Datasheet P89C51RD+, P89C51RC+ Datasheet (Philips)

Download

Page 1

 

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

Product specification

Replaces 89C51RC+/RD+ of 1999 Apr 01

(see Notes 1 and 2 on page 2)

Supersedes data of 1999 Apr 01

IC28 Data Handbook

1999 Oct 27

INTEGRATED CIRCUITS

Page 2

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27 853-2149 22593

DESCRIPTION

The 89C51RX+ devices contain a non-volatile FLASH program memory (up to 64 k bytes in the 89C51RD+) that is both parallel programmable and Serial In-System Programmable. In-System Programming allows devices to alter their own program memory, in the actual end product, under software control. This opens up a range of applications that can include the ability to field update the application firmware.

A default serial loader (boot loader) program in ROM allows In-System serial programming of the FLASH memory without the need for a loader in the FLASH code. User programs may erase and reprogram the FLASH memory at will through the use of standard routines contained in ROM.

These devices are Single-Chip 8-Bit Microcontrollers manufactured in advanced CMOS process and are derivatives of the 80C51 microcontroller family. All the devices have the same instruction set as the 80C51.

FLASH/EPROM

Memory Size

(X by 8)

RAM Size

(X by 8)

Programmable

Timer Counter

(PCA)

89C51RC+

32 k 512 Yes

89C51RD+

64 k 1024 Yes

See P89C51RX2 data sheet for devices which do not require a 12 V programming voltage.

The devices also have four 8-bit I/O ports, three 16-bit timer/event counters, a multi-source, four-priority-level, nested interrupt structure, an enhanced UART and on-chip oscillator and timing circuits. For systems that require extra memory capability up to 64 k bytes, each can be expanded using standard TTL-compatible memories and logic.

The added features of the P89C51RX+ Family makes them even more powerful microcontrollers for applications that require pulse width modulation, high-speed I/O and up/down counting capabilities such as motor control.

FEA TURES

•80C51 Central Processing Unit

•On-chip FLASH Program Memory with In-System Programming

(ISP) capability

•Boot ROM contains low level FLASH programming routines and a

default serial loader

•Speed up to 33 MHz

•Full static operation

•RAM expandable externally to 64 k bytes

•4 level priority interrupt

•7 interrupt sources, depending on device

•Four 8-bit I/O ports

•Full-duplex enhanced UART

– Framing error detection – Automatic address recognition

•Power control modes

– Clock can be stopped and resumed – Idle mode – Power down mode

•Programmable clock out

•Second DPTR register

•Asynchronous port reset

•Low EMI (inhibit ALE)

•Watchdog timer

ORDERING INFORMATION

MEMORY SIZE

32 k × 8

MEMORY SIZE

64 k × 8

TEMPERATURE RANGE °C

AND PACKAGE

VOLTAGE

RANGE

FREQ.

(MHz)

DWG.

P89C51RC+IN P89C51RD+IN

0 to +70,

40-Pin Plastic Dual In-line Pkg.

5 V 0 to 33 SOT129-1

P89C51RC+IA P89C51RD+IA

0 to +70,

44-Pin Plastic Leaded Chip Carrier

5 V 0 to 33 SOT187-2

P89C51RC+IB P89C51RD+IB

0 to +70,

44-Pin Plastic Quad Flat Pack

5 V 0 to 33 QFP44

P89C51RC+JN P89C51RD+JN

–40 to +85,

40-Pin Plastic Dual In-line Pkg.

5 V 0 to 33 SOT129-1

P89C51RC+JA P89C51RD+JA

–40 to +85,

44-Pin Plastic Leaded Chip Carrier

5 V 0 to 33 SOT187-2

P89C51RC+JB P89C51RD+JB

–40 to +85,

44-Pin Plastic Quad Flat Pack

5 V 0 to 33 QFP44

NOTE:

1. SOT not assigned for this package outline.

Page 3

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

ORDERING INFORMATION

DEVICE NUMBER (P89C51RC+) TEMPERATURE RANGE/OPERATING

FREQUENCY, MAX (I)

PACKAGE (A)

P89C51RC+ (FLASH)

I = 33 MHz, 0_C to 70_C

A = PLCC

P89C51RD+ (FLASH)

J = 33 MHz, –40_C to +85_C

B = PQFP

N = PDIP

BLOCK DIAGRAM

SU01065

PSEN

EAV

ALE

RST

XTAL1 XTAL2

PORT 0

DRIVERS

PORT 2

DRIVERS

RAM ADDR REGISTER

RAM

PORT 0

LATCH

PORT 2

LATCH

FLASH

ACC

STACK

POINTER

TMP2

TMP1

ALU

TIMING

AND

CONTROL

INSTRUCTION

OSCILLATOR

PSW

PORT 1

LATCH

PORT 3

LATCH

PORT 1

DRIVERS

PORT 3

DRIVERS

PROGRAM ADDRESS REGISTER

BUFFER

INCRE-

MENTER

PROGRAM COUNTER

DPTR’S

MULTIPLE

P1.0–P1.7

P3.0–P3.7

P0.0–P0.7 P2.0–P2.7

SFRs

TIMERS

P.C.A.

8 16

Page 4

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

LOGIC SYMBOL

PORT 0

PORT 1PORT 2

PORT 3

ADDRESS AND

DATA BUS

ADDRESS BUS

T2 T2EX

RxD

TxD INT0 INT1

T0 T1

SECONDARY FUNCTIONS

RST

EA/V

PSEN

ALE/PROG

XTAL1

XTAL2

SU00830

PIN CONFIGURA TIONS

DUAL IN-LINE P ACKAGE PIN FUNCTIONS

SU00888

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16 17 18 19 20

T2/P1.0

T2EX/P1.1

ECI/P1.2 CEX0/P1.3 CEX1/P1.4 CEX2/P1.5 CEX3/P1.6

RST RxD/P3.0 TxD/P3.1

INT0

/P3.2

INT1

/P3.3 T0/P3.4 T1/P3.5

CEX4/P1.7

/P3.6 RD

/P3.7

XTAL2 XTAL1

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

P0.7/AD7

P0.6/AD6

P0.5/AD5

P0.4/AD4

P0.3/AD3

P0.2/AD2

P0.1/AD1

P0.0/AD0

DUAL

IN-LINE

PACKAGE

PLASTIC LEADED CHIP CARRIER PIN FUNCTIONS

SU00890

LCC

6140

18 28

Pin Function

1 NIC* 2 P1.0/T2 3 P1.1/T2EX 4 P1.2/ECI 5 P1.3/CEX0 6 P1.4/CEX1 7 P1.5/CEX2 8 P1.6/CEX3

9 P1.7/CEX4 10 RST 11 P3.0/RxD 12 NIC* 13 P3.1/TxD 14 P3.2/INT0 15 P3.3/INT1

Pin Function

16 P3.4/T0 17 P3.5/T1 18 P3.6/WR 19 P3.7/RD 20 XTAL2 21 XTAL1 22 V

23 NIC* 24 P2.0/A8 25 P2.1/A9 26 P2.2/A10 27 P2.3/A11 28 P2.4/A12 29 P2.5/A13 30 P2.6/A14

Pin Function

31 P2.7/A15 32 PSEN 33 ALE 34 NIC* 35 EA/V

36 P0.7/AD7 37 P0.6/AD6 38 P0.5/AD5 39 P0.4/AD4 40 P0.3/AD3 41 P0.2/AD2 42 P0.1/AD1 43 P0.0/AD0 44 V

* NO INTERNAL CONNECTION

PLASTIC QUAD FLAT PACK PIN FUNCTIONS

SU00891

PQFP

44 34

12 22

Pin Function

1 P1.5/CEX2 2 P1.6/CEX3 3 P1.7/CEX4 4 RST 5 P3.0/RxD 6 NIC* 7 P3.1/TxD 8 P3.2/INT0

9 P3.3/INT1 10 P3.4/T0 11 P3.5/T1 12 P3.6/WR 13 P3.7/RD 14 XTAL2 15 XTAL1

Pin Function

16 V

17 NIC* 18 P2.0/A8 19 P2.1/A9 20 P2.2/A10 21 P2.3/A11 22 P2.4/A12 23 P2.5/A13 24 P2.6/A14 25 P2.7/A15 26 PSEN 27 ALE 28 NIC* 29 EA

30 P0.7/AD7

Pin Function

31 P0.6/AD6 32 P0.5/AD5 33 P0.4/AD4 34 P0.3/AD3 35 P0.2/AD2 36 P0.1/AD1 37 P0.0/AD0 38 V

39 NIC* 40 P1.0/T2 41 P1.1/T2EX 42 P1.2/ECI 43 P1.3/CEX0 44 P1.4/CEX1

* NO INTERNAL CONNECTION

Page 5

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

PIN DESCRIPTIONS

PIN NUMBER

MNEMONIC DIP LCC QFP TYPE NAME AND FUNCTION

20 22 16 I Ground: 0 V reference.

40 44 38 I Power Supply: This is the power supply voltage for normal, idle, and power-down operation.

P0.0–0.7 39–32 43–36 37–30 I/O Port 0: Port 0 is an open-drain, bidirectional I/O port. 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 1–8 2–9 40–44,

1–3

I/O Port 1: Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. 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: I

Alternate functions for 89C51RX+ Port 1 include: 1 2 40 I/O T2 (P1.0): T imer/Counter 2 external count input/Clockout (see Programmable Clock-Out) 2 3 41 I T2EX (P1.1): Timer/Counter 2 Reload/Capture/Direction Control 3 4 42 I ECI (P1.2): External Clock Input to the PCA 4 5 43 I/O CEX0 (P1.3): Capture/Compare External I/O for PCA module 0 5 6 44 I/O CEX1 (P1.4): Capture/Compare External I/O for PCA module 1 6 7 1 I/O CEX2 (P1.5): Capture/Compare External I/O for PCA module 2 7 8 2 I/O CEX3 (P1.6): Capture/Compare External I/O for PCA module 3 8 9 3 I/O CEX4 (P1.7): Capture/Compare External I/O for PCA module 4

P2.0–P2.7 21–28 24–31 18–25 I/O Port 2: Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. 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: I

). 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 10–17 11,

13–195,7–13

I/O Port 3: Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. 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: I

). Port 3 also serves the special features of the

89C51RX+ family , as listed below:

10 11 5 I RxD (P3.0): Serial input port 11 13 7 O TxD (P3.1): Serial output port 12 14 8 I INT0 (P3.2): External interrupt 13 15 9 I INT1 (P3.3): External interrupt 14 16 10 I T0 (P3.4): Timer 0 external input 15 17 11 I T1 (P3.5): Timer 1 external input 16 18 12 O WR (P3.6): External data memory write strobe 17 19 13 O RD (P3.7): External data memory read strobe

RST 9 10 4 I Reset: A high on this pin for two machine cycles while the oscillator is running, resets the

device. An internal resistor to V

permits a power-on reset using only an external capacitor

to V

ALE 30 33 27 O 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.

