PHILIPS P89C51RD+

INTEGRATED CIRCUITS
P89C51RC+/P89C51RD+
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
Product specification
Replaces 89C51RC+/RD+ of 1999 Apr 01
(see Notes 1 and 2 on page 2)
Supersedes data of 1999 Apr 01
IC28 Data Handbook
1999 Oct 27
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
DESCRIPTION
FEATURES
• 80C51 Central Processing Unit
• On-chip FLASH Program Memory with In-System Programming
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.
(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
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)
– Framing error detection
– Automatic address recognition
• Power control modes
89C51RC+
32 k
512
Yes
1024
Yes
– Clock can be stopped and resumed
– Idle mode
89C51RD+
64 k
P89C51RC+/P89C51RD+
– Power down mode
• Programmable clock out
• Second DPTR register
• Asynchronous port reset
• Low EMI (inhibit ALE)
• Watchdog timer
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.
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.
5V
0 to 33
SOT129-1
P89C51RC+IA
P89C51RD+IA
0 to +70,
44-Pin Plastic Leaded Chip Carrier
5V
0 to 33
SOT187-2
P89C51RC+IB
P89C51RD+IB
0 to +70,
44-Pin Plastic Quad Flat Pack
5V
0 to 33
QFP441
P89C51RC+JN
P89C51RD+JN
–40 to +85,
40-Pin Plastic Dual In-line Pkg.
5V
0 to 33
SOT129-1
P89C51RC+JA
P89C51RD+JA
–40 to +85,
44-Pin Plastic Leaded Chip Carrier
5V
0 to 33
SOT187-2
P89C51RC+JB
P89C51RD+JB
–40 to +85,
44-Pin Plastic Quad Flat Pack
5V
0 to 33
QFP441
NOTE:
1. SOT not assigned for this package outline.
1999 Oct 27
2
853-2149 22593
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
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
P0.0–P0.7
P2.0–P2.7
PORT 0
DRIVERS
PORT 2
DRIVERS
VCC
VSS
RAM ADDR
REGISTER
PORT 0
LATCH
RAM
PORT 2
LATCH
FLASH
8
B
REGISTER
STACK
POINTER
ACC
PROGRAM
ADDRESS
REGISTER
TMP1
TMP2
BUFFER
ALU
SFRs
TIMERS
PSW
PC
INCREMENTER
P.C.A.
8
16
PSEN
ALE
EAVPP
TIMING
AND
CONTROL
RST
INSTRUCTION
REGISTER
PROGRAM
COUNTER
PD
DPTR’S
MULTIPLE
PORT 1
LATCH
PORT 3
LATCH
PORT 1
DRIVERS
PORT 3
DRIVERS
P1.0–P1.7
P3.0–P3.7
OSCILLATOR
XTAL1
XTAL2
SU01065
1999 Oct 27
3
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
LOGIC SYMBOL
P89C51RC+/P89C51RD+
PLASTIC LEADED CHIP CARRIER PIN FUNCTIONS
VCC
VSS
6
1
40
XTAL1
7
39
PORT 0
ADDRESS AND
DATA BUS
LCC
XTAL2
T2
T2EX
PORT 1
RST
EA/VPP
PSEN
PORT 2
RxD
TxD
INT0
INT1
T0
T1
WR
RD
29
18
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
ALE/PROG
PORT 3
SECONDARY FUNCTIONS
17
ADDRESS BUS
SU00830
PIN CONFIGURATIONS
Function
NIC*
P1.0/T2
P1.1/T2EX
P1.2/ECI
P1.3/CEX0
P1.4/CEX1
P1.5/CEX2
P1.6/CEX3
P1.7/CEX4
RST
P3.0/RxD
NIC*
P3.1/TxD
P3.2/INT0
P3.3/INT1
Pin
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
28
Pin
31
32
33
34
35
36
37
38
39
40
41
42
43
