 k 4.8 k 2.4 k 275 220 220 fOSC SMOD 20 MHz 20 MHz 20 MHz 11.059 MHz 11.059 MHz 11.059 MHz 11.059 MHz 11.059 MHz 11.986 MHz 6 MHz 12 MHz X 1 1 1 0 0 0 0 0 0 0 C/T Mode Reload Value X X 0 0 0 0 0 0 0 0 0 X X 2 2 2 2 2 2 2 2 1 X X FFH FDH FDH FAH F4H E8H 1DH 72H FEEBH Figure 8. Timer 1 Generated Commonly Used Baud Rates More About Mode 0 Serial data enters and exits through RxD. TxD outputs the shift clock. 8 bits are transmitted/received: 8 data bits (LSB first). The baud rate is fixed a 1/12 the oscillator frequency (12-clock mode) or 1/6 the oscillator frequency (6-clock mode). S6P2 of every machine cycle in which SEND is active, the contents of the transmit shift are shifted to the right one position. As data bits shift out to the right, zeros come in from the left. When the MSB of the data byte is at the output position of the shift register, then the 1 that was initially loaded into the 9th position, is just to the left of the MSB, and all positions to the left of that contain zeros. This condition flags the TX Control block to do one last shift and then deactivate SEND and set T1. Both of these actions occur at S1P1 of the 10th machine cycle after “write to SBUF.” Figure 9 shows a simplified functional diagram of the serial port in Mode 0, and associated timing. Transmission is initiated by any instruction that uses SBUF as a destination register. The “write to SBUF” signal at S6P2 also loads a 1 into the 9th position of the transmit shift register and tells the TX Control block to commence a transmission. The internal timing is such that one full machine cycle will elapse between “write to SBUF” and activation of SEND. Reception is initiated by the condition REN = 1 and R1 = 0. At S6P2 of the next machine cycle, the RX Control unit writes the bits 11111110 to the receive shift register, and in the next clock phase activates RECEIVE. RECEIVE enable SHIFT CLOCK to the alternate output function line of P3.1. SHIFT CLOCK makes transitions at S3P1 and S6P1 of every machine cycle. At S6P2 of every machine cycle in which RECEIVE is active, the contents of the receive shift register are SEND enables the output of the shift register to the alternate output function line of P3.0 and also enable SHIFT CLOCK to the alternate output function line of P3.1. SHIFT CLOCK is low during S3, S4, and S5 of every machine cycle, and high during S6, S1, and S2. At 2003 May 14 20 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) shifted to the left one position. The value that comes in from the right is the value that was sampled at the P3.0 pin at S5P2 of the same machine cycle. whether the above conditions are met or not, the unit goes back to looking for a 1-to-0 transition in RxD. More About Modes 2 and 3 Eleven bits are transmitted (through TxD), or received (through RxD): a start bit (0), 8 data bits (LSB first), a programmable 9th data bit, and a stop bit (1). On transmit, the 9th data bit (TB8) can be assigned the value of 0 or 1. On receive, the 9the data bit goes into RB8 in SCON. The baud rate is programmable to either 1/32 or 1/64 (12-clock mode) or 1/16 or 1/32 the oscillator frequency (6-clock mode) the oscillator frequency in Mode 2. Mode 3 may have a variable baud rate generated from Timer 1 or Timer 2. As data bits come in from the right, 1s shift out to the left. When the 0 that was initially loaded into the rightmost position arrives at the leftmost position in the shift register, it flags the RX Control block to do one last shift and load SBUF. At S1P1 of the 10th machine cycle after the write to SCON that cleared RI, RECEIVE is cleared as RI is set. More About Mode 1 Ten bits are transmitted (through TxD), or received (through RxD): a start bit (0), 8 data bits (LSB first), and a stop bit (1). On receive, the stop bit goes into RB8 in SCON. In the 80C51 the baud rate is determined by the Timer 1 or Timer 2 overflow rate. Figures 11 and 12 show a functional diagram of the serial port in Modes 2 and 3. The receive portion is exactly the same as in Mode 1. The transmit portion differs from Mode 1 only in the 9th bit of the transmit shift register. Figure 10 shows a simplified functional diagram of the serial port in Mode 1, and associated timings for transmit receive. Transmission is initiated by any instruction that uses SBUF as a destination register. The “write to SBUF” signal also loads TB8 into the 9th bit position of the transmit shift register and flags the TX Control unit that a transmission is requested. Transmission commences at S1P1 of the machine cycle following the next rollover in the divide-by-16 counter. (Thus, the bit times are synchronized to the divide-by-16 counter, not to the “write to SBUF” signal.) Transmission is initiated by any instruction that uses SBUF as a destination register. The “write to SBUF” signal also loads a 1 into the 9th bit position of the transmit shift register and flags the TX Control unit that a transmission is requested. Transmission actually commences at S1P1 of the machine cycle following the next rollover in the divide-by-16 counter. (Thus, the bit times are synchronized to the divide-by-16 counter, not to the “write to SBUF” signal.) The transmission begins with activation of SEND, which puts the start bit at TxD. One bit time later, DATA is activated, which enables the output bit of the transmit shift register to TxD. The first shift pulse occurs one bit time after that. The first shift clocks a 1 (the stop bit) into the 9th bit position of the shift register. Thereafter, only zeros are clocked in. Thus, as data bits shift out to the right, zeros are clocked in from the left. When TB8 is at the output position of the shift register, then the stop bit is just to the left of TB8, and all positions to the left of that contain zeros. This condition flags the TX Control unit to do one last shift and then deactivate SEND and set TI. This occurs at the 11th divide-by-16 rollover after “write to SUBF.” The transmission begins with activation of SEND which puts the start bit at TxD. One bit time later, DATA is activated, which enables the output bit of the transmit shift register to TxD. The first shift pulse occurs one bit time after that. As data bits shift out to the right, zeros are clocked in from the left. When the MSB of the data byte is at the output position of the shift register, then the 1 that was initially loaded into the 9th position is just to the left of the MSB, and all positions to the left of that contain zeros. This condition flags the TX Control unit to do one last shift and then deactivate SEND and set TI. This occurs at the 10th divide-by-16 rollover after “write to