Page 6

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

PIN DESCRIPTIONS (Continued)

PIN NUMBER

MNEMONIC DIP LCC QFP TYPE NAME AND FUNCTION

PSEN 29 32 26 O Program Store Enable: The read strobe to external program memory. When 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/V

31 35 29 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 and 7FFFH. If EA

is held high, the device executes from internal program memory unless the program counter contains an address greater than 7FFFH for 32 k devices. The value on the EA

pin is latched when RST is released and any subsequent changes have no effect. Since the RD+ has 64 k internal memory, the RD+ will execute only from internal memory when EA

is held high. This pin also receives the 12.00 V programming supply voltage (VPP)

during FLASH programming.

XTAL1 19 21 15 I Crystal 1: Input to the inverting oscillator amplifier and input to the internal clock generator

circuits.

XTAL2 18 20 14 O Crystal 2: Output from the inverting oscillator amplifier .

NOTE:

To avoid “latch-up” effect at power-on, the voltage on any pin (other than V

) at any time must not be higher than VCC + 0.5 V or VSS – 0.5 V,

respectively.

Page 7

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

Table 1. Special Function Registers

SYMBOL DESCRIPTION

DIRECT

ADDRESS

BIT ADDRESS, SYMBOL, OR ALTERNATIVE PORT FUNCTION MSB LSB

RESET VALUE

ACC* Accumulator E0H E7 E6 E5 E4 E3 E2 E1 E0 00H AUXR# Auxiliary 8EH – – – – – –

EXTRAM

AO xxxxxx00B

AUXR1#2Auxiliary 1 A2H – –

ENBOOT

– GF2 0 – DPS xx0x00x0B B* B register F0H F7 F6 F5 F4 F3 F2 F1 F0 00H CCAP0H# Module 0 Capture High FAH xxxxxxxxB

CCAP1H# Module 1 Capture High FBH xxxxxxxxB CCAP2H# Module 2 Capture High FCH xxxxxxxxB CCAP3H# Module 3 Capture High FDH xxxxxxxxB CCAP4H# Module 4 Capture High FEH xxxxxxxxB CCAP0L# Module 0 Capture Low EAH xxxxxxxxB CCAP1L# Module 1 Capture Low EBH xxxxxxxxB CCAP2L# Module 2 Capture Low ECH xxxxxxxxB CCAP3L# Module 3 Capture Low EDH xxxxxxxxB CCAP4L# Module 4 Capture Low EEH xxxxxxxxB

CCAPM0# Module 0 Mode DAH – ECOM CAPP CAPN MAT TOG PWM ECCF x0000000B CCAPM1# Module 1 Mode DBH – ECOM CAPP CAPN MAT TOG PWM ECCF x0000000B CCAPM2# Module 2 Mode DCH – ECOM CAPP CAPN MAT TOG PWM ECCF x0000000B CCAPM3# Module 3 Mode DDH – ECOM CAPP CAPN MAT TOG PWM ECCF x0000000B CCAPM4# Module 4 Mode DEH – ECOM CAPP CAPN MAT TOG PWM ECCF x0000000B

DF DE DD DC DB DA D9 D8

CCON*# PCA Counter Control D8H CF CR – CCF4 CCF3 CCF2 CCF1 CCF0 00x00000B CH# PCA Counter High F9H 00H CL# PCA Counter Low E9H 00H

CMOD# PCA Counter Mode D9H CIDL WDTE – – – CPS1 CPS0 ECF 00xxx000B DPTR: Data Pointer (2 bytes)

DPH Data Pointer High 83H 00H DPL Data Pointer Low 82H 00H

AF AE AD AC AB AA A9 A8

IE* Interrupt Enable A8H EA EC ET2 ES ET1 EX1 ET0 EX0 00H

BF BE BD BC BB BA B9 B8

IP* Interrupt Priority B8H – PPC PT2 PS PT1 PX1 PT0 PX0 x0000000B

B7 B6 B5 B4 B3 B2 B1 B0

IPH# Interrupt Priority High B7H – PPCH PT2H PSH PT1H PX1H PT0H PX0H x0000000B

87 86 85 84 83 82 81 80

P0* Port 0 80H AD7 AD6 AD5 AD4 AD3 AD2 AD1 AD0 FFH

97 96 95 94 93 92 91 90

P1* Port 1 90H CEX4 CEX3 CEX2 CEX1 CEX0 ECI T2EX T2 FFH

A7 A6 A5 A4 A3 A2 A1 A0

P2* Port 2 A0H AD15 AD14 AD13 AD12 AD11 AD10 AD9 AD8 FFH

B7 B6 B5 B4 B3 B2 B1 B0

P3* Port 3 B0H RD WR T1 T0 INT1 INT0 TxD RxD FFH

PCON#1Power Control 87H SMOD1 SMOD0 – POF GF1 GF0 PD IDL 00xxx000B

* SFRs are bit addressable. # SFRs are modified from or added to the 80C51 SFRs. – Reserved bits.

1. Reset value depends on reset source.

2. The state of the ENBOOT bit depends on the status byte and PSEN

when reset is exited. See the AUXR1 description on page 20.

Page 8

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

Table 1. 89C51RC+/RD+ Special Function Registers (Continued)

SYMBOL DESCRIPTION

DIRECT

ADDRESS

BIT ADDRESS, SYMBOL, OR ALTERNATIVE PORT FUNCTION MSB LSB

RESET VALUE

D7 D6 D5 D4 D3 D2 D1 D0

PSW* Program Status Word D0H CY AC F0 RS1 RS0 OV – P 000000x0B

RACAP2H# Timer 2 Capture High CBH 00H RACAP2L# T imer 2 Capture Low CAH 00H

SADDR# Slave Address A9H 00H SADEN# Slave Address Mask B9H 00H

SBUF Serial Data Buffer 99H xxxxxxxxB

9F 9E 9D 9C 9B 9A 99 98

SCON* Serial Control 98H

SM0/FE

SM1 SM2 REN TB8 RB8 TI RI 00H

SP Stack Pointer 81H 07H

8F 8E 8D 8C 8B 8A 89 88

TCON* Timer Control 88H TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0 00H

CF CE CD CC CB CA C9 C8 T2CON* Timer 2 Control C8H TF2 EXF2 RCLK TCLK EXEN2 TR2 C/T2 CP/RL2 00H T2MOD# Timer 2 Mode Control C9H – – – – – – T2OE DCEN xxxxxx00B

TH0 Timer High 0 8CH 00H TH1 Timer High 1 8DH 00H TH2# Timer High 2 CDH 00H TL0 Timer Low 0 8AH 00H TL1 Timer Low 1 8BH 00H TL2# Timer Low 2 CCH 00H

TMOD Timer Mode 89H GATE C/T M1 M0 GATE C/T M1 M0 00H WDTRST Watchdog Timer Reset A6H

* SFRs are bit addressable. # SFRs are modified from or added to the 80C51 SFRs. – Reserved bits.

OSCILLA T OR 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.

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.

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-on 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. At power-on, the voltage on V

and RST must come up at the same time for a proper start-up. Ports 1, 2, and 3 will asynchronously be driven to their reset condition when a voltage above V

IH1

(min.) is applied to RESET.

The value on the EA

pin is latched when RST is deasserted and has

no further effect.

Page 9

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

LOW POWER MODES 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.

Idle Mode

In the 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.

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 the instruction that invoked Power Down is the last instruction executed. The on-chip RAM and Special Function Registers retain their values down to 2.0V and care must be taken to return V

to the minimum specified operating voltages before the Power Down Mode is terminated.

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.

To properly terminate Power Down the reset or external interrupt should not be executed before V

is restored to its normal operating level and must be held active long enough for the oscillator to restart and stabilize (normally less than 10ms).

With an external interrupt, INT0 and 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.

POWER OFF FLAG

The Power Off Flag (POF) is set by on-chip circuitry when the V

level on the 89C51RX+ rises from 0 to 5V. The POF bit can be set or cleared by software allowing a user to determine if the reset is the result of a power-on or a warm start after powerdown. The V

level must remain above 3V for the POF to remain unaffected by the V

level.

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.

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:

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 device 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.

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.

To configure the Timer/Counter 2 as a clock generator, bit C/T

2 (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.

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:

Oscillator Frequency

4 (65536 * RCAP2H,RCAP2L)

Where (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.

Table 2. External Pin Status During Idle and Power-Down Mode

MODE PROGRAM MEMORY ALE PSEN PORT 0 PORT 1 PORT 2 PORT 3

Idle 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

Page 10

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

TIMER 2 OPERA TION 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/T

2* 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.

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/T

2* 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.).

Auto-Reload Mode (Up or Down Counter)

In the 16-bit auto-reload mode, Timer 2 can be configured (as either a timer or counter [C/T

2* 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

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.

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 T imer 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.

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.

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.

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.

(MSB) (LSB)

Symbol Position Name and Significance

TF2 T2CON.7 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.

EXF2 T2CON.6 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).

RCLK T2CON.5 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.

TCLK T2CON.4 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.

EXEN2 T2CON.3 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. TR2 T2CON.2 Start/stop control for Timer 2. A logic 1 starts the timer. C/T2

T2CON.1 Timer or counter select. (T imer 2)

0 = Internal timer (OSC/12) 1 = External event counter (falling edge triggered).

CP/RL2

T2CON.0 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 .