44
Function
P3.4/T0
P3.5/T1
P3.6/WR
P3.7/RD
XTAL2
XTAL1
VSS
NIC*
P2.0/A8
P2.1/A9
P2.2/A10
P2.3/A11
P2.4/A12
P2.5/A13
P2.6/A14
* NO INTERNAL CONNECTION
Function
P2.7/A15
PSEN
ALE
NIC*
EA/VPP
P0.7/AD7
P0.6/AD6
P0.5/AD5
P0.4/AD4
P0.3/AD3
P0.2/AD2
P0.1/AD1
P0.0/AD0
VCC
SU00890
DUAL IN-LINE PACKAGE PIN FUNCTIONS
T2/P1.0 1
PLASTIC QUAD FLAT PACK
PIN FUNCTIONS
40 VCC
T2EX/P1.1 2
39 P0.0/AD0
ECI/P1.2 3
38 P0.1/AD1
CEX0/P1.3 4
37 P0.2/AD2
CEX1/P1.4 5
36 P0.3/AD3
CEX2/P1.5 6
35 P0.4/AD4
CEX3/P1.6 7
34 P0.5/AD5
CEX4/P1.7 8
33 P0.6/AD6
44
34
1
33
PQFP
11
32 P0.7/AD7
RST 9
RxD/P3.0 10
TxD/P3.1 11
DUAL
IN-LINE
PACKAGE
12
31 EA/VPP
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
30 ALE
INT0/P3.2 12
29 PSEN
INT1/P3.3 13
28 P2.7/A15
T0/P3.4 14
27 P2.6/A14
T1/P3.5 15
26 P2.5/A13
WR/P3.6 16
25 P2.4/A12
RD/P3.7 17
24 P2.3/A11
XTAL2 18
23 P2.2/A10
XTAL1 19
22 P2.1/A9
VSS 20
21 P2.0/A8
Function
P1.5/CEX2
P1.6/CEX3
P1.7/CEX4
RST
P3.0/RxD
NIC*
P3.1/TxD
P3.2/INT0
P3.3/INT1
P3.4/T0
P3.5/T1
P3.6/WR
P3.7/RD
XTAL2
XTAL1
Pin
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
* NO INTERNAL CONNECTION
SU00888
1999 Oct 27
23
4
22
Function
VSS
NIC*
P2.0/A8
P2.1/A9
P2.2/A10
P2.3/A11
P2.4/A12
P2.5/A13
P2.6/A14
P2.7/A15
PSEN
ALE
NIC*
EA/VPP
P0.7/AD7
Pin
31
32
33
34
35
36
37
38
39
40
41
42
43
44
Function
P0.6/AD6
P0.5/AD5
P0.4/AD4
P0.3/AD3
P0.2/AD2
P0.1/AD1
P0.0/AD0
VCC
NIC*
P1.0/T2
P1.1/T2EX
P1.2/ECI
P1.3/CEX0
P1.4/CEX1
SU00891
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
PIN DESCRIPTIONS
PIN NUMBER
MNEMONIC
DIP
LCC
QFP
TYPE
NAME AND FUNCTION
VSS
20
22
16
I
Ground: 0 V reference.
VCC
40
44
38
I
Power Supply: This is the power supply voltage for normal, idle, and power-down operation.
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.
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: IIL).
1
2
3
4
5
6
7
8
2
3
4
5
6
7
8
9
40
41
42
43
44
1
2
3
I/O
I
I
I/O
I/O
I/O
I/O
I/O
T2 (P1.0): Timer/Counter 2 external count input/Clockout (see Programmable Clock-Out)
T2EX (P1.1): Timer/Counter 2 Reload/Capture/Direction Control
ECI (P1.2): External Clock Input to the PCA
CEX0 (P1.3): Capture/Compare External I/O for PCA module 0
CEX1 (P1.4): Capture/Compare External I/O for PCA module 1
CEX2 (P1.5): Capture/Compare External I/O for PCA module 2
CEX3 (P1.6): Capture/Compare External I/O for PCA module 3
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: IIL). Port 2 emits the high-order address byte
during fetches from external program memory and during accesses to external data memory
that use 16-bit addresses (MOVX @DPTR). In this application, it uses strong internal
pull-ups when emitting 1s. During accesses to external data memory that use 8-bit addresses
(MOV @Ri), port 2 emits the contents of the P2 special function register.