SBUF.” Reception is initiated by a detected 1-to-0 transition at RxD. For this purpose RxD is sampled at a rate of 16 times whatever baud rate has been established. When a transition is detected, the divide-by-16 counter is immediately reset, and 1FFH is written to the input shift register. Reception is initiated by a detected 1-to-0 transition at RxD. For this purpose RxD is sampled at a rate of 16 times whatever baud rate has been established. When a transition is detected, the divide-by-16 counter is immediately reset, and 1FFH is written into the input shift register. Resetting the divide-by-16 counter aligns its rollovers with the boundaries of the incoming bit times. At the 7th, 8th, and 9th counter states of each bit time, the bit detector samples the value of R-D. The value accepted is the value that was seen in at least 2 of the 3 samples. If the value accepted during the first bit time is not 0, the receive circuits are reset and the unit goes back to looking for another 1-to-0 transition. If the start bit proves valid, it is shifted into the input shift register, and reception of the rest of the frame will proceed. The 16 states of the counter divide each bit time into 16ths. At the 7th, 8th, and 9th counter states of each bit time, the bit detector samples the value of RxD. The value accepted is the value that was seen in at least 2 of the 3 samples. This is done for noise rejection. If the value accepted during the first bit time is not 0, the receive circuits are reset and the unit goes back to looking for another 1-to-0 transition. This is to provide rejection of false start bits. If the start bit proves valid, it is shifted into the input shift register, and reception of the rest of the frame will proceed. As data bits come in from the right, 1s shift out to the left. When the start bit arrives at the leftmost position in the shift register (which in Modes 2 and 3 is a 9-bit register), it flags the RX Control block to do one last shift, load SBUF and RB8, and set RI. The signal to load SBUF and RB8, and to set RI, will be generated if, and only if, the following conditions are met at the time the final shift pulse is generated. 1. RI = 0, and 2. Either SM2 = 0, or the received 9th data bit = 1. As data bits come in from the right, 1s shift out to the left. When the start bit arrives at the leftmost position in the shift register (which in mode 1 is a 9-bit register), it flags the RX Control block to do one last shift, load SBUF and RB8, and set RI. The signal to load SBUF and RB8, and to set RI, will be generated if, and only if, the following conditions are met at the time the final shift pulse is generated.: 1. R1 = 0, and 2. Either SM2 = 0, or the received stop bit = 1. If either of these conditions is not met, the received frame is irretrievably lost, and RI is not set. If both conditions are met, the received 9th data bit goes into RB8, and the first 8 data bits go into SBUF. One bit time later, whether the above conditions were met or not, the unit goes back to looking for a 1-to-0 transition at the RxD input. If either of these two conditions is not met, the received frame is irretrievably lost. If both conditions are met, the stop bit goes into RB8, the 8 data bits go into SBUF, and RI is activated. At this time, 2003 May 14 21 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) 80C51 Internal Bus Write to SBUF S D Q RxD P3.0 Alt Output Function SBUF CL Zero Detector Start Shift TX Control S6 T1 TX Clock Send Serial Port Interrupt R1 RX Clock Receive RX Control REN RI Start 1 1 1 TxD P3.1 Alt Output Function Shift Clock Shift 1 1 1 1 0 MSB LSB RxD P3.0 Alt Input Function Input Shift Register Shift Load SBUF LSB MSB SBUF Read SBUF 80C51 Internal Bus S4 . . S1 . . . . S6 S1 . . . . S6 S1 . . . . S6 S1 . . . . S6 S1 . . . . S6 S1 . . . . S6 S1 . . . . S6 S1 . . . . S6 S1 . . . . S6 S1 . . . . S6 S1 ALE Write to SBUF S6P2 Send Shift Transmit RxD (Data Out) D0 D1 D2 D3 D4 D5 D6 D7 TxD (Shift Clock) S3P1 TI S6P1 Write to SCON (Clear RI) RI Receive Shift RxD (Data In) Receive D0 D1 D2 D3 D4 D5 D6 D7 S5P2 TxD (Shift Clock) SU00539 Figure 9. Serial Port Mode 0 2003 May 14 22 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) Timer 1 Overflow 80C51 Internal Bus TB8 ÷2 SMOD = 0 SMOD = 1 Write to SBUF S D Q SBUF TxD CL Zero Detector Start Data Shift TX Control ÷ 16 T1 Send RX Clock RI Load SBUF TX Clock Serial Port Interrupt ÷ 16 Sample RX Control 1-to-0 Transition Detector Shift Start 1FFH Bit Detector Input Shift Register (9 Bits) Shift RxD Load SBUF SBUF Read SBUF 80C51 Internal Bus TX Clock Write to SBUF Send Data S1P1 Transmit Shift TxD Start Bit D0 D1 D2 D3 D4 D5 D6 D7 Stop Bit D0 D1 D2 D3 D4 D5 D6 D7 Stop Bit TI ÷ 16 Reset RX Clock RxD Bit Detector Sample Times Start Bit Receive Shift RI SU00540 Figure 10. Serial Port Mode 1 2003 May 14 23 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) 80C51 Internal Bus TB8 Write to SBUF S D Phase 2 Clock (1/2 fOSC in 12-clock mode; fOSC in 6-clock mode) Q SBUF TxD CL Zero Detector Mode 2 Start ÷ 16 SMOD = 1 Stop Bit Gen. TX Control TX Clock Shift Data T1 Send R1 Load SBUF Serial Port Interrupt ÷2 SMOD = 0 (SMOD is PCON.7) ÷ 16 RX Clock Sample RX Control 1-to-0 Transition Detector Shift Start 1FFH Bit Detector Input Shift Register (9 Bits) Shift RxD Load SBUF SBUF Read SBUF 80C51 Internal Bus TX Clock Write to SBUF Send Data S1P1 Transmit Shift TxD Start Bit D0 D1 D2 D3 D4 D5 D6 D7 TB8 D0 D1 D2 D3 D4 D5 D6 D7 RB8 Stop Bit TI Stop Bit Gen. ÷ 16 Reset RX Clock RxD Bit Detector Sample Times Start Bit Stop Bit Receive Shift RI SU01627 Figure 11. Serial Port Mode 2 2003 May 14 24 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) Timer 1 Overflow 80C51 Internal Bus TB8 Write to SBUF ÷2 SMOD = 0 SMOD = 1 S D Q SBUF TxD CL Zero Detector Start Data Shift TX Control ÷ 16 TX Clock T1 Send R1 Load SBUF Serial Port Interrupt ÷ 16 RX Clock Sample RX Control 1-to-0 Transition Detector Shift Start 1FFH Bit Detector Input Shift Register (9 Bits) Shift RxD Load SBUF SBUF Read SBUF 80C51 Internal Bus TX Clock Write to SBUF Send Data S1P1 Transmit Shift TxD Start Bit D0 D1 D2 D3 D4 D5 D6 D7 TB8 D0 D1 D2 D3 D4 D5 D6 D7 RB8 Stop Bit TI Stop Bit Gen. RX Clock RxD Bit Detector Sample Times ÷ 16 Reset Start Bit Stop Bit Receive Shift RI SU00542 Figure 12. Serial Port Mode 3 2003 May 14 25 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) Enhanced UART Slave 0 The UART operates in all of the usual modes that are described in the first section of Data Handbook IC20, 80C51-Based 8-Bit Microcontrollers. In addition the UART can perform framing error detect by looking for missing stop bits, and