TF2 EXF2 RCLK TCLK EXEN2 TR2 C/T2

CP/RL2

SU00728

Figure 1. Timer/Counter 2 (T2CON) Control Register

Page 11

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

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)

OSC

÷ 12

C/T2

= 0

C/T2

= 1

TR2

Control

TL2

(8-bits)

TH2

(8-bits)

TF2

RCAP2L RCAP2H

EXEN2

Control

EXF2

Timer 2

Interrupt

T2EX Pin

Transition

Detector

T2 Pin

Capture

SU00066

Figure 2. Timer 2 in Capture Mode

Not Bit Addressable

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.

— — — — — — T2OE DCEN

SU00729

76543210

* 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.

Bit

T2MOD Address = 0C9H Reset Value = XXXX XX00B

Figure 3. Timer 2 Mode (T2MOD) Control Register

Page 12

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

OSC

÷ 12

C/T2 = 0

C/T2

= 1

TR2

CONTROL

TL2

(8-BITS)

TH2

(8-BITS)

TF2

RCAP2L RCAP2H

EXEN2

CONTROL

EXF2

TIMER 2

INTERRUPT

T2EX PIN

TRANSITION

DETECTOR

T2 PIN

RELOAD

SU00067

Figure 4. Timer 2 in Auto-Reload Mode (DCEN = 0)

÷12

C/T2 = 0

C/T2

= 1

TL2 TH2

TR2

CONTROL

T2 PIN

SU00730

FFH FFH

RCAP2L RCAP2H

(UP COUNTING RELOAD VALUE) T2EX PIN

TF2

INTERRUPT

COUNT DIRECTION 1 = UP 0 = DOWN

EXF2

OVERFLOW

(DOWN COUNTING RELOAD VALUE)

TOGGLE

OSC

Figure 5. Timer 2 Auto Reload Mode (DCEN = 1)

Page 13

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

OSC

÷ 2

C/T2 = 0

C/T2

= 1

TR2

Control

TL2

(8-bits)

TH2

(8-bits)

÷ 16

RCAP2L RCAP2H

EXEN2

Control

EXF2

Timer 2 Interrupt

T2EX Pin

Transition

Detector

T2 Pin

Reload

NOTE: OSC. Freq. is divided by 2, not 12.

÷ 2

“0” “1”

RX Clock

÷ 16 TX Clock

“0”“1”

Timer 1

Overflow

Note availability of additional external interrupt.

SMOD

RCLK

TCLK

SU00068

Figure 6. Timer 2 in Baud Rate Generator Mode

T able 4. Timer 2 Generated Commonly Used

Baud Rates

Timer 2

Baud Rate

Osc Freq

RCAP2H RCAP2L

375 K 12 MHz FF FF

9.6 K 12 MHz FF D9

2.8 K 12 MHz FF B2

2.4 K 12 MHz FF 64

1.2 K 12 MHz FE C8 300 12 MHz FB 1E 110 12 MHz F2 AF 300 6 MHz FD 8F 110 6 MHz F9 57

Baud Rate Generator Mode

Bits TCLK and/or RCLK in T2CON (Table 4) 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.

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.

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

The timer can be configured for either “timer” or “counter” operation. In many applications, it is configured for “timer” operation (C/T

2*=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:

Oscillator Frequency

[32 [65536 * (RCAP2H,RCAP2L)]]

Modes 1 and 3 Baud Rates =

Where: (RCAP2H, RCAP2L)= The content of RCAP2H and RCAP2L taken as a 16-bit unsigned integer.

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.

Page 14

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

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, T imer 2 is incremented every state time (osc/2) or asynchronously from pin T2; 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.

Table 4 shows commonly used baud rates and how they can be obtained from Timer 2.

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

If Timer 2 is being clocked internally , the baud rate is:

Baud Rate +

OSC

[32 [65536 * (RCAP2H,RCAP2L)]]

Where f

OSC

= Oscillator Frequency

To obtain the reload value for RCAP2H and RCAP2L, the above equation can be rewritten as:

RCAP2H,RCAP2L + 65536 *

OSC

32 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.

Table 5. Timer 2 as a Timer

T2CON

MODE

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

TMOD

MODE

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.

Page 15

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

Enhanced UART

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 UART also fully supports multiprocessor communication as does the standard 80C51 UART.

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 7). 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 8.

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 9.

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.

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:

Slave 0 SADDR = 1100 0000

SADEN = 1111 1101 Given = 1100 00X0

Slave 1 SADDR = 1100 0000

SADEN = 1111 1110 Given = 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.

In a more complex system the following could be used to select slaves 1 and 2 while excluding slave 0:

Slave 0 SADDR = 1100 0000

SADEN = 1111 1001 Given = 1 100 0XX0

Slave 1 SADDR = 1110 0000

SADEN = 1111 1010 Given = 1 110 0X0X

Slave 2 SADDR = 1110 0000

SADEN = 1111 1100 Given = 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 01 10. 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.

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.

Page 16

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

SCON Address = 98H

Reset Value = 0000 0000B

SM0/FE SM1 SM2 REN TB8 RB8 Tl Rl

Bit Addressable

(SMOD0 = 0/1)*

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 Description Baud Rate**

0 0 0 shift register f

OSC

/12 0 1 1 8-bit UART variable 1 0 2 9-bit UART f

OSC

/64 or f

OSC

/32

1 1 3 9-bit UART 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. **f

OSC

= oscillator frequency

SU00043

Bit: 76543210

Figure 7. SCON: Serial Port Control Register

Page 17

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

SMOD1 SMOD0 – POF GF1 GF0 PD IDL

PCON

(87H)

SM0 / FE SM1 SM2 REN TB8 RB8 TI RI

SCON

(98H)

D0 D1 D2 D3 D4 D5 D6 D7 D8

STOP

BIT

DATA BYTE

ONLY IN

MODE 2, 3

START

BIT

SET FE BIT IF STOP BIT IS 0 (FRAMING ERROR)

SM0 TO UART MODE CONTROL

0 : SCON.7 = SM0 1 : SCON.7 = FE

SU01191

Figure 8. UART Framing Error Detection

SM0 SM1 SM2 REN TB8 RB8 TI RI

SCON

(98H)

D0 D1 D2 D3 D4 D5 D6 D7 D8

1 1

1 0

COMPARATOR

11 X

RECEIVED ADDRESS D0 TO D7

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 9. UART Multiprocessor Communication, Automatic Address Recognition

Page 18

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

Interrupt Priority Structure

The 89C51RC+/RD+ have a 7-source four-level interrupt structure (see Table 7).

There are 3 SFRs associated with the four-level interrupt. They are the IE, IP, and IPH. (See Figures 10, 11, and 12.) The IPH (Interrupt Priority High) register 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 12.

The function of the IPH SFR, 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

IPH.x IP.x

INTERRUPT PRIORITY LEVEL

0 0 Level 0 (lowest priority) 0 1 Level 1 1 0 Level 2 1 1 Level 3 (highest priority)

The priority scheme for servicing the interrupts is the same as that for the 80C51. There are four interrupt levels. 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.

Table 7. Interrupt Table

SOURCE POLLING PRIORITY REQUEST BITS HARDWARE CLEAR? VECTOR ADDRESS

X0 1 IE0 N (L)1Y (T)

03H

T0 2 TP0 Y 0BH

X1 3 IE1 N (L) Y (T) 13H

T1 4 TF1 Y 1BH

PCA 5 CF, CCFn

n = 0–4

N 33H

SP 6 RI, TI N 23H

T2 7 TF2, EXF2 N 2BH

NOTES:

1. L = Level activated

2. T = Transition activated

EX0IE (0A8H)

Enable Bit = 1 enables the interrupt. Enable Bit = 0 disables it.

BIT SYMBOL FUNCTION

IE.7 EA 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. IE.6 EC PCA interrupt enable bit IE.5 ET2 Timer 2 interrupt enable bit. IE.4 ES Serial Port interrupt enable bit. IE.3 ET1 Timer 1 interrupt enable bit. IE.2 EX1 External interrupt 1 enable bit. IE.1 ET0 Timer 0 interrupt enable bit. IE.0 EX0 External interrupt 0 enable bit.

SU01037

ET0EX1ET1ESET2ECEA

01234567

Figure 10. IE Registers

Page 19

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

PX0IP (0B8H)

Priority Bit = 1 assigns high priority Priority Bit = 0 assigns low priority

BIT SYMBOL FUNCTION

IP.7 — Not implemented, reserved for future use. IP.6 PPC PCA interrupt priority bit IP.5 PT2 Timer 2 interrupt priority bit. IP.4 PS Serial Port interrupt priority bit. IP.3 PT1 Timer 1 interrupt priority bit. IP.2 PX1 External interrupt 1 priority bit. IP.1 PT0 Timer 0 interrupt priority bit. IP.0 PX0 External interrupt 0 priority bit.

SU01038

PT0PX1PT1PSPT2PPC—

01234567

Figure 11. IP Registers

PX0HIPH (B7H)

Priority Bit = 1 assigns higher priority Priority Bit = 0 assigns lower priority

BIT SYMBOL FUNCTION

IPH.7 — Not implemented, reserved for future use. IPH.6 PPCH PCA interrupt priority bit IPH.5 PT2H Timer 2 interrupt priority bit high. IPH.4 PSH Serial Port interrupt priority bit high. IPH.3 PT1H Timer 1 interrupt priority bit high. IPH.2 PX1H External interrupt 1 priority bit high. IPH.1 PT0H Timer 0 interrupt priority bit high. IPH.0 PX0H External interrupt 0 priority bit high.

SU01039

PT0HPX1HPT1HPSHPT2HPPCH—

01234567

Figure 12. IPH Registers

Page 20

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

Reduced EMI Mode

The AO bit (AUXR.0) in the AUXR register when set disables the ALE output.

Reduced EMI Mode

AUXR (8EH)

765432 1 0 – – – – – – EXTRAM AO

AUXR.1 EXTRAM AUXR.0 AO Turns off ALE output.

Dual DPTR

The dual DPTR structure (see Figure 13) is a way by which the chip will 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.

•New Register Name: AUXR1#

•SFR Address: A2H

•Reset Value: xx0x00x0B

AUXR1 (A2H)

765 43210 –

– ENBOOT – GF2 0 – DPS

Where:

DPS = AUXR1/bit0 = Switches between DPTR0 and DPTR1.