P3.0–P3.7
10–17
11,
13–19
5,
7–13
I/O
10
11
12
13
14
15
16
17
11
13
14
15
16
17
18
19
5
7
8
9
10
11
12
13
I
O
I
I
I
I
O
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: IIL). Port 3 also serves the special features of the
89C51RX+ family, as listed below:
RxD (P3.0): Serial input port
TxD (P3.1): Serial output port
INT0 (P3.2): External interrupt
INT1 (P3.3): External interrupt
T0 (P3.4): Timer 0 external input
T1 (P3.5): Timer 1 external input
WR (P3.6): External data memory write strobe
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 VSS permits a power-on reset using only an external capacitor
to VCC.
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.
P0.0–0.7
P1.0–P1.7
Alternate functions for 89C51RX+ Port 1 include:
1999 Oct 27
5
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
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/VPP
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 VPP) at any time must not be higher than VCC + 0.5 V or VSS – 0.5 V,
respectively.
1999 Oct 27
6
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
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
–
GF2
0
–
DPS
xx0x00x0B
F4
F3
F2
F1
F0
AUXR1# 2
Auxiliary 1
A2H
–
–
ENBOOT
B*
B register
F0H
F7
F6
F5
CCAP0H#
CCAP1H#
CCAP2H#
CCAP3H#
CCAP4H#
CCAP0L#
CCAP1L#
CCAP2L#
CCAP3L#
CCAP4L#
Module 0 Capture High
Module 1 Capture High
Module 2 Capture High
Module 3 Capture High
Module 4 Capture High
Module 0 Capture Low
Module 1 Capture Low
Module 2 Capture Low
Module 3 Capture Low
Module 4 Capture Low
FAH
FBH
FCH
FDH
FEH
EAH
EBH
ECH
EDH
EEH
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
00H
xxxxxxxxB
xxxxxxxxB
xxxxxxxxB
xxxxxxxxB
xxxxxxxxB
xxxxxxxxB
xxxxxxxxB
xxxxxxxxB
xxxxxxxxB
xxxxxxxxB
CCON*#
CH#
CL#
PCA Counter Control
PCA Counter High
PCA Counter Low
D8H
F9H
E9H
CF
CR
–
CCF4
CCF3
CCF2
CCF1
CCF0
00x00000B
00H
00H
CMOD#
PCA Counter Mode
D9H
CIDL
WDTE
–
–
–
CPS1
CPS0
ECF
00xxx000B
DPTR:
DPH
DPL
Data Pointer (2 bytes)
Data Pointer High
Data Pointer Low
83H
82H
IE*
Interrupt Enable
A8H
00H
00H
AF
AE
AD
AC
AB
AA
A9
A8
EA
EC
BF
BE
ET2
ES
ET1
EX1
ET0
EX0
BD
BC
BB
BA
B9
B8
–
PPC
PT2
PS
PT1
PX1
PT0
PX0
IP*
Interrupt Priority
B8H
B7
B6
B5
B4
B3
B2
B1
B0
IPH#
Interrupt Priority High
B7H
–
PPCH
PT2H
PSH
PT1H
PX1H
PT0H
PX0H
87
86
85
84
83
82
81
80
P0*
Port 0
80H
AD7
AD6
AD5
AD4
AD3
AD2
AD1
AD0
97
96
95
94
93
92
91
90
P1*
Port 1
90H
CEX4
CEX3
CEX2
CEX1
CEX0
ECI
T2EX
T2
A7
A6
A5
A4
A3
A2
A1
A0
AD15
AD14
AD13
AD12
AD11
AD10
AD9
AD8
B7
B6
B5
B4
B3
B2
B1
B0
RD
WR
T1
T0
INT1
INT0
TxD
RxD
P2*
P3*
Port 2
Port 3
A0H
B0H
00H
x0000000B
x0000000B
FFH
FFH
FFH
FFH
PCON#1
Power 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.