automatic address recognition. The P87CL5xX2 UART also fully supports multiprocessor communication. SADDR SADEN Given = = = 1100 0000 1111 1101 1100 00X0 Slave 1 SADDR SADEN Given = = = 1100 0000 1111 1110 1100 000X In the above example SADDR is the same and the SADEN data is used to differentiate between the two slaves. Slave 0 requires a 0 in bit 0 and it ignores bit 1. Slave 1 requires a 0 in bit 1 and bit 0 is ignored. A unique address for Slave 0 would be 1100 0010 since slave 1 requires a 0 in bit 1. A unique address for slave 1 would be 1100 0001 since a 1 in bit 0 will exclude slave 0. Both slaves can be selected at the same time by an address which has bit 0 = 0 (for slave 0) and bit 1 = 0 (for slave 1). Thus, both could be addressed with 1100 0000. When used for framing error detect the UART looks for missing stop bits in the communication. A missing bit will set the FE bit in the SCON register. The FE bit shares the SCON.7 bit with SM0 and the function of SCON.7 is determined by PCON.6 (SMOD0) (see Figure 13). If SMOD0 is set then SCON.7 functions as FE. SCON.7 functions as SM0 when SMOD0 is cleared. When used as FE SCON.7 can only be cleared by software. Refer to Figure 14. Automatic Address Recognition Automatic Address Recognition is a feature which allows the UART to recognize certain addresses in the serial bit stream by using hardware to make the comparisons. This feature saves a great deal of software overhead by eliminating the need for the software to examine every serial address which passes by the serial port. This feature is enabled by setting the SM2 bit in SCON. In the 9 bit UART modes, mode 2 and mode 3, the Receive Interrupt flag (RI) will be automatically set when the received byte contains either the “Given” address or the “Broadcast” address. The 9 bit mode requires that the 9th information bit is a 1 to indicate that the received information is an address and not data. Automatic address recognition is shown in Figure 15. In a more complex system the following could be used to select slaves 1 and 2 while excluding slave 0: The 8 bit mode is called Mode 1. In this mode the RI flag will be set if SM2 is enabled and the information received has a valid stop bit following the 8 address bits and the information is either a Given or Broadcast address. SADDR SADEN Given = = = 1100 0000 1111 1001 1100 0XX0 Slave 1 SADDR SADEN Given = = = 1110 0000 1111 1010 1110 0X0X Slave 2 SADDR SADEN Given = = = 1110 0000 1111 1100 1110 00XX In the above example the differentiation among the 3 slaves is in the lower 3 address bits. Slave 0 requires that bit 0 = 0 and it can be uniquely addressed by 1110 0110. Slave 1 requires that bit 1 = 0 and it can be uniquely addressed by 1110 and 0101. Slave 2 requires that bit 2 = 0 and its unique address is 1110 0011. To select Slaves 0 and 1 and exclude Slave 2 use address 1110 0100, since it is necessary to make bit 2 = 1 to exclude slave 2. Mode 0 is the Shift Register mode and SM2 is ignored. Using the Automatic Address Recognition feature allows a master to selectively communicate with one or more slaves by invoking the Given slave address or addresses. All of the slaves may be contacted by using the Broadcast address. Two special Function Registers are used to define the slave’s address, SADDR, and the address mask, SADEN. SADEN is used to define which bits in the SADDR are to b used and which bits are “don’t care”. The SADEN mask can be logically ANDed with the SADDR to create the “Given” address which the master will use for addressing each of the slaves. Use of the Given address allows multiple slaves to be recognized while excluding others. The following examples will help to show the versatility of this scheme: 2003 May 14 Slave 0 The Broadcast Address for each slave is created by taking the logical OR of SADDR and SADEN. Zeros in this result are trended as don’t-cares. In most cases, interpreting the don’t-cares as ones, the broadcast address will be FF hexadecimal. Upon reset SADDR (SFR address 0A9H) and SADEN (SFR address 0B9H) are leaded with 0s. This produces a given address of all “don’t cares” as well as a Broadcast address of all “don’t cares”. This effectively disables the Automatic Addressing mode and allows the microcontroller to use standard 80C51 type UART drivers which do not make use of this feature. 26 Philips Semiconductors Product data 80C51 8-bit microcontroller family 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) P87CL52X2/54X2 SCON Address = 98H Reset Value = 0000 0000B Bit Addressable SM0/FE Bit: SM1 7 6 (SMOD0 = 0/1)* SM2 REN TB8 RB8 Tl Rl 5 4 3 2 1 0 Symbol Function FE Framing Error bit. This bit is set by the receiver when an invalid stop bit is detected. The FE bit is not cleared by valid frames but should be cleared by software. The SMOD0 bit must be set to enable access to the FE bit. SM0 Serial Port Mode Bit 0, (SMOD0 must = 0 to access bit SM0) SM1 Serial Port Mode Bit 1 SM0 SM1 Mode 0 0 1 1 0 1 0 1 0 1 2 3 Description Baud Rate** shift register 8-bit UART 9-bit UART 9-bit UART fOSC/12 variable fOSC/64 or fOSC/32 variable SM2 Enables the Automatic Address Recognition feature in Modes 2 or 3. If SM2 = 1 then Rl will not be set unless the received 9th data bit (RB8) is 1, indicating an address, and the received byte is a Given or Broadcast Address. In Mode 1, if SM2 = 1 then Rl will not be activated unless a valid stop bit was received, and the received byte is a Given or Broadcast Address. In Mode 0, SM2 should be 0. REN Enables serial reception. Set by software to enable reception. Clear by software to disable reception. TB8 The 9th data bit that will be transmitted in Modes 2 and 3. Set or clear by software as desired. RB8 In modes 2 and 3, the 9th data bit that was received. In Mode 1, if SM2 = 0, RB8 is the stop bit that was received. In Mode 0, RB8 is not used. Tl Transmit interrupt flag. 