Select Reg DPS

DPTR0 0 DPTR1 1

The DPS bit status should be saved by software when switching between DPTR0 and DPTR1.

The GF2 bit is a general purpose user-defined flag. 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 AUXR1 instruction without affecting the GF2 bit.

The ENBOOT bit determines whether the BOOTROM is enabled or disabled. This bit will automatically be set if the status byte is non zero during reset or PSEN

is pulled low, ALE floats high, and

EA > V

on the falling edge of reset. Otherwise, this bit will be

cleared during reset.

DPS

DPTR1 DPTR0

DPH

(83H)

DPL

(82H)

EXTERNAL

DATA

MEMORY

SU00745A

BIT0

AUXR1

Figure 13.

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:

INC DPTR Increments the data pointer by 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.

Page 21

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

Programmable Counter Array (PCA)

The Programmable Counter Array, available on the 89C51RX+, is a special 16-bit Timer that has five 16-bit capture/compare modules associated with it. Each of the modules can be programmed to operate in one of four modes: rising and/or falling edge capture, software timer, high-speed output, or pulse width modulator. Each module has a pin associated with it in port 1. Module 0 is connected to P1.3(CEX0), module 1 to P1.4(CEX1), etc. The basic PCA configuration is shown in Figure 14.

The PCA timer is a common time base for all five modules and can be programmed to run at: 1/12 the oscillator frequency, 1/4 the oscillator frequency , the Timer 0 overflow, or the input on the ECI pin (P1.2). The timer count source is determined from the CPS1 and CPS0 bits in the CMOD SFR as follows (see Figure 17):

CPS1 CPS0 PCA Timer Count Source

0 0 1/12 oscillator frequency 0 1 1/4 oscillator frequency 1 0 Timer 0 overflow 1 1 External Input at ECI pin

In the CMOD SFR are three additional bits associated with the PCA. They are CIDL which allows the PCA to stop during idle mode, WDTE which enables or disables the watchdog function on module 4, and ECF which when set causes an interrupt and the PCA overflow flag CF (in the CCON SFR) to be set when the PCA timer overflows. These functions are shown in Figure 15.

The watchdog timer function is implemented in module 4 (see Figure 24).

The CCON SFR contains the run control bit for the PCA and the flags for the PCA timer (CF) and each module (refer to Figure 18). To run the PCA the CR bit (CCON.6) must be set by software. The PCA is shut off by clearing this bit. The CF bit (CCON.7) is set when the PCA counter overflows and an interrupt will be generated if the

ECF bit in the CMOD register is set, The CF bit can only be cleared by software. Bits 0 through 4 of the CCON register are the flags for the modules (bit 0 for module 0, bit 1 for module 1, etc.) and are set by hardware when either a match or a capture occurs. These flags also can only be cleared by software. The PCA interrupt system shown in Figure 16.

Each module in the PCA has a special function register associated with it. These registers are: CCAPM0 for module 0, CCAPM1 for module 1, etc. (see Figure 19). The registers contain the bits that control the mode that each module will operate in. The ECCF bit (CCAPMn.0 where n=0, 1, 2, 3, or 4 depending on the module) enables the CCF flag in the CCON SFR to generate an interrupt when a match or compare occurs in the associated module. PWM (CCAPMn.1) enables the pulse width modulation mode. The TOG bit (CCAPMn.2) when set causes the CEX output associated with the module to toggle when there is a match between the PCA counter and the module’s capture/compare register. The match bit MAT (CCAPMn.3) when set will cause the CCFn bit in the CCON register to be set when there is a match between the PCA counter and the module’s capture/compare register.

The next two bits CAPN (CCAPMn.4) and CAPP (CCAPMn.5) determine the edge that a capture input will be active on. The CAPN bit enables the negative edge, and the CAPP bit enables the positive edge. If both bits are set both edges will be enabled and a capture will occur for either transition. The last bit in the register ECOM (CCAPMn.6) when set enables the comparator function. Figure 20 shows the CCAPMn settings for the various PCA functions.

There are two additional registers associated with each of the PCA modules. They are CCAPnH and CCAPnL and these are the registers that store the 16-bit count when a capture occurs or a compare should occur. When a module is used in the PWM mode these registers are used to control the duty cycle of the output.

MODULE FUNCTIONS:

16-BIT CAPTURE 16-BIT TIMER 16-BIT HIGH SPEED OUTPUT 8-BIT PWM WATCHDOG TIMER (MODULE 4 ONLY)

MODULE 0

MODULE 1

MODULE 2

MODULE 3

MODULE 4

P1.3/CEX0

P1.4/CEX1

P1.5/CEX2

P1.6/CEX3

P1.7/CEX4

16 BITS

PCA TIMER/COUNTER

TIME BASE FOR PCA MODULES

16 BITS

SU00032

Figure 14. Programmable Counter Array (PCA)

Page 22

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

CF CR CCF4 CCF3 CCF2 CCF1 CCF0––

CCON

(D8H)

CH CL

OVERFLOW

INTERRUPT

16–BIT UP COUNTER

IDLE

TO PCA

MODULES

CMOD

(D9H)

CIDL WDTE –– –– –– CPS1 CPS0 ECF

OSC/12

OSC/4

TIMER 0

OVERFLOW

EXTERNAL INPUT

(P1.2/ECI)

DECODE

00 01 10 11

SU00033

Figure 15. PCA Timer/Counter

MODULE 0

MODULE 1

MODULE 2

MODULE 3

MODULE 4

PCA TIMER/COUNTER

CF CR CCF4 CCF3 CCF2 CCF1 CCF0––

CMOD.0 ECF

CCAPMn.0 ECCFn

TO INTERRUPT PRIORITY DECODER

CCON

(D8H)

IE.6

IE.7

SU00034

Figure 16. PCA Interrupt System

Page 23

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

CMOD Address = OD9H

Reset Value = 00XX X000B

CIDL WDTE – – – CPS1 CPS0 ECF

Bit:

Symbol Function

CIDL Counter Idle control: CIDL = 0 programs the PCA Counter to continue functioning during idle Mode. CIDL = 1 programs

it to be gated off during idle. WDTE Watchdog Timer Enable: WDTE = 0 disables Watchdog T imer function on PCA Module 4. WDTE = 1 enables it. – Not implemented, reserved for future use.*

CPS1 PCA Count Pulse Select bit 1. CPS0 PCA Count Pulse Select bit 0.

CPS1 CPS0 Selected PCA Input**

0 0 0 Internal clock, f

OSC

÷ 12

0 1 1 Internal clock, f

OSC

÷ 4 1 0 2 Timer 0 overflow 1 1 3 External clock at ECI/P1.2 pin (max. rate = f

OSC

÷ 8)

ECF PCA Enable Counter Overflow interrupt: ECF = 1 enables CF bit in CCON to generate an interrupt. ECF = 0 disables

that function of CF.

NOTE:

* 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.

** f

OSC

= oscillator frequency

SU00035

76543210

Figure 17. CMOD: PCA Counter Mode Register

CCON Address = OD8H

Reset Value = 00X0 0000B

CF CR – CCF4 CCF3 CCF2 CCF1 CCF0

Bit Addressable

Bit:

Symbol Function CF PCA Counter Overflow flag. Set by hardware when the counter rolls over. CF flags an interrupt if bit ECF in CMOD is

set. CF may be set by either hardware or software but can only be cleared by software.

CR PCA Counter Run control bit. Set by software to turn the PCA counter on. Must be cleared by software to turn the PCA

counter off.

– Not implemented, reserved for future use*.

CCF4 PCA Module 4 interrupt flag. Set by hardware when a match or capture occurs. Must be cleared by software. CCF3 PCA Module 3 interrupt flag. Set by hardware when a match or capture occurs. Must be cleared by software. CCF2 PCA Module 2 interrupt flag. Set by hardware when a match or capture occurs. Must be cleared by software. CCF1 PCA Module 1 interrupt flag. Set by hardware when a match or capture occurs. Must be cleared by software. CCF0 PCA Module 0 interrupt flag. Set by hardware when a match or capture occurs. Must be cleared by software.

NOTE:

* 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.

SU00036

76543210

Figure 18. CCON: PCA Counter Control Register

Page 24

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

CCAPMn Address CCAPM0 0DAH

CCAPM1 0DBH CCAPM2 0DCH CCAPM3 0DDH CCAPM4 0DEH

Reset Value = X000 0000B

– ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn

Not Bit Addressable

Bit:

Symbol Function – Not implemented, reserved for future use*.

ECOMn Enable Comparator. ECOMn = 1 enables the comparator function. CAPPn Capture Positive, CAPPn = 1 enables positive edge capture. CAPNn Capture Negative, CAPNn = 1 enables negative edge capture. MATn Match. When MATn = 1, a match of the PCA counter with this module’s compare/capture register causes the CCFn bit

in CCON to be set, flagging an interrupt.

TOGn T oggle. When TOGn = 1, a match of the PCA counter with this module’s compare/capture register causes the CEXn

pin to toggle.

PWMn Pulse Width Modulation Mode. PWMn = 1 enables the CEXn pin to be used as a pulse width modulated output. ECCFn Enable CCF interrupt. Enables compare/capture flag CCFn in the CCON register to generate an interrupt.

NOTE:

*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.

SU00037

76543210

Figure 19. CCAPMn: PCA Modules Compare/Capture Registers

–

ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn MODULE FUNCTION

X 0 0 0 0 0 0 0 No operation X X 1 0 0 0 0 X 16-bit capture by a positive-edge trigger on CEXn X X 0 1 0 0 0 X 16-bit capture by a negative trigger on CEXn X X 1 1 0 0 0 X 16-bit capture by a transition on CEXn X 1 0 0 1 0 0 X 16-bit Software Timer X 1 0 0 1 1 0 X 16-bit High Speed Output X 1 0 0 0 0 1 0 8-bit PWM X 1 0 0 1 X 0 X Watchdog Timer

Figure 20. PCA Module Modes (CCAPMn Register)

PCA Capture Mode

To use one of the PCA modules in the capture mode either one or both of the CCAPM bits CAPN and CAPP for that module must be set. The external CEX input for the module (on port 1) is sampled for a transition. When a valid transition occurs the PCA hardware loads the value of the PCA counter registers (CH and CL) into the module’s capture registers (CCAPnL and CCAPnH). If the CCFn bit for the module in the CCON SFR and the ECCFn bit in the CCAPMn SFR are set then an interrupt will be generated. Refer to Figure 21.