1999 Oct 27
7
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
Table 1. 89C51RC+/RD+ Special Function Registers (Continued)
DESCRIPTION
DIRECT
ADDRESS
PSW*
Program Status Word
D0H
RACAP2H#
RACAP2L#
Timer 2 Capture High
Timer 2 Capture Low
CBH
CAH
00H
00H
SADDR#
SADEN#
Slave Address
Slave Address Mask
A9H
B9H
00H
00H
SBUF
Serial Data Buffer
99H
SYMBOL
BIT ADDRESS, SYMBOL, OR ALTERNATIVE PORT FUNCTION
MSB
LSB
D7
D6
D5
D4
D3
D2
D1
D0
CY
AC
F0
RS1
RS0
OV
–
P
RESET
VALUE
000000x0B
xxxxxxxxB
9F
9E
9D
9C
9B
9A
99
98
SM0/FE
SM1
SM2
REN
TB8
RB8
TI
RI
SCON*
Serial Control
98H
SP
Stack Pointer
81H
8F
8E
8D
8C
8B
8A
89
88
TCON*
Timer Control
88H
TF1
TR1
TF0
TR0
IE1
IT1
IE0
IT0
CF
CE
CD
CC
CB
CA
C9
C8
T2CON*
Timer 2 Control
C8H
TF2
EXF2
RCLK
TCLK
EXEN2
TR2
C/T2
CP/RL2
T2MOD#
Timer 2 Mode Control
C9H
–
–
–
–
–
–
T2OE
DCEN
TH0
TH1
TH2#
TL0
TL1
TL2#
Timer High 0
Timer High 1
Timer High 2
Timer Low 0
Timer Low 1
Timer Low 2
8CH
8DH
CDH
8AH
8BH
CCH
TMOD
Timer Mode
89H
00H
07H
00H
00H
xxxxxx00B
00H
00H
00H
00H
00H
00H
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.
OSCILLATOR CHARACTERISTICS
RESET
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.
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
VCC 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 VIH1 (min.) is applied to RESET.
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.
1999 Oct 27
The value on the EA pin is latched when RST is deasserted and has
no further effect.
8
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
LOW POWER MODES
P89C51RC+/P89C51RD+
Design Consideration
• When the idle mode is terminated by a hardware reset, the device
Stop Clock Mode
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.
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
ONCE 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.
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.
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 VCC to
the minimum specified operating voltages before the Power Down
Mode is terminated.
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.
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 configure the Timer/Counter 2 as a clock generator, bit C/T2 (in
T2CON) must be cleared and bit T20E in T2MOD must be set. Bit
TR2 (T2CON.2) also must be set to start the timer.
To properly terminate Power Down the reset or external interrupt
should not be executed before VCC is restored to its normal
operating level and must be held active long enough for the
oscillator to restart and stabilize (normally less than 10ms).
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:
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.
4
Oscillator Frequency
(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.
POWER OFF FLAG
The Power Off Flag (POF) is set by on-chip circuitry when the VCC
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 VCC
level must remain above 3V for the POF to remain unaffected by
the VCC level.
Table 2. External Pin Status During Idle and Power-Down Mode
MODE
PROGRAM MEMORY
ALE
PSEN
Idle
Internal
1
Idle
External
1
Power-down
Internal
0
Power-down
External
0
1999 Oct 27
PORT 0
PORT 1
1
Data
1
Float
0
0
9
PORT 2
PORT 3
Data
Data
Data
Data
Address
Data
Data
Data
Data
Data
Float
Data
Data
Data
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
Figure 3). When reset is applied the DCEN=0 which means Timer 2
will default to counting up. If DCEN bit is set, Timer 2 can count up
or down depending on the value of the T2EX pin.
TIMER 2 OPERATION
Timer 2
Timer 2 is a 16-bit Timer/Counter which can operate as either an
event timer or an event counter, as selected by C/T2* in the special
function register T2CON (see Figure 1). Timer 2 has three operating
modes: Capture, Auto-reload (up or down counting), and Baud Rate
Generator, which are selected by bits in the T2CON as shown in
Table 3.
Figure 4 shows Timer 2 which will count up automatically since
DCEN=0. In this mode there are two options selected by bit EXEN2
in T2CON register. If EXEN2=0, then Timer 2 counts up to 0FFFFH
and sets the TF2 (Overflow Flag) bit upon overflow. This causes the
Timer 2 registers to be reloaded with the 16-bit value in RCAP2L
and RCAP2H. The values in RCAP2L and RCAP2H are preset by
software means.
