Datasheet P89C51RD+, P89C51RC+ Datasheet (Philips)

Page 1
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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)
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
2
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 detectionAutomatic address recognition
Power control modes
Clock can be stopped and resumedIdle modePower 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
1
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
1
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
3
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
PP
ALE
RST
XTAL1 XTAL2
V
CC
V
SS
PORT 0
DRIVERS
PORT 2
DRIVERS
RAM ADDR REGISTER
RAM
PORT 0
LATCH
PORT 2
LATCH
FLASH
REGISTER
B
ACC
STACK
POINTER
TMP2
TMP1
ALU
TIMING
AND
CONTROL
INSTRUCTION
REGISTER
PD
OSCILLATOR
PSW
PORT 1
LATCH
PORT 3
LATCH
PORT 1
DRIVERS
PORT 3
DRIVERS
PROGRAM ADDRESS REGISTER
BUFFER
PC
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
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
4
LOGIC SYMBOL
PORT 0
PORT 1PORT 2
PORT 3
ADDRESS AND
DATA BUS
ADDRESS BUS
T2 T2EX
RxD
TxD INT0 INT1
T0 T1
WR
RD
SECONDARY FUNCTIONS
RST
EA/V
PP
PSEN
ALE/PROG
V
SS
V
CC
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
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
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
WR
/P3.6 RD
/P3.7
XTAL2 XTAL1
V
SS
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
EA
/V
PP
P0.7/AD7
P0.6/AD6
P0.5/AD5
P0.4/AD4
P0.3/AD3
P0.2/AD2
P0.1/AD1
P0.0/AD0
V
CC
DUAL
IN-LINE
PACKAGE
PLASTIC LEADED CHIP CARRIER PIN FUNCTIONS
SU00890
LCC
6140
7
17
39
29
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
SS
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
PP
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
CC
* NO INTERNAL CONNECTION
PLASTIC QUAD FLAT PACK PIN FUNCTIONS
SU00891
PQFP
44 34
1
11
33
23
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
SS
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
/V
PP
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
CC
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
5
PIN DESCRIPTIONS
PIN NUMBER
MNEMONIC DIP LCC QFP TYPE NAME AND FUNCTION
V
SS
20 22 16 I Ground: 0 V reference.
V
CC
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
IL
).
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
IL
). 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
IL
). 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
SS
permits a power-on reset using only an external capacitor
to V
CC
.
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
6
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
PP
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
PP
) 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
7
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
8
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
CC
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
9
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
CC
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
CC
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
CC
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
CC
level must remain above 3V for the POF to remain unaffected by the V
CC
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
10
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
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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
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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)
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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”
“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
16
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.
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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
16
If Timer 2 is being clocked internally , the baud rate is:
Baud Rate +
f
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 *
ǒ
f
OSC
32 Baud Rate
Ǔ
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.
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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.
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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
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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
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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)
2
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
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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
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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
IH
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.
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Philips Semiconductors Product specification
P89C51RC+/P89C51RD+
80C51 8-bit Flash microcontroller family 32K/64K ISP FLASH with 512–1K RAM
1999 Oct 27
21
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
22
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
EC
IE.7
EA
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
23
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
24
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
25
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
01
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
26
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
01
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
CL
CCAPnL
CEXn
8–BIT
COMPARATOR
OVERFLOW
CCAPnH
ENABLE
0
1
CL >= CCAPnL
0
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
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
01
1
CMOD (D9H)
CIDL WDTE –– –– –– CPS1 CPS0 ECF
X
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
16
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
28
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
29
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:
*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.