16-bit Software Timer Mode

The PCA modules can be used as software timers by setting both the ECOM and MAT bits in the modules CCAPMn register. The PCA timer will be compared to the module’s capture registers and when a match occurs an interrupt will occur if the CCFn (CCON SFR) and the ECCFn (CCAPMn SFR) bits for the module are both set (see Figure 22).

High Speed Output Mode

In this mode the CEX output (on port 1) associated with the PCA module will toggle each time a match occurs between the PCA counter and the module’s capture registers. To activate this mode the TOG, MA T, and ECOM bits in the module’ s CCAPMn SFR must be set (see Figure 23).

Pulse Width Modulator Mode

All of the PCA modules can be used as PWM outputs. Figure 24 shows the PWM function. The frequency of the output depends on the source for the PCA timer. All of the modules will have the same frequency of output because they all share the PCA timer. The duty cycle of each module is independently variable using the module’s capture register CCAPLn. When the value of the PCA CL SFR is less than the value in the module’s CCAPLn SFR the output will be low, when it is equal to or greater than the output will be high. When CL overflows from FF to 00, CCAPLn is reloaded with the value in CCAPHn. the allows updating the PWM without glitches. The PWM and ECOM bits in the module’s CCAPMn register must be set to enable the PWM mode.

Page 25

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

CF CR CCF4 CCF3 CCF2 CCF1 CCF0––

CCON

(D8H)

–– ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn

CCAPMn, n= 0 to 4

(DAH – DEH)

CH CL

CCAPnH CCAPnL

CEXn

CAPTURE

PCA INTERRUPT

PCA TIMER/COUNTER

0 000

(TO CCFn)

SU00749

Figure 21. PCA Capture Mode

MATCH

CF CR CCF4 CCF3 CCF2 CCF1 CCF0––

CCON

(D8H)

–– ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn

CCAPMn, n= 0 to 4

(DAH – DEH)

CH CL

CCAPnH

CCAPnL

PCA INTERRUPT

PCA TIMER/COUNTER

0000

16–BIT COMPARATOR

(TO CCFn)

ENABLE

WRITE TO

CCAPnH

RESET

WRITE TO

CCAPnL

SU00750

Figure 22. PCA Compare Mode

Page 26

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

CF CR CCF4 CCF3 CCF2 CCF1 CCF0––

CCON

(D8H)

–– ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn

CCAPMn, n: 0..4

(DAH – DEH)

CH CL

CCAPnH CCAPnL

PCA INTERRUPT

PCA TIMER/COUNTER

1000

16–BIT COMPARATOR

(TO CCFn)

WRITE TO

CCAPnH

RESET

WRITE TO

CCAPnL

ENABLE

CEXn

TOGGLE

MATCH

SU00751

Figure 23. PCA High Speed Output Mode

CL < CCAPnL

–– ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn

CCAPMn, n: 0..4

(DAH – DEH)

PCA TIMER/COUNTER

0000

CCAPnL

CEXn

8–BIT

COMPARATOR

OVERFLOW

CCAPnH

ENABLE

CL >= CCAPnL

SU00752

Figure 24. PCA PWM Mode

Page 27

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

–– ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn

CCAPM4 (DEH)

CH CL

CCAP4H CCAP4L

RESET

PCA TIMER/COUNTER

X000

16–BIT COMPARATOR

MATCH

ENABLE

WRITE TO CCAP4H

RESET

WRITE TO CCAP4L

CMOD (D9H)

CIDL WDTE –– –– –– CPS1 CPS0 ECF

SU00832

MODULE 4

Figure 25. PCA Watchdog Timer m(Module 4 only)

PCA Watchdog Timer

An on-board watchdog timer is available with the PCA to improve the reliability of the system without increasing chip count. Watchdog timers are useful for systems that are susceptible to noise, power glitches, or electrostatic discharge. Module 4 is the only PCA module that can be programmed as a watchdog. However, this module can still be used for other modes if the watchdog is not needed.

Figure 25 shows a diagram of how the watchdog works. The user pre-loads a 16-bit value in the compare registers. Just like the other compare modes, this 16-bit value is compared to the PCA timer value. If a match is allowed to occur, an internal reset will be generated. This will not cause the RST pin to be driven high.

In order to hold off the reset, the user has three options:

1. periodically change the compare value so it will never match the PCA timer,

2. periodically change the PCA timer value so it will never match the compare values, or

3. disable the watchdog by clearing the WDTE bit before a match occurs and then re-enable it.

The first two options are more reliable because the watchdog timer is never disabled as in option #3. If the program counter ever goes astray, a match will eventually occur and cause an internal reset. The second option is also not recommended if other PCA modules are being used. Remember , the PCA timer is the time base for all modules; changing the time base for other modules would not be a good idea. Thus, in most applications the first solution is the best option.

Figure 26 shows the code for initializing the watchdog timer. Module 4 can be configured in either compare mode, and the WDTE bit in CMOD must also be set. The user’s software then must periodically change (CCAP4H,CCAP4L) to keep a match from occurring with the PCA timer (CH,CL). This code is given in the WATCHDOG routine in Figure 26.

This routine should not be part of an interrupt service routine, because if the program counter goes astray and gets stuck in an infinite loop, interrupts will still be serviced and the watchdog will keep getting reset. Thus, the purpose of the watchdog would be defeated. Instead, call this subroutine from the main program within 2

count of the PCA timer.

Page 28

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

INIT_WATCHDOG: MOV CCAPM4, #4CH ; Module 4 in compare mode MOV CCAP4L, #0FFH ; Write to low byte first MOV CCAP4H, #0FFH ; Before PCA timer counts up to ; FFFF Hex, these compare values ; must be changed ORL CMOD, #40H ; Set the WDTE bit to enable the ; watchdog timer without changing ; the other bits in CMOD ; ;******************************************************************** ; ; Main program goes here, but CALL WATCHDOG periodically. ; ;******************************************************************** ; WATCHDOG: CLR EA ; Hold off interrupts MOV CCAP4L, #00 ; Next compare value is within MOV CCAP4H, CH ; 255 counts of the current PCA SETB EA ; timer value RET

Figure 26. PCA Watchdog Timer Initialization Code

Page 29

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

Expanded Data RAM Addressing

The 89C51RX+ has internal data memory that is mapped into four separate segments: the lower 128 bytes of RAM, upper 128 bytes of RAM, 128 byte s S pecial Function Register (SFR), and 256 bytes (768 for RD+) expanded RAM (ERAM).

The four segments are:

1. The Lower 128 bytes of RAM (addresses 00H to 7FH) are directly and indirectly addressable.

2. The Upper 128 bytes of RAM (addresses 80H to FFH) are indirectly addressable only.

3. The Special Function Registers, SFRs, (addresses 80H to FFH) are directly addressable only.

4. The 256-bytes (768 for RD+) expanded RAM (ERAM, 00H – FFH) are indirectly accessed by move external instruction, MOVX, and with the EXTRAM bit cleared, see Figure 27.

The Lower 128 bytes can be accessed by either direct or indirect addressing. The Upper 128 bytes can be accessed by indirect addressing only . The Upper 128 bytes occupy the same address space as the SFR. That means they have the same address, but are physically separate from SFR space.

When an instruction accesses an internal location above address 7FH, the CPU knows whether the access is to the upper 128 bytes of data RAM or to SFR space by the addressing mode used in the instruction. Instructions that use direct addressing access SFR space. For example:

MOV 0A0H,#data

accesses the SFR at location 0A0H (which is P2). Instructions that use indirect addressing access the Upper 128 bytes of data RAM.

For example:

MOV @R0,#data

where R0 contains 0A0H, accesses the data byte at address 0A0H, rather than P2 (whose address is 0A0H).

The ERAM can be accessed by indirect addressing, with EXTRAM bit cleared and MOVX instructions. This part of memory is physically located on-chip, logically occupies the first 256-bytes (768 for RD+) of external data memory.

With EXTRAM = 0, the ERAM is indirectly addressed, using the MOVX instruction in combination with any of the registers R0, R1 of the selected bank or DPTR. An access to ERAM will not affect ports P0, P3.6 (WR#) and P3.7 (RD#). P2 SFR is output during external addressing. For example, with EXTRAM = 0,

MOVX @R0,#data

where R0 contains 0A0H, access the ERAM at address 0A0H rather than external memory . An access to external data memory locations higher than FFH (2FF for RD+) (i.e., 0100H to FFFFH) will be performed with the MOVX DPTR instructions in the same way as in the standard 80C51, so with P0 and P2 as data/address bus, and P3.6 and P3.7 as write and read timing signals. Refer to Figure 28.

With EXTRAM = 1, MOVX @Ri and MOVX @DPTR will be similar to the standard 80C51. MOVX @ Ri will provide an 8-bit address multiplexed with data on Port 0 and any output port pins can be used to output higher order address bits. This is to provide the external paging capability. MOVX @DPTR will generate a 16-bit address. Port 2 outputs the high-order eight address bits (the contents of DPH) while Port 0 multiplexes the low-order eight address bits (DPL) with data. MOVX @Ri and MOVX @DPTR will generate either read or write signals on P3.6 (WR

) and P3.7 (RD).

The stack pointer (SP) may be located anywhere in the 256 bytes RAM (lower and upper RAM) internal data memory. The stack may not be located in the ERAM.

AUXR

Reset Value = xxxx xx00B

— —————EXTRAM AO

Not Bit Addressable

Bit:

Symbol Function AO Disable/Enable ALE

AO Operating Mode

0 ALE is emitted at a constant rate of 1/6 the oscillator frequency. 1 ALE is active only during a MOVX or MOVC instruction.

EXTRAM Internal/External RAM (00H – FFH) access using MOVX @Ri/@DPTR

EXTRAM Operating Mode

0 Internal ERAM (00H–FFH) (00H–2FFH for RD+) access using MOVX @Ri/@DPTR 1 External data memory access.

— Not implemented, reserved for future use*.