Capture Mode
In the capture mode there are two options which are selected by bit
EXEN2 in T2CON. If EXEN2=0, then timer 2 is a 16-bit timer or
counter (as selected by C/T2* in T2CON) which, upon overflowing
sets bit TF2, the timer 2 overflow bit. This bit can be used to
generate an interrupt (by enabling the Timer 2 interrupt bit in the
IE register). If EXEN2= 1, Timer 2 operates as described above, but
with the added feature that a 1- to -0 transition at external input
T2EX causes the current value in the Timer 2 registers, TL2 and
TH2, to be captured into registers RCAP2L and RCAP2H,
respectively. In addition, the transition at T2EX causes bit EXF2 in
T2CON to be set, and EXF2 like TF2 can generate an interrupt
(which vectors to the same location as Timer 2 overflow interrupt.
The Timer 2 interrupt service routine can interrogate TF2 and EXF2
to determine which event caused the interrupt). The capture mode is
illustrated in Figure 2 (There is no reload value for TL2 and TH2 in
this mode. Even when a capture event occurs from T2EX, the
counter keeps on counting T2EX pin transitions or osc/12 pulses.).
If EXEN2=1, then a 16-bit reload can be triggered either by an
overflow or by a 1-to-0 transition at input T2EX. This transition also
sets the EXF2 bit. The Timer 2 interrupt, if enabled, can be
generated when either TF2 or EXF2 are 1.
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.
Auto-Reload Mode (Up or Down Counter)
The external flag EXF2 toggles when Timer 2 underflows or
overflows. This EXF2 bit can be used as a 17th bit of resolution if
needed. The EXF2 flag does not generate an interrupt in this mode
of operation.
In the 16-bit auto-reload mode, Timer 2 can be configured (as either
a timer or counter [C/T2* in T2CON]) then programmed to count up
or down. The counting direction is determined by bit DCEN (Down
Counter Enable) which is located in the T2MOD register (see
(MSB)
TF2
(LSB)
EXF2
RCLK
TCLK
EXEN2
TR2
C/T2
CP/RL2
Symbol
Position
Name and Significance
TF2
T2CON.7
EXF2
T2CON.6
RCLK
T2CON.5
TCLK
T2CON.4
EXEN2
T2CON.3
TR2
C/T2
T2CON.2
T2CON.1
CP/RL2
T2CON.0
Timer 2 overflow flag set by a Timer 2 overflow and must be cleared by software. TF2 will not be set
when either RCLK or TCLK = 1.
Timer 2 external flag set when either a capture or reload is caused by a negative transition on T2EX and
EXEN2 = 1. When Timer 2 interrupt is enabled, EXF2 = 1 will cause the CPU to vector to the Timer 2
interrupt routine. EXF2 must be cleared by software. EXF2 does not cause an interrupt in up/down
counter mode (DCEN = 1).
Receive clock flag. When set, causes the serial port to use Timer 2 overflow pulses for its receive clock
in modes 1 and 3. RCLK = 0 causes Timer 1 overflow to be used for the receive clock.
Transmit clock flag. When set, causes the serial port to use Timer 2 overflow pulses for its transmit clock
in modes 1 and 3. TCLK = 0 causes Timer 1 overflows to be used for the transmit clock.
Timer 2 external enable flag. When set, allows a capture or reload to occur as a result of a negative
transition on T2EX if Timer 2 is not being used to clock the serial port. EXEN2 = 0 causes Timer 2 to
ignore events at T2EX.
Start/stop control for Timer 2. A logic 1 starts the timer.
Timer or counter select. (Timer 2)
0 = Internal timer (OSC/12)
1 = External event counter (falling edge triggered).
Capture/Reload flag. When set, captures will occur on negative transitions at T2EX if EXEN2 = 1. When
cleared, auto-reloads will occur either with Timer 2 overflows or negative transitions at T2EX when
EXEN2 = 1. When either RCLK = 1 or TCLK = 1, this bit is ignored and the timer is forced to auto-reload
on Timer 2 overflow.