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, in any serial transmission. Must be cleared by software. Rl Receive interrupt flag. Set by hardware at the end of the 8th bit time in Mode 0, or halfway through the stop bit time in the other modes, in any serial reception (except see SM2). Must be cleared by software. NOTE: *SMOD0 is located at PCON6. **fOSC = oscillator frequency SU00043 Figure 13. SCON: Serial Port Control Register 2003 May 14 27 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) D0 D1 D2 D3 D4 D5 D6 D7 D8 DATA BYTE START BIT ONLY IN MODE 2, 3 STOP BIT SET FE BIT IF STOP BIT IS 0 (FRAMING ERROR) SM0 TO UART MODE CONTROL SM0 / FE SM1 SM2 REN SMOD1 SMOD0 – POF TB8 GF1 RB8 TI GF0 PD RI SCON (98H) IDL PCON (87H) 0 : SCON.7 = SM0 1 : SCON.7 = FE SU01191 Figure 14. UART Framing Error Detection D0 D1 D2 D3 D4 SM0 SM1 1 1 1 0 D5 SM2 1 D6 D7 D8 REN TB8 RB8 1 X TI RI SCON (98H) RECEIVED ADDRESS D0 TO D7 COMPARATOR PROGRAMMED ADDRESS IN UART MODE 2 OR MODE 3 AND SM2 = 1: INTERRUPT IF REN=1, RB8=1 AND “RECEIVED ADDRESS” = “PROGRAMMED ADDRESS” – WHEN OWN ADDRESS RECEIVED, CLEAR SM2 TO RECEIVE DATA BYTES – WHEN ALL DATA BYTES HAVE BEEN RECEIVED: SET SM2 TO WAIT FOR NEXT ADDRESS. SU00045 Figure 15. UART Multiprocessor Communication, Automatic Address Recognition 2003 May 14 28 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) An interrupt will be serviced as long as an interrupt of equal or higher priority is not already being serviced. If an interrupt of equal or higher level priority is being serviced, the new interrupt will wait until it is finished before being serviced. If a lower priority level interrupt is being serviced, it will be stopped and the new interrupt serviced. When the new interrupt is finished, the lower priority level interrupt that was stopped will be completed. Interrupt Priority Structure The P87CL5xX2 has a 6-source four-level interrupt structure. They are the IE, IP and IPH. (See Figures 16, 17, and 18.) The IPH (Interrupt Priority High) register that makes the four-level interrupt structure possible. The IPH is located at SFR address B7H. The structure of the IPH register and a description of its bits is shown in Figure 18. The function of the IPH SFR is simple and when combined with the IP SFR determines the priority of each interrupt. The priority of each interrupt is determined as shown in the following table: PRIORITY BITS INTERRUPT PRIORITY LEVEL IPH.x IP.x 0 0 Level 0 (lowest priority) 0 1 Level 1 1 0 Level 2 1 1 Level 3 (highest priority) Table 7. Interrupt Table SOURCE POLLING PRIORITY REQUEST BITS HARDWARE CLEAR? N (L)1 Y (T)2 VECTOR ADDRESS X0 1 IE0 T0 2 TP0 Y 03H X1 3 IE1 N (L) Y (T) 13H T1 4 TF1 Y 1BH SP 5 RI, TI N 23H T2 6 TF2, EXF2 N 2BH 0BH NOTES: 1. L = Level activated 2. T = Transition activated IE (0A8H) 7 6 5 4 3 2 1 0 EA — ET2 ES ET1 EX1 ET0 EX0 Enable Bit = 1 enables the interrupt. Enable Bit = 0 disables it. BIT IE.7 SYMBOL EA IE.6 IE.5 IE.4 IE.3 IE.2 IE.1 IE.0 — ET2 ES ET1 EX1 ET0 EX0 FUNCTION Global disable bit. If EA = 0, all interrupts are disabled. If EA = 1, each interrupt can be individually enabled or disabled by setting or clearing its enable bit. Not implemented. Reserved for future use. Timer 2 interrupt enable bit. Serial Port interrupt enable bit. Timer 1 interrupt enable bit. External interrupt 1 enable bit. Timer 0 interrupt enable bit. External interrupt 0 enable bit. SU00571 Figure 16. IE Registers 2003 May 14 29 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) IP (0B8H) 7 6 5 4 3 2 1 0 — — PT2 PS PT1 PX1 PT0 PX0 Priority Bit = 1 assigns higher priority Priority Bit = 0 assigns lower priority BIT IP.7 IP.6 IP.5 IP.4 IP.3 IP.2 IP.1 IP.0 SYMBOL — — PT2 PS PT1 PX1 PT0 PX0 FUNCTION Not implemented, reserved for future use. Not implemented, reserved for future use. Timer 2 interrupt priority bit. Serial Port interrupt priority bit. Timer 1 interrupt priority bit. External interrupt 1 priority bit. Timer 0 interrupt priority bit. External interrupt 0 priority bit. SU00572 Figure 17. IP Registers IPH (B7H) 7 6 5 4 3 2 1 0 — — PT2H PSH PT1H PX1H PT0H PX0H Priority Bit = 1 assigns higher priority Priority Bit = 0 assigns lower priority BIT IPH.7 IPH.6 IPH.5 IPH.4 IPH.3 IPH.2 IPH.1 IPH.0 SYMBOL — — PT2H PSH PT1H PX1H PT0H PX0H FUNCTION Not implemented, reserved for future use. Not implemented, reserved for future use. Timer 2 interrupt priority bit high. Serial Port interrupt priority bit high. Timer 1 interrupt priority bit high. External interrupt 1 priority bit high. Timer 0 interrupt priority bit high. External interrupt 0 priority bit high. Figure 18. IPH Registers 2003 May 14 30 SU01058 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) Note that bit 2 is not writable and is always read as a zero. This allows the DPS bit to be quickly toggled simply by executing an INC DPTR instruction without affecting the WOPD or LPEP bits. Reduced EMI Mode The AO bit (AUXR.0) in the AUXR register when set disables the ALE output. Reduced EMI Mode AUXR (8EH) DPS 7 6 5 4 3 2 1 0 – – – – – – – AO AUXR.0 AO BIT0 AUXR1 DPTR1 DPTR0 Turns off ALE output. DPH (83H) DPL (82H) EXTERNAL DATA MEMORY Dual DPTR SU00745A The dual DPTR structure (see Figure 19) enables a way to specify the address of an external data memory location. There are two 16-bit DPTR registers that address the external memory, and a single bit called DPS = AUXR1/bit0 that allows the program code to switch between them. Figure 19. DPTR Instructions The instructions that refer to DPTR refer to the data pointer that is currently selected using the AUXR1/bit 0 register. The six instructions that use the DPTR are as follows: • New Register Name: AUXR1# • SFR Address: A2H • Reset Value: xxx000x0B INC DPTR AUXR1 (A2H) 7 6 5 4 3 2 1 0 – – – – WUPD 0 – DPS Where: DPS = AUXR1/bit0 = Switches between DPTR0 and DPTR1. Select Reg DPS DPTR0 0 DPTR1 1 MOV DPTR, #data16 Loads the DPTR with a 16-bit constant MOV A, @ A+DPTR Move code byte relative to DPTR to ACC MOVX A, @ DPTR Move external RAM (16-bit address) to ACC MOVX @ DPTR , A Move ACC to external RAM (16-bit address) JMP @ A + DPTR Jump indirect relative to DPTR The data pointer can be accessed on a byte-by-byte basis by specifying the low or high byte in an instruction which accesses the SFRs. See application note AN458 for more details. The DPS bit status should be saved by software when switching between DPTR0 and DPTR1. 2003 May 14 Increments the data pointer by 1 31 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) ABSOLUTE MAXIMUM RATINGS1, 2, 3 PARAMETER 0 to +70 °C °C 0 to +13.0 V Voltage on EA pin to VSS Voltage on any other pin to VSS UNIT –65 to +150 Operating temperature under bias Storage temperature range RATING –0.5 to +6.5 V 15 mA Maximum IOL per I/O pin Power dissipation (based on package heat transfer limitations, not device power consumption) 1.5 W NOTES: 1. Stresses 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 conditions other than those described in the AC and DC Electrical Characteristics section of this specification is not implied. 2. This product includes circuitry specifically designed for the protection of its internal devices from the damaging effects of excessive static charge. Nonetheless, it is suggested that conventional precautions be taken to avoid applying greater than the rated maximum. 