NOTE:

SU00833A

76543210

Address = 8EH

Figure 27. AUXR: Auxiliary Register (RX+ only)

Page 30

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

ERAM

256 BYTES

UPPER

128 BYTES

INTERNAL RAM

LOWER

128 BYTES

INTERNAL RAM

SPECIAL FUNCTION REGISTER

2FF

(89C51RD+)

80 80

EXTERNAL

DATA

MEMORY

FFFF

0000

0100

300 (89C51RD+)

SU00885

Figure 28. Internal and External Data Memory Address Space with EXTRAM = 0

HARDWARE WATCHDOG TIMER (ONE-TIME ENABLED WITH RESET-OUT FOR 89C51RX+)

The WDT is intended as a recovery method in situations where the CPU may be subjected to software upset. The WDT consists of a 14-bit counter and the WatchDog Timer reset (WDTRST) SFR. The WDT is disabled at reset. To enable the WDT , user must write 01EH and 0E1H in sequence to the WDTRST, SFR location 0A6H. When WDT is enabled, it will increment every machine cycle while the oscillator is running and there is no way to disable the WDT except through reset (either hardware reset or WDT overflow reset). When WDT overflows, it will drive an output reset HIGH pulse at the RST-pin (see the note below).

Using the WDT

To enable the WDT, user must write 01EH and 0E1H in sequence to the WDTRST, SFR location 0A6H. When WDT is enabled, the user needs to service it by writing to 01EH and 0E1H to WDTRST to avoid WDT overflow. The 14-bit counter overflows when it reaches 16383 (3FFFH) and this will reset the device. When WDT is enabled, it will increment every machine cycle while the oscillator is running. This means the user must reset the WDT at least every 16383 machine cycles. To reset the WDT , the user must write 01EH and 0E1H to WDTRST. WDTRST is a write only register. The WDT counter cannot be read or written. When WDT overflows, it will generate an output RESET pulse at the reset pin (see note below). The RESET pulse duration is 98 × T

OSC

, where T

OSC

= 1/f

OSC

. To make the best use of the WDT, it should be serviced in those sections of code that will periodically be executed within the time required to prevent a WDT reset.

NOTE: Applications which use the Watchdog Timer will need to include a series resistor (1 k, ±20%) between the reset pin and ANY external components. Without this series resistor the Watchdog Timer will not function.

Page 31

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

ABSOLUTE MAXIMUM RATINGS

1, 2, 3

PARAMETER

RATING UNIT

Operating temperature under bias 0 to +70 or –40 to +85 °C Storage temperature range –65 to +150 °C Voltage on EA/VPP pin to V

0 to +13.0 V

Voltage on any other pin to V

–0.5 to +6.5 V Maximum IOL per I/O pin 15 mA 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 V

unless otherwise

noted.

Page 32

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

DC ELECTRICAL CHARACTERISTICS

amb

= 0°C to +70°C or –40°C to +85°C; 5 V ±10%; VSS = 0 V

TEST

LIMITS

SYMBOL

PARAMETER

CONDITIONS

MIN TYP

MAX

UNIT

Input low voltage 4.5 V < VCC < 5.5 V –0.5 0.2VCC–0.1 V

Input high voltage (ports 0, 1, 2, 3, EA) 0.2VCC+0.9 VCC+0.5 V

IH1

Input high voltage, XTAL1, RST 0.7V

VCC+0.5 V

Output low voltage, ports 1, 2, 3

VCC = 4.5 V

IOL = 1.6 mA

0.4 V

OL1

Output low voltage, port 0, ALE, PSEN

8, 7

VCC = 4.5 V

IOL = 3.2 mA

0.4 V

Output high voltage, ports 1, 2, 3

VCC = 4.5 V

IOH = –30 µA

VCC – 0.7 V

OH1

Output high voltage (port 0 in external bus mode), ALE9, PSEN

VCC = 4.5 V

IOH = –3.2 mA

VCC – 0.7 V

Logical 0 input current, ports 1, 2, 3 VIN = 0.4 V –1 –75 µA

Logical 1-to-0 transition current, ports 1, 2, 3

VIN = 2.0 V See Note 4

–650 µA

Input leakage current, port 0 0.45 < VIN < VCC – 0.3 ±10 µA

Power supply current (see Figure 36): See Note 5

Active mode (see Note 5) Idle mode (see Note 5) Power-down mode or clock stopped (see

amb

= 0°C to 70°C 20 100 µA

Figure 40 for conditions)

amb

= –40°C to +85°C 125 µA

Programming current 11.5 V  VPP  12.5 V 50 mA

RST

Internal reset pull-down resistor 40 225 kΩ

Pin capacitance10 (except EA) 15 pF

NOTES:

1. Typical ratings are not guaranteed. The values listed are at room temperature, 5 V.

2. Capacitive loading on ports 0 and 2 may cause spurious noise to be superimposed on the V

s 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 the worst cases (capacitive loading > 100 pF), the noise pulse on the ALE pin may exceed 0.8 V . 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. I

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 V

on ALE and PSEN to momentarily fall below the VCC–0.7 specification when the

address bits are stabilizing.

4. Pins of ports 1, 2 and 3 source a transition current when they are being externally driven from 1 to 0. The transition current reaches its maximum value when V

is approximately 2 V .

5. See Figures 37 through 40 for I

test conditions and Figure 36 for I

vs Freq.

Active mode: I

CC(MAX)

= (0.9 × FREQ. + 20)mA for all devices.

Idle mode: I

CC(MAX)

= (0.37 × FREQ. +1.0)mA

6. This value applies to T

amb

= 0°C to +70°C.

7. Load capacitance for port 0, ALE, and PSEN

= 100 pF, load capacitance for all other outputs = 80 pF .

8. Under steady state (non-transient) conditions, I

must be externally limited as follows:

Maximum I

per port pin: 15 mA (*NOTE: This is 85°C specification.)

Maximum I

per 8-bit port: 26 mA

Maximum total I

for all outputs: 71 mA

If I

exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater than the listed

test conditions.

9. ALE is tested to V

OH1

, except when ALE is off then VOH is the voltage specification.

10.Pin capacitance is characterized but not tested. Pin capacitance is less than 25 pF. Pin capacitance of ceramic package is l ess than 15 pF (except EA

is 25 pF).

Page 33

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

AC ELECTRICAL CHARACTERISTICS

amb

= 0°C to +70°C or –40°C to +85°C, VCC = 5 V ±10%, VSS = 0 V

1, 2, 3

VARIABLE CLOCK

33MHz CLOCK

SYMBOL FIGURE PARAMETER MIN MAX MIN MAX UNIT

1/t

CLCL

29 Oscillator frequency

Speed versions: I;J;U (33 MHz)

3.5 33

MHz

LHLL

29 ALE pulse width 2t

CLCL

–40 21 ns

AVLL

29 Address valid to ALE low t

CLCL

–25 5 ns

LLAX

29 Address hold after ALE low t

CLCL

–25 5 ns

LLIV

29 ALE low to valid instruction in 4t

CLCL

–65 55 ns

LLPL

29 ALE low to PSEN low t

CLCL

–25 5 ns

PLPH

29 PSEN pulse width 3t

CLCL

–45 45 ns

PLIV

29 PSEN low to valid instruction in 3t

CLCL

–60 30 ns

PXIX

29 Input instruction hold after PSEN 0 0 ns

PXIZ

29 Input instruction float after PSEN t

CLCL

–25 5 ns

AVIV

29 Address to valid instruction in 5t

CLCL

–80 70 ns

PLAZ

29 PSEN low to address float 10 10 ns

Data Memory

RLRH

30, 31 RD pulse width 6t

CLCL

–100 82 ns

WLWH

30, 31 WR pulse width 6t

CLCL

–100 82 ns

RLDV

30, 31 RD low to valid data in 5t

CLCL

–90 60 ns

RHDX

30, 31 Data hold after RD 0 0 ns

RHDZ

30, 31 Data float after RD 2t

CLCL

–28 32 ns

LLDV

30, 31 ALE low to valid data in 8t

CLCL

–150 90 ns

AVDV

30, 31 Address to valid data in 9t

CLCL

–165 105 ns

LLWL

30, 31 ALE low to RD or WR low 3t

CLCL

–50 3t

CLCL

+50 40 140 ns

AVWL

30, 31 Address valid to WR low or RD low 4t

CLCL

–75 45 ns

QVWX

30, 31 Data valid to WR transition t

CLCL

–30 0 ns

WHQX

30, 31 Data hold after WR t

CLCL

–25 5 ns

QVWH

31 Data valid to WR high 7t

CLCL

–130 80 ns

RLAZ

30, 31 RD low to address float 0 0 ns

WHLH

30, 31 RD or WR high to ALE high t

CLCL

–25 t

CLCL

+25 5 55 ns

External Clock

CHCX

33 High time 17 t

CLCL–tCLCX

CLCX

33 Low time 17 t

CLCL–tCHCX

CLCH

33 Rise time 5 ns

CHCL

33 Fall time 5 ns

Shift Register

XLXL

32 Serial port clock cycle time 12t

CLCL

360 ns

QVXH

32 Output data setup to clock rising edge 10t

CLCL

–133 167 ns

XHQX

32 Output data hold after clock rising edge 2t

CLCL

–80 50 ns

XHDX

32 Input data hold after clock rising edge 0 0 ns

XHDV

32 Clock rising edge to input data valid 10t

CLCL

–133 167 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 microcontroller 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.

Page 34

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

EXPLANATION OF THE AC SYMBOLS

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

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: t

AVLL

= Time for address valid to ALE low .

LLPL

=Time for ALE low to PSEN low.