SU00728
Figure 1. Timer/Counter 2 (T2CON) Control Register
1999 Oct 27
10
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
Table 3. Timer 2 Operating Modes
RCLK + TCLK
CP/RL2
TR2
0
0
1
16-bit Auto-reload
0
1
1
16-bit Capture
1
X
1
Baud rate generator
X
X
0
(off)
OSC
MODE
÷ 12
C/T2 = 0
TL2
(8-bits)
TH2
(8-bits)
TF2
C/T2 = 1
T2 Pin
Control
TR2
Capture
Transition
Detector
Timer 2
Interrupt
RCAP2L
RCAP2H
T2EX Pin
EXF2
Control
EXEN2
SU00066
Figure 2. Timer 2 in Capture Mode
T2MOD
Address = 0C9H
Reset Value = XXXX XX00B
Not Bit Addressable
Bit
*
—
—
—
—
—
—
T2OE
DCEN
7
6
5
4
3
2
1
0
Symbol
Function
—
Not implemented, reserved for future use.*
T2OE
Timer 2 Output Enable bit.
DCEN
Down Count Enable bit. When set, this allows Timer 2 to be configured as an up/down counter.
User software should not write 1s to reserved bits. These bits may be used in future 8051 family products to invoke new features.
In that case, the reset or inactive value of the new bit will be 0, and its active value will be 1. The value read from a reserved bit is
indeterminate.
SU00729
Figure 3. Timer 2 Mode (T2MOD) Control Register
1999 Oct 27
11
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
÷ 12
OSC
C/T2 = 0
TL2
(8-BITS)
TH2
(8-BITS)
C/T2 = 1
T2 PIN
CONTROL
TR2
RELOAD
TRANSITION
DETECTOR
RCAP2L
RCAP2H
TF2
TIMER 2
INTERRUPT
T2EX PIN
EXF2
CONTROL
SU00067
EXEN2
Figure 4. Timer 2 in Auto-Reload Mode (DCEN = 0)
(DOWN COUNTING RELOAD VALUE)
FFH
FFH
TOGGLE
EXF2
OSC
÷12
C/T2 = 0
OVERFLOW
TL2
T2 PIN
TH2
TF2
INTERRUPT
C/T2 = 1
CONTROL
TR2
COUNT
DIRECTION
1 = UP
0 = DOWN
RCAP2L
RCAP2H
(UP COUNTING RELOAD VALUE)
Figure 5. Timer 2 Auto Reload Mode (DCEN = 1)
1999 Oct 27
12
T2EX PIN
SU00730
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
Timer 1
Overflow
÷2
NOTE: OSC. Freq. is divided by 2, not 12.
“0”
÷2
OSC
“1”
C/T2 = 0
SMOD
TL2
(8-bits)
“1”
TH2
(8-bits)
“0”
RCLK
C/T2 = 1
T2 Pin
Control
÷ 16
“1”
TR2
Reload
Transition
Detector
RCAP2L
T2EX Pin
EXF2
RCAP2H
RX Clock
“0”
TCLK
÷ 16
TX Clock
Timer 2
Interrupt
Control
EXEN2
Note availability of additional external interrupt.
SU00068
Figure 6. Timer 2 in Baud Rate Generator Mode
Table 4.
The baud rates in modes 1 and 3 are determined by Timer 2’s
overflow rate given below:
Timer 2 Generated Commonly Used
Baud Rates
Modes 1 and 3 Baud Rates + Timer 2 Overflow Rate
16
Timer 2
Ba d Rate
Baud
Osc Freq
375 K
9.6 K
2.8 K
2.4 K
1.2 K
300
110
300
110
12 MHz
12 MHz
12 MHz
12 MHz
12 MHz
12 MHz
12 MHz
6 MHz
6 MHz
RCAP2H
RCAP2L
FF
FF
FF
FF
FE
FB
F2
FD
F9
FF
D9
B2
64
C8
1E
AF
8F
57
The timer can be configured for either “timer” or “counter” operation.
In many applications, it is configured for “timer” operation (C/T2*=0).
Timer operation is different for Timer 2 when it is being used as a
baud rate generator.
Usually, as a timer it would increment every machine cycle (i.e., 1/12
the oscillator frequency). As a baud rate generator, it increments
every state time (i.e., 1/2 the oscillator frequency). Thus the baud
rate formula is as follows:
Modes 1 and 3 Baud Rates =
Oscillator Frequency
[32 [65536 * (RCAP2H, RCAP2L)]]
Baud Rate Generator Mode
Where: (RCAP2H, RCAP2L)= The content of RCAP2H and
RCAP2L taken as a 16-bit unsigned integer.