3. Parameters are valid over operating temperature range unless otherwise specified. All voltages are with respect to VSS unless otherwise noted. AC ELECTRICAL CHARACTERISTICS Tamb = 0 °C to +70 °C or –40 °C to +85 °C CLOCK FREQUENCY RANGE –f SYMBOL 1/tCLCL 2003 May 14 FIGURE 29 PARAMETER Oscillator frequency Operating mode: 6-clock 12-clock 32 MIN MAX 0 0 16 33 UNIT MHz MHz Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) DC ELECTRICAL CHARACTERISTICS Tamb = 0 °C to +70 °C, VCC = 1.8 V to 3.3 V, VSS = 0 V (12 MHz devices) SYMBOL TEST CONDITIONS PARAMETER VIL Input low voltage VIH Input high voltage (ports 0, 1, 2, 3, EA) VIH1 Input high voltage, XTAL1, RST 36 VOL Output low voltage, ports 1, 2, VOL1 Output low voltage, port 0, ALE, PSEN6, 5 3 LIMITS MIN TYP1 MAX UNIT –0.5 0.2 VCC – 0.05 V 0.35 VCC + 0.55 VCC+0.5 V 0.7 VCC VCC+0.5 V IOL = 1.6 mA – 0.3 V IOL = 3.2 mA – 0.4 V IOH = –30 µA VCC – 0.6 – V VCC = 1.8 V IOH = –3.2 mA VCC – 0.7 – V VOH Output high voltage, ports 1, 2, 3 VOH1 Output high voltage (port 0 in external bus mode), ALE7, PSEN3 IIL Logical 0 input current, ports 1, 2, 3 VIN = 0.4 V – –40 µA ITL Logical 1-to-0 transition current, ports 1, 2, 3 VIN = 1.25 V VDD = 3.3 V – –300 µA ILI Input leakage current, port 0 0.45 V < VIN < VCC – 0.3 V – –10 µA ICC Power supply current (see Figure 27): Active mode @ 1.8 V VCC / 1 MHz Active mode @ 1.8 V VCC / 12 MHz Active mode @ 3.3 V VCC / 12 MHz Idle mode @ 1.8 V VCC 1 MHz Idle mode @ 1.8 V VCC 12 MHz Idle mode @ 3.3 V VCC 12 MHz Power-down mode (see Figure 32 for conditions) 0.4 1.5 3.7 0.24 0.68 0.68 2 mA mA mA mA mA mA µA 225 kΩ RRST See note 4 Tamb = 0 °C to 70 °C Internal reset pull-down resistor – – – – – – – 40 0.15 1.35 2.70 0.1 0.25 0.5 1 CIO Pin capacitance8 (except EA) – 15 pF NOTES: 1. Typical ratings are not guaranteed. The values listed are at room temperature. 2. Capacitive loading on ports 0 and 2 may cause spurious noise 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 operations. In such cases, it may be desirable to qualify ALE with a Schmitt Trigger, or use an address latch with a Schmitt Trigger STROBE input. IOL can exceed these conditions provided that no single output sinks more than 5 mA and no more than two outputs exceed the test conditions. 3. Capacitive loading on ports 0 and 2 may cause the VOH on ALE and PSEN to momentarily fall below the VCC–0.7 V specification when the address bits are stabilizing. 4. See Figures 29 through 32 for ICC test conditions. Active mode: ICC = fclk *0.1 mA/MHz + 0.3 mA (1.8 V). See Figure 27 Active mode: ICC = fclk *0.25 mA/MHz + 0.7 mA (3.3 V) Idle mode: ICCI = fclk *0.04 mA/MHz + 0.2 mA 5. Load capacitance for port 0, ALE, and PSEN = 100 pF, load capacitance for all other outputs = 80 pF. 6. Under steady state (non-transient) conditions, IOL must be externally limited as follows: 10 mA Maximum IOL per port pin: Maximum IOL per 8-bit port: 20 mA 40 mA Maximum total IOL for all outputs: 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. ALE is tested to VOH1, except when ALE is off then VOH is the voltage specification. 8. Pin capacitance is characterized but not tested. Pin capacitance is less than 15 pF. 2003 May 14 33 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) DC ELECTRICAL CHARACTERISTICS Tamb = 0 °C to +70 °C, VCC = 3.3 V ",10%, VSS = 0 V (33 MHz devices) SYMBOL TEST CONDITIONS PARAMETER VIL Input low voltage VIH Input high voltage (ports 0, 1, 2, 3, EA) VIH1 Input high voltage, XTAL1, RST 36 VOL Output low voltage, ports 1, 2, VOL1 Output low voltage, port 0, ALE, PSEN6, 5 3 LIMITS MIN TYP1 MAX UNIT –0.5 0.2 VCC – 0.05 V 0.35 VCC + 0.55 VCC+0.5 V 0.7 VCC VCC+0.5 V IOL = 1.6 mA – 0.3 V IOL = 3.2 mA – 0.4 V IOH = –30 µA VCC – 0.6 – V IOH = –3.2 mA VCC – 0.7 – V VOH Output high voltage, ports 1, 2, 3 VOH1 Output high voltage (port 0 in external bus mode), ALE7, PSEN3 IIL Logical 0 input current, ports 1, 2, 3 VIN = 0.4 V – –40 µA ITL Logical 1-to-0 transition current, ports 1, 2, 3 VIN = 1.25 V VDD = 3.3 V – –300 µA ILI Input leakage current, port 0 0.45 V < VIN < VCC – 0.3 V – –10 µA ICC Power supply current (see Figure 27): Active mode @ 33 MHz Idle mode @ 33 MHz Power-down mode (see Figure 32 for conditions) 10.6 2 2 mA mA µA 225 kΩ RRST See note 4 Tamb = 0 °C to 70 °C Internal reset pull-down resistor – – – 40 capacitance8 7.6 1.5 t1 CIO Pin (except EA) – 15 pF NOTES: 1. Typical ratings are not guaranteed. The values listed are at room temperature. 2. Capacitive loading on ports 0 and 2 may cause spurious noise 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 operations. In such cases, it may be desirable to qualify ALE with a Schmitt Trigger, or use an address latch with a Schmitt Trigger STROBE input. IOL can exceed these conditions provided that no single output sinks more than 5 mA and no more than two outputs exceed the test conditions. 3. Capacitive loading on ports 0 and 2 may cause the VOH on ALE and PSEN to momentarily fall below the VCC–0.7 V specification when the address bits are stabilizing. 4. See Figures 29 through 32 for ICC test conditions. Active mode: ICC = fclk *0.3 mA/MHz + 0.7 mA. See Figure 27 Idle mode: ICCI = fclk *0.045 mA/MHz + 0.5 mA 5. Load capacitance for port 0, ALE, and PSEN = 100 pF, load capacitance for all other outputs = 80 pF. 6. Under steady state (non-transient) conditions, IOL must be externally limited as follows: 10 mA Maximum IOL per port pin: 20 mA Maximum IOL per 8-bit port: Maximum total IOL for all outputs: 40 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. ALE is tested to VOH1, except when ALE is off then VOH is the voltage specification. 8. Pin capacitance is characterized but not tested. Pin capacitance is less than 15 pF. 2003 May 14 34 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) AC ELECTRICAL CHARACTERISTICS Tamb = 0 °C to +70 °C, VCC = +1.8 V to +3.3 V, VSS = 0 V1, 2, 3 12 MHz CLOCK SYMBOL FIGURE PARAMETER MIN MAX VARIABLE CLOCK MIN MAX UNIT 1.0 12 MHz 1/tCLCL 14 Oscillator frequency4 tLHLL 20 ALE pulse width 85 2tCLCL–40 ns tAVLL 20 Address valid to ALE low 22 tCLCL–40 ns tLLAX 20 Address hold after ALE low 32 tCLCL–30 tLLIV 20 ALE low to valid instruction in tLLPL 20 ALE low to PSEN low 32 tCLCL–30 tPLPH 20 PSEN pulse width 142 3tCLCL–45 tPLIV 20 PSEN low to valid instruction in tPXIX 20 Input instruction hold after PSEN tPXIZ 20 Input instruction float after PSEN 37 tCLCL–25 ns tAVIV 20 Address to valid instruction in 207 5tCLCL–105 ns tPLAZ 20 PSEN low to address float 10 10 ns 150 82 0 ns 4tCLCL–100 ns ns ns 3tCLCL–105 0 ns ns Data Memory tRLRH 21, 22 RD pulse width 275 6tCLCL–100 tWLWH 21, 22 WR pulse width 275 6tCLCL–100 tRLDV 21, 22 RD low to valid data in tRHDX 21, 22 Data hold