PXIZ

ALE

PSEN

PORT 0

PORT 2

A0–A15 A8–A15

A0–A7 A0–A7

AVLL

PXIX

LLAX

INSTR IN

LHLL

PLPH

LLIV

PLAZ

LLPL

AVIV

SU00006

PLIV

Figure 29. External Program Memory Read Cycle

ALE

PSEN

PORT 0

PORT 2

A0–A7

FROM RI OR DPL

DATA IN A0–A7 FROM PCL INSTR IN

P2.0–P2.7 OR A8–A15 FROM DPF A0–A15 FROM PCH

WHLH

LLDV

LLWL

RLRH

LLAX

RLAZ

AVLL

RHDX

RHDZ

AVWL

AVDV

RLDV

SU00025

Figure 30. External Data Memory Read Cycle

Page 35

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

LLAX

ALE

PSEN

PORT 0

PORT 2

A0–A7

FROM RI OR DPL

DATA OUT A0–A7 FROM PCL INSTR IN

P2.0–P2.7 OR A8–A15 FROM DPF A0–A15 FROM PCH

WHLH

LLWL

WLWH

AVLL

AVWL

QVWX

WHQX

QVWH

SU00026

Figure 31. External Data Memory Write Cycle

012345678

INSTRUCTION

ALE

CLOCK

OUTPUT DATA

WRITE TO SBUF

INPUT DATA

CLEAR RI

VALID VALID VALID VALID VALID VALID VALID VALID

SET TI

SET RI

XLXL

QVXH

XHQX

XHDX

XHDV

SU00027

1230 4567

Figure 32. Shift Register Mode Timing

VCC–0.5

0.45V

0.7V

0.2VCC–0.1

CHCL

CLCL

CLCH

CLCX

CHCX

SU00009

Figure 33. External Clock Drive

Page 36

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

VCC–0.5

0.45V

0.2V

+0.9

0.2V

–0.1

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’.

SU00717

Figure 34. AC Testing Input/Output

LOAD

+0.1V

LOAD

–0.1V

+0.1V

NOTE:

TIMING

REFERENCE

POINTS

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 V

OH/VOL

level occurs. IOH/IOL ≥ ±20mA.

SU00718

Figure 35. Float Waveform

4 8 12 16 20 24 28 32 36

Frequency at XTAL1 (MHz)

(mA)

SU01314

Icc IDLE MODE (TYP.)

Icc ACTIVE MODE (TYP.)

Figure 36. ICC vs. FREQ

Valid only within frequency specifications of the device under test

Page 37

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

RST

XTAL1

XTAL2

(NC)

CLOCK SIGNAL

SU00719

Figure 37. ICC Test Condition, Active Mode

All other pins are disconnected

P0 EA

RST

XTAL1

XTAL2

(NC)

CLOCK SIGNAL

SU00720

Figure 38. ICC Test Condition, Idle Mode

All other pins are disconnected

VCC–0.5

0.45V

0.7V

0.2VCC–0.1

CHCL

CLCL

CLCH

CLCX

CHCX

SU00009

Figure 39. Clock Signal Waveform for ICC Tests in Active and Idle Modes

CLCH

= t

CHCL

= 5 ns

RST

XTAL1

XTAL2

(NC)

SU00016

Figure 40. ICC Test Condition, Power Down Mode

All other pins are disconnected. V

= 2 V to 5.5 V

Page 38

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

FLASH EPROM MEMORY

GENERAL DESCRIPTION

The 89C51RX+ FLASH memory augments EPROM functionality with in-circuit electrical erasure and programming. The FLASH can be read and written as bytes. The Chip Erase operation will erase the entire program memory. The Block Erase function can erase any FLASH byte block. In-system programming and standard parallel programming are both available. On-chip erase and write timing generation contribute to a user friendly programming interface.

The 89C51RX+ FLASH reliably stores memory contents even after 1000 erase and program cycles. The cell is designed to optimize the erase and programming mechanisms. In addition, the combination of advanced tunnel oxide processing and low internal electric fields for erase and programming operations produces reliable cycling. The 89C51RX+ uses a 12.0 V ±0.5 V V

supply to perform the

Program/Erase algorithms.

FEA TURES

•FLASH EPROM internal program memory with Block Erase.

•Internal 1 k byte fixed boot ROM, containing low-level in-system

programming routines and a default serial loader. The Boot ROM can be turned off to provide access to the full 64 k byte FLASH memory.

•Boot vector allows user provided FLASH loader code to reside

anywhere in the FLASH memory space. This configuration provides flexibility to the user.

•Default loader in Boot ROM allows programming via the serial port

without the need for a user provided loader.

•Up to 64 k byte external program memory if the internal program

memory is disabled (EA

= 0).

•Programming and erase voltage 12 V ±0.5 V.

•Read/Programming/Erase:

– Byte-wise read (100 ns access time). – Byte Programming (20 µs). – Typical erase times:

Block Erase (8 k bytes or 16 k bytes) in 3 seconds. Full Erase (64 k bytes) in 3 seconds.

•Parallel programming with 87C51 compatible hardware interface

to programmer.

•In-circuit programming.

•Programmable security for the code in the FLASH.

•1000 minimum erase/program cycles for each byte.

•10 year minimum data retention.

CAPABILITIES OF THE PHILIPS 89C51 FLASH-BASED MICROCONTROLLERS

FLASH organization (89C51RC+ and 89C51RD+)

The 89C51RD+ contains 64 k bytes of FLASH program memory. This memory is organized as 5 separate blocks. The first two blocks are 8 k bytes in size, filling the program memory space from address 0 through 3FFF hex. The final three blocks are 16 k bytes in size and occupy addresses from 4000 through FFFF hex.

The 89C51RC+ contains 32 k bytes of FLASH program memory, which is organized as two blocks of 8k bytes, followed by one block of 16 k bytes.

Figure 41 depicts the FLASH memory configurations.

FLASH Programming and Erasure

There are three methods of erasing or programming of the FLASH memory that may be used. First, the FLASH may be programmed or erased in the end-user application by calling low-level routines through a common entry point in the Boot ROM. The end-user application, though, must be executing code from a different block than the block that is being erased or programmed. Second, the on-chip ISP boot loader may be invoked. This ISP boot loader will, in turn, call low-level routines through the same common entry point in the Boot ROM that can be used by the end-user application. Third, the FLASH may be programmed or erased using the parallel method by using a commercially available EPROM programmer. The parallel programming method used by these devices is similar to that used by EPROM 87C51, but it is not identical, and the commercially available programmer will need to have support for these devices.

Boot ROM

When the microcontroller programs its own FLASH memory, all of the low level details are handled by code that is permanently contained in a 1 k byte “Boot ROM” that is separate from the FLASH memory. A user program simply calls the common entry point with appropriate parameters in the Boot ROM to accomplish the desired operation. Boot ROM operations include things like: erase block, program byte, verify byte, program security lock bit, etc. The Boot ROM overlays the program memory space at the top of the address space from FC00 to FFFF hex, when it is enabled. The Boot ROM may be turned off so that the upper 1k bytes of FLASH program memory are accessible for execution.

Page 39

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

FFFF

C000

8000

4000

2000

0000

BLOCK 4

16k BYTES

BLOCK 3

16k BYTES

BLOCK 2

16k BYTES

BLOCK 1

8k BYTES

BLOCK 0

8k BYTES

PROGRAM

ADDRESS

89C51RC+

89C51RD+

BOOT ROM

(1k BYTES ON

ALL PARTS)

FFFF FC00

SU01041

Figure 41. FLASH Memory Configurations

Power-On Reset Code Execution

The 89C51RX+ contains two special FLASH registers: the BOOT VECTOR and the STATUS BYTE. At the falling edge of reset, the 89C51RX+ examines the contents of the Status Byte. If the Status Byte is set to zero, power-up execution starts at location 0000H, which is the normal start address of the user’s application code. When the Status Byte is set to a value other than zero, the contents of the Boot Vector is used as the high byte of the execution address and the low byte is set to 00H. The factory default setting is 0FCH, corresponds to the address 0FC00H for the factory masked-ROM ISP boot loader. A custom boot loader can be written with the Boot Vector set to the custom boot loader.

NOTE: When erasing the Status Byte or Boot Vector, both bytes are erased at the same time. It is necessary to reprogram the Boot Vector after erasing and updating the Status Byte.

Hardware Activation of the Boot Loader

The boot loader can also be executed by holding PSEN LOW, EA

greater than VIH (such as +12 V), and ALE HIGH (or not connected) at the falling edge of RESET. This is the same effect as having a non-zero status byte. This allows an application to be built that will normally execute the end user’s code but can be manually forced into ISP operation.

If the factory default setting for the Boot Vector (0FCH) is changed, it will no longer point to the ISP masked-ROM boot loader code. If this happens, the only way it is possible to change the contents of the Boot Vector is through the parallel programming method, provided that the end user application does not contain a customized loader that provides for erasing and reprogramming of the Boot Vector and Status Byte.

After programming the FLASH, the status byte should be programmed to zero in order to allow execution of the user’s application code beginning at address 0000H.

Page 40

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

+12V

+5V TxD RxD V

TxD RxD

RST

XTAL2

XTAL1

SU01042

Figure 42. In-System Programming with a Minimum of Pins

In-System Programming (ISP)

The In-System Programming (ISP) is performed without removing the microcontroller from the system. The In-System Programming (ISP) facility consists of a series of internal hardware resources coupled with internal firmware to facilitate remote programming of the 89C51RX+ through the serial port. This firmware is provided by Philips and embedded within each 89C51RX+ device.

The Philips In-System Programming (ISP) facility has made in-circuit programming in an embedded application possible with a minimum of additional expense in components and circuit board area.

The ISP function uses five pins: TxD, RxD, V

, VCC, and VPP (see Figure 42). Only a small connector needs to be available to interface your application to an external circuit in order to use this feature. The V

supply should be adequately decoupled and provide a

minimum 50mA. V

is not allowed to exceed datasheet limits.

Using the In-System Programming (ISP)

The ISP feature allows for a wide range of baud rates to be used in your application, independent of the oscillator frequency. It is also adaptable to a wide range of oscillator frequencies. This is accomplished by measuring the bit-time of a single bit in a received character. This information is then used to program the baud rate in terms of timer counts based on the oscillator frequency. The ISP feature requires that an initial character (an uppercase U) be sent to the 89C51RX+ to establish the baud rate. The ISP firmware provides auto-echo of received characters.

Once baud rate initialization has been performed, the ISP firmware will only accept Intel Hex-type records. Intel Hex records consist of ASCII characters used to represent hexadecimal values and are summarized below:

:NNAAAARRDD..DDCC<crlf>

In the Intel Hex record, the “NN” represents the number of data bytes in the record. The 89C51RX+ will accept up to 16 (10H) data

bytes. The “AAAA” string represents the address of the first byte in the record. If there are zero bytes in the record, this field is often set to 0000. The “RR” string indicates the record type. A record type of “00” is a data record. A record type of “01” indicates the end-of-file mark. In this application, additional record types will be added to indicate either commands or data for the ISP facility. The maximum number of data bytes in a record is limited to 16 (decimal). ISP commands are summarized in Table 8.