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
30
ERAM
256 BYTES
UPPER
128 BYTES
INTERNAL RAM
LOWER
128 BYTES
INTERNAL RAM
SPECIAL FUNCTION REGISTER
2FF
(89C51RD+)
FF
00
FF
00
FF
00
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
31
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
SS
0 to +13.0 V
Voltage on any other pin to V
SS
–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
SS
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
32
DC ELECTRICAL CHARACTERISTICS
T
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
1
MAX
UNIT
V
IL
Input low voltage 4.5 V < VCC < 5.5 V –0.5 0.2VCC–0.1 V
V
IH
Input high voltage (ports 0, 1, 2, 3, EA) 0.2VCC+0.9 VCC+0.5 V
V
IH1
Input high voltage, XTAL1, RST 0.7V
CC
VCC+0.5 V
V
OL
Output low voltage, ports 1, 2, 3
8
VCC = 4.5 V
IOL = 1.6 mA
2
0.4 V
V
OL1
Output low voltage, port 0, ALE, PSEN
8, 7
VCC = 4.5 V
IOL = 3.2 mA
2
0.4 V
V
OH
Output high voltage, ports 1, 2, 3
3
VCC = 4.5 V
IOH = –30 µA
VCC – 0.7 V
V
OH1
Output high voltage (port 0 in external bus mode), ALE9, PSEN
3
VCC = 4.5 V
IOH = –3.2 mA
VCC – 0.7 V
I
IL
Logical 0 input current, ports 1, 2, 3 VIN = 0.4 V –1 –75 µA
I
TL
Logical 1-to-0 transition current, ports 1, 2, 3
6
VIN = 2.0 V See Note 4
–650 µA
I
LI
Input leakage current, port 0 0.45 < VIN < VCC – 0.3 ±10 µA
I
CC
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
T
amb
= 0°C to 70°C 20 100 µA
Figure 40 for conditions)
T
amb
= –40°C to +85°C 125 µA
I
PP
Programming current 11.5 V  VPP 12.5 V 50 mA
R
RST
Internal reset pull-down resistor 40 225 k
C
IO
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
OL
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
OL
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
OH
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
IN
is approximately 2 V .
5. See Figures 37 through 40 for I
CC
test conditions and Figure 36 for I
CC
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
OL
must be externally limited as follows:
Maximum I
OL
per port pin: 15 mA (*NOTE: This is 85°C specification.)
Maximum I
OL
per 8-bit port: 26 mA
Maximum total I
OL
for all outputs: 71 mA
If I
OL
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
33
AC ELECTRICAL CHARACTERISTICS
T
amb
= 0°C to +70°C or –40°C to +85°C, VCC = 5 V ±10%, VSS = 0 V
1, 2, 3
VARIABLE CLOCK
4
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
3.5 33
MHz
t
LHLL
29 ALE pulse width 2t
CLCL
–40 21 ns
t
AVLL
29 Address valid to ALE low t
CLCL
–25 5 ns
t
LLAX
29 Address hold after ALE low t
CLCL
–25 5 ns
t
LLIV
29 ALE low to valid instruction in 4t
CLCL
–65 55 ns
t
LLPL
29 ALE low to PSEN low t
CLCL
–25 5 ns
t
PLPH
29 PSEN pulse width 3t
CLCL
–45 45 ns
t
PLIV
29 PSEN low to valid instruction in 3t
CLCL
–60 30 ns
t
PXIX
29 Input instruction hold after PSEN 0 0 ns
t
PXIZ
29 Input instruction float after PSEN t
CLCL
–25 5 ns
t
AVIV
29 Address to valid instruction in 5t
CLCL
–80 70 ns
t
PLAZ
29 PSEN low to address float 10 10 ns
Data Memory
t
RLRH
30, 31 RD pulse width 6t
CLCL
–100 82 ns
t
WLWH
30, 31 WR pulse width 6t
CLCL
–100 82 ns
t
RLDV
30, 31 RD low to valid data in 5t
CLCL
–90 60 ns
t
RHDX
30, 31 Data hold after RD 0 0 ns
t
RHDZ
30, 31 Data float after RD 2t
CLCL
–28 32 ns
t
LLDV
30, 31 ALE low to valid data in 8t
CLCL
–150 90 ns
t
AVDV
30, 31 Address to valid data in 9t
CLCL
–165 105 ns
t
LLWL
30, 31 ALE low to RD or WR low 3t
CLCL
–50 3t
CLCL
+50 40 140 ns
t
AVWL
30, 31 Address valid to WR low or RD low 4t
CLCL
–75 45 ns
t
QVWX
30, 31 Data valid to WR transition t
CLCL
–30 0 ns
t
WHQX
30, 31 Data hold after WR t
CLCL
–25 5 ns
t
QVWH
31 Data valid to WR high 7t
CLCL
–130 80 ns
t
RLAZ
30, 31 RD low to address float 0 0 ns
t
WHLH
30, 31 RD or WR high to ALE high t
CLCL
–25 t
CLCL
+25 5 55 ns
External Clock
t
CHCX
33 High time 17 t
CLCL–tCLCX
ns
t
CLCX
33 Low time 17 t
CLCL–tCHCX
ns
t
CLCH
33 Rise time 5 ns
t
CHCL
33 Fall time 5 ns
Shift Register
t
XLXL
32 Serial port clock cycle time 12t
CLCL
360 ns
t
QVXH
32 Output data setup to clock rising edge 10t
CLCL
–133 167 ns
t
XHQX
32 Output data hold after clock rising edge 2t
CLCL
–80 50 ns
t
XHDX
32 Input data hold after clock rising edge 0 0 ns
t
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
34
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 .