after RD tRHDZ 21, 22 Data float after RD 65 2tCLCL–60 ns tLLDV 21, 22 ALE low to valid data in 350 8tCLCL–150 ns tAVDV 21, 22 Address to valid data in 397 9tCLCL–165 ns tLLWL 21, 22 ALE low to RD or WR low 137 3tCLCL+50 ns tAVWL 21, 22 Address valid to WR low or RD low 122 4tCLCL–130 ns tQVWX 21, 22 Data valid to WR transition 13 tCLCL–50 ns tWHQX 21, 22 Data hold after WR 13 tCLCL–50 ns tQVWH 22 Data valid to WR high 287 7tCLCL–150 tRLAZ 21, 22 RD low to address float tWHLH 21, 22 RD or WR high to ALE high 23 147 0 ns ns 5tCLCL–165 0 239 3tCLCL–50 0 103 tCLCL–40 ns ns ns 0 ns tCLCL+40 ns External Clock tCHCX 24 High time 20 20 tCLCL–tCLCX ns tCLCX 24 Low time 20 20 tCLCL–tCHCX ns tCLCH 24 Rise time 20 20 ns tCHCL 24 Fall time 20 20 ns tXLXL 23 Serial port clock cycle time 750 12tCLCL ns tQVXH 23 Output data setup to clock rising edge 492 10tCLCL–133 ns tXHQX 23 Output data hold after clock rising edge 8 2tCLCL–117 ns tXHDX 23 Input data hold after clock rising edge 0 0 ns Shift Register tXHDV 23 Clock rising edge to input data valid 668 10tCLCL–165 ns NOTES: 1. Parameters are valid over operating temperature range unless otherwise specified. 2. Load capacitance for port 0, ALE, and PSEN = 100 pF, load capacitance for all other outputs = 80 pF. 3. Interfacing the P87CL5xX2 to devices with float times up to 45 ns is permitted. This limited bus contention will not cause damage to Port 0 drivers. 4. Parts are guaranteed to operate down to 0 Hz. When an external clock source is used, the RST pin should be held high for a minimum of 20 µs for power-on or wakeup from power down. 2003 May 14 35 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) AC ELECTRICAL CHARACTERISTICS Tamb = 0 °C to +70 °C VCC = 3.3 V ±10%, VSS = 0 V1, 2, 3 VARIABLE CLOCK4 33 MHz CLOCK 12 MHz to fmax SYMBOL FIGURE PARAMETER MIN MAX MIN MAX UNIT tLHLL 20 ALE pulse width 2tCLCL–40 21 ns tAVLL 20 Address valid to ALE low tCLCL–25 5 ns tLLAX 20 Address hold after ALE low tCLCL–25 tLLIV 20 ALE low to valid instruction in tLLPL 20 ALE low to PSEN low tCLCL–25 5 ns tPLPH 20 PSEN pulse width 3tCLCL–45 45 ns tPLIV 20 PSEN low to valid instruction in tPXIX 20 Input instruction hold after PSEN tPXIZ 20 Input instruction float after PSEN tCLCL–25 5 ns tAVIV 20 Address to valid instruction in 5tCLCL–80 70 ns tPLAZ 20 PSEN low to address float 10 10 ns ns 4tCLCL–65 55 3tCLCL–60 0 30 0 ns ns ns Data Memory tRLRH 21, 22 RD pulse width 6tCLCL–100 82 tWLWH 21, 22 WR pulse width 6tCLCL–100 82 tRLDV 21, 22 RD low to valid data in tRHDX 21, 22 Data hold after RD tRHDZ 21, 22 Data float after RD 2tCLCL–28 32 ns tLLDV 21, 22 ALE low to valid data in 8tCLCL–150 90 ns tAVDV 21, 22 Address to valid data in 9tCLCL–165 105 ns tLLWL 21, 22 ALE low to RD or WR low 3tCLCL–50 140 ns tAVWL 21, 22 Address valid to WR low or RD low 4tCLCL–75 45 ns tQVWX 21, 22 Data valid to WR transition tCLCL–30 0 ns tWHQX 21, 22 Data hold after WR tCLCL–25 5 ns tQVWH 22 7tCLCL–130 80 tRLAZ 21, 22 RD low to address float tWHLH 21, 22 RD or WR high to ALE high tCLCL–25 5tCLCL–90 0 Data valid to WR high ns ns 60 0 3tCLCL+50 40 0 tCLCL+25 5 ns ns ns 0 ns 55 ns External Clock tCHCX 24 High time 0.38tCLCL tCLCL–tCLCX ns tCLCX 24 Low time 0.38tCLCL tCLCL–tCHCX ns tCLCH 24 Rise time 5 ns tCHCL 24 Fall time 5 ns tXLXL 23 Serial port clock cycle time 12tCLCL 360 ns tQVXH 23 Output data setup to clock rising edge 10tCLCL–133 167 ns tXHQX 23 Output data hold after clock rising edge 2tCLCL–80 tXHDX 23 Input data hold after clock rising edge Shift Register 0 ns 0 ns tXHDV 23 Clock rising edge to input data valid 10tCLCL–165 138 ns NOTES: 1. Parameters are valid over operating temperature range unless otherwise specified. 2. Load capacitance for port 0, ALE, and PSEN = 100 pF, load capacitance for all other outputs = 80 pF. 3. Interfacing the P87CL5xX2 to devices with float times up to 45ns is permitted. This limited bus contention will not cause damage to Port 0 drivers. 4. Variable clock is specified for oscillator frequencies greater than 12 MHz to 33 MHz. For frequencies equal or less than 12 MHz, see 12 MHz “AC Electrical Characteristics”, page 35. 5. Parts are guaranteed to operate down to 0 Hz. When an external clock source is used, the RST pin should be held high for a minimum of 20 µs for power-on or wakeup from power down. 2003 May 14 36 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) EXPLANATION OF THE AC SYMBOLS P – PSEN Q – Output data R – RD signal t – Time V – Valid W – WR signal X – No longer a valid logic level Z – Float Examples: tAVLL = Time for address valid to ALE low. tLLPL = Time for ALE low to PSEN low. Each timing symbol has five characters. The first character is always ‘t’ ( = time). The other characters, depending on their positions, indicate the name of a signal or the logical status of that signal. The designations are: A – Address C – Clock D – Input data H – Logic level high I – Instruction (program memory contents) L – Logic level low, or ALE tLHLL ALE tAVLL tLLPL tPLPH tLLIV tPLIV PSEN tLLAX INSTR IN A0–A7 PORT 0 tPXIZ tPLAZ tPXIX A0–A7 tAVIV PORT 2 A0–A15 A8–A15 SU00006 Figure 20. External Program Memory Read Cycle ALE tWHLH PSEN tLLDV tLLWL tRLRH RD tAVLL tLLAX tRLAZ PORT 0 tRHDZ tRLDV tRHDX A0–A7 FROM RI OR DPL DATA IN A0–A7 FROM PCL INSTR IN tAVWL tAVDV PORT 2 P2.0–P2.7 OR A8–A15 FROM DPF A0–A15 FROM PCH SU00025 Figure 21. External Data Memory Read Cycle 2003 May 14 37 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) ALE tWHLH PSEN tWLWH tLLWL WR tLLAX tAVLL tWHQX tQVWX tQVWH A0–A7 FROM RI OR DPL PORT 0 DATA OUT A0–A7 FROM PCL INSTR IN tAVWL PORT 2 P2.0–P2.7 OR A8–A15 FROM DPF A0–A15 FROM PCH SU00026 Figure 22. External Data Memory Write Cycle INSTRUCTION 0 1 2 3 4 5 6 7 8 ALE tXLXL CLOCK tXHQX tQVXH OUTPUT DATA 0 1 2 WRITE TO SBUF 3 4 5 6 7 tXHDX tXHDV SET TI INPUT DATA VALID VALID VALID VALID VALID VALID VALID VALID CLEAR RI SET RI SU00027 Figure 23. Shift Register Mode Timing VCC–0.5 0.45V 0.7VCC 0.2VCC–0.1 tCHCL tCHCX tCLCH tCLCX tCLCL SU00009 Figure 24. External Clock Drive 2003 May 14 38 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) TBD VLOAD+0.1V TBD TIMING REFERENCE POINTS VLOAD TBD VLOAD–0.1V TBD SU01726 SU00718 Figure 25. AC Testing Input/Output Figure 26. Float Waveform 1.6 MAX ACTIVE MODE 1.4 TYP ACTIVE MODE ICC(mA) 1.2 1.0 0.8 MAX IDLE MODE 0.6 0.4 TYP IDLE MODE 0.2 0 2 4 6 8 10 12 14 FREQ AT XTAL1 (MHz) SU01757 Figure 27. ICC vs. FREQ (1.8 V) Valid only within frequency specifications of the device under test 12 MAX ACTIVE MODE 10 ICC(mA) 8 TYP ACTIVE MODE 6 4 MAX IDLE MODE 2 TYP IDLE MODE 0 0 5 10 15 20 25 30 35 FREQ AT XTAL1 (MHz) SU01758 Figure 28. ICC vs. FREQ (3.3 V) Valid only within frequency specifications of the device under test 2003 May 14 VOL+0.1V NOTE: For timing purposes, a port is no longer floating when a 100mV change from load voltage occurs, and begins to float when a 100mV change from the loaded VOH/VOL level occurs. IOH/IOL ≥ ±20mA. NOTE: AC inputs during testing are driven at VCC –0.5 for a logic ‘1’ and 0.45V for a logic ‘0’. Timing measurements are made at VIH min for a logic ‘1’ and VIL max for a logic ‘0’. 