As a record is received by the 89C51RX+, the information in the record is stored internally and a checksum calculation is performed. The operation indicated by the record type is not performed until the entire record has been received. Should an error occur in the checksum, the 89C51RX+ will send an “X” out the serial port indicating a checksum error. If the checksum calculation is found to match the checksum in the record, then the command will be executed. In most cases, successful reception of the record will be indicated by transmitting a “.” character out the serial port (displaying the contents of the internal program memory is an exception).

In the case of a Data Record (record type 00), an additional check is made. A “.” character will NOT be sent unless the record checksum matched the calculated checksum and all of the bytes in the record were successfully programmed. For a data record, an “X” indicates that the checksum failed to match, and an “R” character indicates that one of the bytes did not properly program. It is necessary to send a type 02 record (specify oscillator frequency) to the 89C51RX+ before programming data.

The ISP facility was designed to that specific crystal frequencies were not required in order to generate baud rates or time the programming pulses. The user thus needs to provide the 89C51RX+ with information required to generate the proper timing. Record type 02 is provided for this purpose.

WinISP, a software utility to implement ISP programming with a PC, is available from Philips.

Page 41

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

T able 8. Intel-Hex Records Used by In-System Programming

RECORD TYPE COMMAND/DATA FUNCTION

00 Program Data

:nnaaaa00dd....ddcc

Where:

Nn = number of bytes (hex) in record Aaaa = memory address of first byte in record

dd....dd = data bytes

cc = checksum

Example:

:10008000AF5F67F0602703E0322CFA92007780C3FD

01 End of File (EOF), no operation

:xxxxxx01cc

Where:

xxxxxx = required field, but value is a “don’t care” cc = checksum

Example:

:00000001FF

02 Specify Oscillator Frequency

:01xxxx02ddcc

Where:

xxxx = required field, but value is a “don’t care” dd = integer oscillator frequency rounded down to nearest MHz cc = checksum

Example:

:0100000210ED (dd = 10h = 16, used for 16.0–16.9 MHz)

03 Miscellaneous Write Functions

:nnxxxx03ffssddcc

Where:

nn = number of bytes (hex) in record xxxx = required field, but value is a “don’t care” 03 = Write Function ff = subfunction code ss = selection code dd = data input (as needed) cc = checksum

Subfunction Code = 01 (Erase Blocks)

ff = 01 ss = block code as shown below: block 0, 0k to 8k, 00H block 1, 8k to 16k, 20H block 2, 16k to 32k, 40H block 3, 32k to 48k, 80H block 4, 48k to 64k, C0H

Example:

:0200000301C03A erase block 4

Subfunction Code = 04 (Erase Boot Vector and Status Byte)

ff = 04 ss = don’t care

Example:

:020000030400F7 erase boot vector and status byte

Subfunction Code = 05 (Program Security Bits)

ff = 05 ss = 00 program security bit 1 (inhibit writing to Flash) 01 program security bit 2 (inhibit Flash verify) 02 program security bit 3 (disable external memory)

Example:

:020000030501F5 program security bit 2

Subfunction Code = 06 (Program Status Byte or Boot Vector)

ff = 06 ss = 00 program status byte 01 program boot vector

Example:

:030000030601FCF7 program boot vector with 0FCH

Page 42

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

RECORD TYPE COMMAND/DATA FUNCTION

04 Display Device Data or Blank Check – Record type 04 causes the contents of the entire Flash array to be sent out

the serial port in a formatted display. This display consists of an address and the contents of 16 bytes starting with that address. No display of the device contents will occur if security bit 2 has been programmed. Data to the serial port is initiated by the reception of any character and terminated by the reception of any character.

General Format of Function 04

:05xxxx04sssseeeeffcc

Where:

05 = number of bytes (hex) in record xxxx = required field, but value is a “don’t care” 04 = “Display Device Data or Blank Check” function code ssss = starting address eeee = ending address ff = subfunction

00 = display data 01 = blank check

cc = checksum

Example:

:0500000440004FFF0069 display 4000–4FFF

05 Miscellaneous Read Functions

General Format of Function 05

:02xxxx05ffsscc

Where:

02 = number of bytes (hex) in record xxxx = required field, but value is a “don’t care” 05 = “Miscellaneous Read” function code ffss = subfunction and selection code

0000 = read signature byte – manufacturer id (15H) 0001 = read signature byte – device id # 1 (C2H) 0002 = read signature byte – device id # 2

0700 = read security bits 0701 = read status byte 0702 = read boot vector

cc = checksum

Example:

:020000050001F8 read signature byte – device id # 1

Page 43

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

In Application Programming Method

Several In Application Programming (IAP) calls are available for use by an application program to permit selective erasing and programming of Flash sectors. All calls are made through a common interface, PGM_MTP. The programming functions are selected by setting up

the microcontroller’s registers before making a call to PGM_MTP at FFF0H. The oscillator frequency is an integer number rounded down to the nearest megahertz. For example, set R0 to 11 for 11.0592 MHz. Results are returned in the registers. The IAP calls are shown in Table 9.

Table 9. IAP calls

IAP CALL PARAMETER

PROGRAM DATA BYTE Input Parameters:

R0 = osc freq (integer) R1 = 02h DPTR = address of byte to program ACC = byte to program

Return Parameter

ACC = 00 if pass, !00 if fail

ERASE BLOCK Input Parameters:

R0 = osc freq (integer) R1 = 01h DPH = block code as shown below: block 0, 0k to 8k, 00H block 1, 8k to 16k, 20H block 2, 16k to 32k, 40H block 3, 32k to 48k, 80H block 4, 48k to 64k, C0H

DPL = 00h

Return Parameter

none

ERASE BOOT VECTOR Input Parameters:

R0 = osc freq (integer) R1 = 04h DPH = 00h DPL = don’t care

Return Parameter

none

PROGRAM SECURITY BIT Input Parameters:

R0 = osc freq (integer) R1 = 05h DPH = 00h DPL = 00h – security bit # 1 (inhibit writing to Flash) 01h – security bit # 2 (inhibit Flash verify) 02h – security bit # 3 (disable external memory)

Return Parameter

none

PROGRAM STATUS BYTE Input Parameters:

R0 = osc freq (integer) R1 = 06h DPH = 00h DPL = 00h – program status byte ACC = status byte

Return Parameter

ACC = status byte

PROGRAM BOOT VECTOR Input Parameters:

R0 = osc freq (integer) R1 = 06h DPH = 00h DPL = 01h – program boot vector ACC = boot vector

Return Parameter

ACC = boot vector

READ DEVICE DATA Input Parameters:

R1 = 03h DPTR = address of byte to read

Return Parameter

ACC = value of byte read

Page 44

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

IAP CALL PARAMETER

READ MANUFACTURER ID Input Parameters:

R0 = osc freq (integer) R1 = 00h DPH = 00h DPL = 00h (manufacturer ID)

Return Parameter

ACC = value of byte read

READ DEVICE ID # 1 Input Parameters:

R0 = osc freq (integer) R1 = 00h DPH = 00h DPL = 01h (device ID # 1)

Return Parameter

ACC = value of byte read

READ DEVICE ID # 2 Input Parameters:

R0 = osc freq (integer) R1 = 00h DPH = 00h DPL = 02h (device ID # 2)

Return Parameter

ACC = value of byte read

READ SECURITY BITS Input Parameters:

R0 = osc freq (integer) R1 = 07h DPH = 00h DPL = 00h (security bits)

Return Parameter

ACC = value of byte read

READ STATUS BYTE Input Parameters:

R0 = osc freq (integer) R1 = 07h DPH = 00h DPL = 01h (status byte)

Return Parameter

ACC = value of byte read

READ BOOT VECTOR Input Parameters:

R0 = osc freq (integer) R1 = 07h DPH = 00h DPL = 02h (boot vector)

Return Parameter

ACC = value of byte read

Page 45

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

Security

The security feature protects against software piracy and prevents the contents of the Flash from being read. The Security Lock bits are located in Flash. The P89C51RC+/P89C51RD+ has three programmable security lock bits that will provide different levels of protection for the on-chip code and data (see Table 10).

Table 10.

SECURITY LOCK BITS

LB1 LB2 LB3

PROTECTION DESCRIPTION

X X X MOVC instructions executed from external program memory are disabled from fetching code bytes

from internal memory.

1 X X Block erase is disabled. Erase or programming of the status byte or boot vector is disabled. X 1 X Verify of code memory is disabled. X X 1 External execution is disabled.

NOTE:

1. Security bits are independent of each other. Full-chip erase may be performed regardless of the state of the security bits.

Page 46

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

DIP40: plastic dual in-line package; 40 leads (600 mil) SOT129-1

Page 47

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

PLCC44: plastic leaded chip carrier; 44 leads SOT187-2

Page 48

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

QFP44: plastic quad flat package; 44 leads

Page 49

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

NOTES

Page 50

Philips Semiconductors Product specification

P89C51RC+/P89C51RD+

80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM

1999 Oct 27

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 134). 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, without notice, in the products, including circuits, standard cells, and/or software, described or contained herein in order to improve design and/or performance. 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.

Philips Semiconductors 811 East Arques Avenue P.O. Box 3409 Sunnyvale, California 94088–3409 Telephone 800-234-7381

 Copyright Philips Electronics North America Corporation 1999

Date of release: 10-99

Document order number: 9397-750-06605

 

Data sheet status

Objective specification

Preliminary specification

Product specification

Product status

Development

Qualification

Production

Definition

[1]

This data sheet contains the design target or goal specifications for product development. Specification may change in any manner without notice.

This data sheet contains preliminary data, and supplementary data will be published at a later date. Philips Semiconductors reserves the right to make changes at any time without notice in order to improve design and supply the best possible product.

This data sheet contains final specifications. Philips Semiconductors reserves the right to make changes at any time without notice in order to improve design and supply the best possible product.

Data sheet status

[1] Please consult the most recently issued datasheet before initiating or completing a design.