t
LLPL
=Time for ALE low to PSEN low.
t
PXIZ
ALE
PSEN
PORT 0
PORT 2
A0–A15 A8–A15
A0–A7 A0–A7
t
AVLL
t
PXIX
t
LLAX
INSTR IN
t
LHLL
t
PLPH
t
LLIV
t
PLAZ
t
LLPL
t
AVIV
SU00006
t
PLIV
Figure 29. External Program Memory Read Cycle
ALE
PSEN
PORT 0
PORT 2
RD
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
t
WHLH
t
LLDV
t
LLWL
t
RLRH
t
LLAX
t
RLAZ
t
AVLL
t
RHDX
t
RHDZ
t
AVWL
t
AVDV
t
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
35
t
LLAX
ALE
PSEN
PORT 0
PORT 2
WR
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
t
WHLH
t
LLWL
t
WLWH
t
AVLL
t
AVWL
t
QVWX
t
WHQX
t
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
t
XLXL
t
QVXH
t
XHQX
t
XHDX
t
XHDV
SU00027
1230 4567
Figure 32. Shift Register Mode Timing
VCC–0.5
0.45V
0.7V
CC
0.2VCC–0.1
t
CHCL
t
CLCL
t
CLCH
t
CLCX
t
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
36
VCC–0.5
0.45V
0.2V
CC
+0.9
0.2V
CC
–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
V
LOAD
V
LOAD
+0.1V
V
LOAD
–0.1V
V
OH
–0.1V
V
OL
+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
60
50
40
30
20
10
Frequency at XTAL1 (MHz)
I
CC
(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
37
V
CC
P0
EA
RST
XTAL1
XTAL2
V
SS
V
CC
V
CC
V
CC
I
CC
(NC)
CLOCK SIGNAL
SU00719
Figure 37. ICC Test Condition, Active Mode
All other pins are disconnected
V
CC
P0 EA
RST
XTAL1
XTAL2
V
SS
V
CC
V
CC
I
CC
(NC)
CLOCK SIGNAL
SU00720
Figure 38. ICC Test Condition, Idle Mode
All other pins are disconnected
VCC–0.5
0.45V
0.7V
CC
0.2VCC–0.1
t
CHCL
t
CLCL
t
CLCH
t
CLCX
t
CHCX
SU00009
Figure 39. Clock Signal Waveform for ICC Tests in Active and Idle Modes
t
CLCH
= t
CHCL
= 5 ns
V
CC
P0
EA
RST
XTAL1
XTAL2
V
SS
V
CC
V
CC
I
CC
(NC)
SU00016
Figure 40. ICC Test Condition, Power Down Mode
All other pins are disconnected. V
CC
= 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
38
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
PP
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
39
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
40
+12V
+5V TxD RxD V
SS
V
PP
V
CC
TxD RxD
RST
XTAL2
XTAL1
SU01042
V
SS
V
CC
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
SS
, 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
PP
supply should be adequately decoupled and provide a
minimum 50mA. V
PP
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
41
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
42
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
43
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
44
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
45
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
1
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
46
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
47
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
48
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
49
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
50
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
All rights reserved. Printed in U.S.A.
Date of release: 10-99
Document order number: 9397-750-06605
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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.
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