0 VOH–0.1V 39 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) VCC VCC ICC ICC VCC VCC VCC VCC RST RST P0 P0 EA EA (NC) XTAL2 (NC) XTAL2 CLOCK SIGNAL XTAL1 CLOCK SIGNAL XTAL1 VSS VSS SU00719 SU00720 Figure 29. ICC Test Condition, Active Mode All other pins are disconnected VCC–0.5 Figure 30. ICC Test Condition, Idle Mode All other pins are disconnected 0.7VCC 0.2VCC–0.1 0.45V tCHCL tCHCX tCLCH tCLCX tCLCL SU00009 Figure 31. Clock Signal Waveform for ICC Tests in Active and Idle Modes tCLCH = tCHCL = 5ns VCC ICC VCC VCC RST P0 EA (NC) XTAL2 XTAL1 VSS SU00016 Figure 32. ICC Test Condition, Power Down Mode All other pins are disconnected. VCC = TBD 2003 May 14 VCC 40 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) device. The VPP source should be well regulated and free of glitches and overshoot. EPROM CHARACTERISTICS The OTP devices described in this data sheet can be programmed by using a modified Improved Quick-Pulse Programming algorithm. It differs from older methods in the value used for VPP (programming supply voltage) and in the width and number of the ALE/PROG pulses. The family contains two signature bytes that can be read and used by an EPROM programming system to identify the device. The signature bytes identify the device as being manufactured by Philips. Program Verification If security bits 2 and 3 have not been programmed, the on-chip program memory can be read out for program verification. The address of the program memory locations to be read is applied to ports 1 and 2 as shown in Figure 35. The other pins are held at the ‘Verify Code Data’ levels indicated in Table 8. The contents of the address location will be emitted on port 0. External pull-ups are required on port 0 for this operation. Table 8 shows the logic levels for reading the signature byte, and for programming the program memory, the encryption table, and the security bits. The circuit configuration and waveforms for quick-pulse programming are shown in Figures 33 and 34. Figure 35 shows the circuit configuration for normal program memory verification. If the 64 byte encryption table has been programmed, the data presented at port 0 will be the exclusive NOR of the program byte with one of the encryption bytes. The user will have to know the encryption table contents in order to correctly decode the verification data. The encryption table itself cannot be read out. Quick-Pulse Programming Reading the Signature bytes The signature bytes are read by the same procedure as a normal verification of locations 030h and 031h, except that P3.6 and P3.7 need to be pulled to a logic low. The values are: (030h) = 15h; indicates manufacturer (Philips) (031h) = 92h — P87CL52X2 BBH — P87CL54X2 The setup for microcontroller quick-pulse programming is shown in Figure 33. Note that the device is running with a 4 to 6 MHz oscillator. The reason the oscillator needs to be running is that the device is executing internal address and program data transfers. The address of the EPROM location to be programmed is applied to ports 1 and 2, as shown in Figure 33. The code byte to be programmed into that location is applied to port 0. RST, PSEN and pins of ports 2 and 3 specified in Table 8 are held at the ‘Program Code Data’ levels indicated in Table 8. The ALE/PROG is pulsed low 5 times as shown in Figure 34. Program/Verify Algorithms Any algorithm in agreement with the conditions listed in Table 8, and which satisfies the timing specifications, is suitable. Security Bits To program the encryption table, repeat the 5 pulse programming sequence for addresses 0 through 1FH, using the ‘Pgm Encryption Table’ levels. Do not forget that after the encryption table is programmed, verification cycles will produce only encrypted data. With none of the security bits programmed the code in the program memory can be verified. If the encryption table is programmed, the code will be encrypted when verified. When only security bit 1 (see Table 9) is programmed, MOVC instructions executed from external program memory are disabled from fetching code bytes from the internal memory, EA is latched on Reset and all further programming of the EPROM is disabled. When security bits 1 and 2 are programmed, in addition to the above, verify mode is disabled. When all three security bits are programmed, all of the conditions above apply and all external program memory execution is disabled. To program the security bits, repeat the 5 pulse programming sequence using the ‘Pgm Security Bit’ levels. After one security bit is programmed, further programming of the code memory and encryption table is disabled. However, the other security bits can still be programmed. Note that the EA/VPP pin must not be allowed to go above the maximum specified VPP level for any amount of time. Even a narrow glitch above that voltage can cause permanent damage to the Encryption Array 64 bytes of encryption array are initially unprogrammed (all 1s). Trademark phrase of Intel Corporation. 2003 May 14 41 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) Table 8. EPROM Programming Modes RST PSEN ALE/PROG EA/VPP P2.7 P2.6 P3.7 P3.6 P3.3 Read signature MODE 1 0 1 1 0 0 0 0 X Program code data 1 0 0* VPP 1 0 1 1 X Verify code data 1 0 1 1 0 0 1 1 X Pgm encryption table 1 0 0* VPP 1 0 1 0 X Pgm security bit 1 1 0 0* VPP 1 1 1 1 X Pgm security bit 2 1 0 0* VPP 1 1 0 0 X Pgm security bit 3 1 0 0* VPP 0 1 0 1 X Program to 6-clock mode 1 0 0* VPP 0 0 1 0 0 Verify 6-clock4 1 0 1 1 e 0 0 1 1 Verify security bits5 1 0 1 1 e 0 1 0 X NOTES: 1. ‘0’ = Valid low for that pin, ‘1’ = valid high for that pin. 2. VPP = 12.75 V ±0.25 V. 3. VCC = 5 V±10% during programming and verification. 4. Bit is output on P0.4 (1 = 12x, 0 = 6x). 5. Security bit one is output on P0.7. Security bit two is output on P0.6. Security bit three is output on P0.3. * ALE/PROG receives 5 programming pulses for code data (also for user array; 5 pulses for encryption or security bits) while VPP is held at 12.75 V. Each programming pulse is low for 100 µs (±10 µs) and high for a minimum of 10 µs. Table 9. Program Security Bits for EPROM Devices PROGRAM LOCK BITS1, 2 SB1 SB2 SB3 PROTECTION DESCRIPTION 1 U U U No Program Security features enabled. (Code verify will still be encrypted by the Encryption Array if programmed.) 2 P U U MOVC instructions executed from external program memory are disabled from fetching code bytes from internal memory, EA is sampled and latched on Reset, and further programming of the EPROM is disabled. 3 P P U Same as 2, also verify is disabled. 4 P P P Same as 3, external execution is disabled. Internal data RAM is not accessible. NOTES: 1. P – programmed. U – unprogrammed. 2. Any other combination of the security bits is not defined. 2003 May 14 42 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) +5V A0–A7 VCC P1 P0 1 RST 1 P3.6 EA/VPP 1 P3.7 ALE/PROG OTP XTAL2 4–6MHz XTAL1 PGM DATA +12.75V 5 PULSES TO GROUND PSEN 0 P2.7 1 P2.6 0 A8–A12 P2.0–P2.5 VSS SU01488 Figure 33. Programming Configuration 5 PULSES 1 ALE/PROG: 0 1 2 3 4 5 SEE EXPLODED VIEW BELOW tGHGL = 10µs MIN tGLGH = 100µs±10µs 1 ALE/PROG: 1 0 SU00875 Figure 34. PROG Waveform +5V VCC A0–A7 P0 P1 1 RST 1 P3.6 1 P3.7 OTP XTAL2 4–6MHz XTAL1 PGM DATA EA/VPP 1 ALE/PROG 1 PSEN 0 P2.7 0 ENABLE P2.6 0 P2.0–P2.5 A8–A12 VSS SU01489 Figure 35. Program Verification 2003 May 14 43 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) PROGRAMMING AND VERIFICATION CHARACTERISTICS Tamb = 21 °C to +27 °C, VCC = 5 V±10%, VSS = 0 V (See Figure 36) SYMBOL PARAMETER MIN MAX UNIT 12.5 13.0 V 50 1 mA 6 MHz VPP Programming supply voltage IPP Programming supply current 1/tCLCL Oscillator frequency tAVGL Address setup to PROG low 48tCLCL tGHAX Address hold after PROG 48tCLCL tDVGL Data setup to PROG low 48tCLCL tGHDX Data hold after PROG 48tCLCL tEHSH P2.7 (ENABLE) high to VPP 48tCLCL tSHGL VPP setup to PROG low 10 µs tGHSL VPP hold after PROG 10 µs tGLGH PROG width 90 tAVQV Address to data valid 48tCLCL tELQZ ENABLE low to data valid 48tCLCL tEHQZ Data float after ENABLE 0 tGHGL PROG high to PROG low 10 4 110 µs 48tCLCL µs NOTE: 1. Not tested. PROGRAMMING* VERIFICATION* P1.0–P1.7 P2.0–P2.5 P3.4 (A0 – A12) ADDRESS ADDRESS PORT 0 P0.0 – P0.7 (D0 – D7) DATA IN tAVQV DATA OUT tDVGL tAVGL tGHDX tGHAX ALE/PROG tGLGH tSHGL tGHGL tGHSL LOGIC 1 LOGIC 1 EA/VPP LOGIC 0 tEHSH tELQV tEHQZ P2.7 ** SU01414 NOTES: * FOR PROGRAMMING CONFIGURATION SEE FIGURE 33. FOR VERIFICATION CONDITIONS SEE FIGURE 35. ** SEE TABLE 8. Figure 36. Programming and Verification 2003 May 14 44 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) TSSOP38: plastic thin shrink small outline package; 38 leads; body width 4.4 mm; lead pitch 0.5 mm 2003 May 14 45 SOT510-1 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) LQFP44: plastic low profile quad flat package; 44 leads; body 10 x 10 x 1.4 mm 2003 May 14 46 SOT389-1 Philips Semiconductors Product data 80C51 8-bit microcontroller family P87CL52X2/54X2 8K/16K OTP 256 bytes RAM ROMless low voltage (1.8 V to 3.3 V), low power, high speed (33 MHz) REVISION HISTORY Rev Date Description _2 20030514 Product data (9397 750 11515); ECN 853-2427 29875 of 29 April 2003 Modifications: • Change to Product data _1 20030430 Preliminary data (9397 750 11442) Data sheet status Level Data sheet status [1] Product status [2] [3] Definitions I Objective data Development This data sheet contains data from the objective specification for product development. Philips Semiconductors reserves the right to change the specification in any manner without notice. II Preliminary data Qualification This data sheet contains data from the preliminary specification. Supplementary data will be published at a later date. Philips Semiconductors reserves the right to change the specification without notice, in order to improve the design and supply the best possible product. III Product data Production This data sheet contains data from the product specification. Philips Semiconductors reserves the right to make changes at any time in order to improve the design, manufacturing and supply. Relevant changes will be communicated via a Customer Product/Process Change Notification (CPCN). [1] Please consult the most recently issued data sheet before initiating or completing a design. [2] The product status of the device(s) described in this data sheet may have changed since this data sheet was published. The latest information is available on the Internet at URL http://www.semiconductors.philips.com. [3] For data sheets describing multiple type numbers, the highest-level product status determines the data sheet status. Definitions Short-form specification — The data in a short-form specification is extracted from a full data sheet with the same type number and title. For detailed information see the relevant data sheet or data handbook. Limiting values definition — Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 60134). Stress above one or more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or at any other conditions above those given in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended periods may affect device reliability. Application information — Applications that are described herein for any of these products are for illustrative purposes only. Philips Semiconductors make no representation or warranty that such applications will be suitable for the specified use without further testing or modification. Disclaimers Life support — These products are not designed for use in life support appliances, devices, or systems where malfunction of these products can reasonably be expected to result in personal injury. Philips Semiconductors customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Philips Semiconductors for any damages resulting from such application. Right to make changes — Philips Semiconductors reserves the right to make changes in the products—including circuits, standard cells, and/or software—described or contained herein in order to improve design and/or performance. When the product is in full production (status ‘Production’), relevant changes will be communicated via a Customer Product/Process Change Notification (CPCN). Philips Semiconductors assumes no responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright, or mask work right to these products, and makes no representations or warranties that these products are free from patent, copyright, or mask work right infringement, unless otherwise specified. Koninklijke Philips Electronics N.V. 2003 All rights reserved. Printed in U.S.A. Contact information For additional information please visit http://www.semiconductors.philips.com. Fax: +31 40 27 24825 Date of release: 05-03 For sales offices addresses send e-mail to: [email protected]. Document order number: 2003 May 14 47 9397 750 11515