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.
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.
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.
1999 Oct 27
13
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
If Timer 2 is being clocked internally , the baud rate is:
When Timer 2 is in the baud rate generator mode, one should not try
to read or write TH2 and TL2. As a baud rate generator, Timer 2 is
incremented every state time (osc/2) or asynchronously from pin T2;
under these conditions, a read or write of TH2 or TL2 may not be
accurate. The RCAP2 registers may be read, but should not be
written to, because a write might overlap a reload and cause write
and/or reload errors. The timer should be turned off (clear TR2)
before accessing the Timer 2 or RCAP2 registers.
Baud Rate +
[32
f OSC
[65536 * (RCAP2H, RCAP2L)]]
Where fOSC= Oscillator Frequency
To obtain the reload value for RCAP2H and RCAP2L, the above
equation can be rewritten as:
Table 4 shows commonly used baud rates and how they can be
obtained from Timer 2.
RCAP2H, RCAP2L + 65536 *
ǒ
32
Ǔ
f OSC
Baud Rate
Summary of Baud Rate Equations
Timer/Counter 2 Set-up
Timer 2 is in baud rate generating mode. If Timer 2 is being clocked
through pin T2(P1.0) the baud rate is:
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.
Baud Rate + Timer 2 Overflow Rate
16
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.
1999 Oct 27
14
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
Slave 1
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.
Slave 0
SADDR =
SADEN =
Given
=
1100 0000
1111 1001
1100 0XX0
Slave 1
SADDR =
SADEN =
Given
=
1110 0000
1111 1010
1110 0X0X
Slave 2
SADDR =
SADEN =
Given
=
1110 0000
1111 1100
1110 00XX
In the above example the differentiation among the 3 slaves is in the
lower 3 address bits. Slave 0 requires that bit 0 = 0 and it can be
uniquely addressed by 1110 0110. Slave 1 requires that bit 1 = 0 and
it can be uniquely addressed by 1110 and 0101. Slave 2 requires
that bit 2 = 0 and its unique address is 1110 0011. To select Slaves 0
and 1 and exclude Slave 2 use address 1110 0100, since it is
necessary to make bit 2 = 1 to exclude slave 2.
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.
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.
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:
1999 Oct 27
1100 0000
1111 1110
1100 000X
In a more complex system the following could be used to select
slaves 1 and 2 while excluding slave 0:
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.
SADDR =
SADEN =
Given
=
SADDR =
SADEN =
Given
=
In the above example SADDR is the same and the SADEN data is
used to differentiate between the two slaves. Slave 0 requires a 0 in
bit 0 and it ignores bit 1. Slave 1 requires a 0 in bit 1 and bit 0 is
ignored. A unique address for Slave 0 would be 1100 0010 since
slave 1 requires a 0 in bit 1. A unique address for slave 1 would be
1100 0001 since a 1 in bit 0 will exclude slave 0. Both slaves can be
selected at the same time by an address which has bit 0 = 0 (for
slave 0) and bit 1 = 0 (for slave 1). Thus, both could be addressed
with 1100 0000.
When used for framing error detect the UART looks for missing stop
bits in the communication. A missing bit will set the FE bit in the
SCON register. The FE bit shares the SCON.7 bit with SM0 and the
function of SCON.7 is determined by PCON.6 (SMOD0) (see
Figure 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.
Slave 0
P89C51RC+/P89C51RD+
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.
1100 0000
1111 1101
1100 00X0
15
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
SCON Address = 98H
Reset Value = 0000 0000B
Bit Addressable
SM0/FE
Bit:
SM1
7
6
(SMOD0 = 0/1)*
SM2
REN
TB8
RB8
Tl
Rl
5
4
3
2
1
0
Symbol
Function
FE
Framing Error bit. This bit is set by the receiver when an invalid stop bit is detected. The FE bit is not cleared by valid
frames but should be cleared by software. The SMOD0 bit must be set to enable access to the FE bit.
SM0
Serial Port Mode Bit 0, (SMOD0 must = 0 to access bit SM0)
SM1
Serial Port Mode Bit 1
SM0
SM1
Mode
0
0
1
1
0
1
0
1
0
1
2
3
Description
Baud Rate**
shift register
8-bit UART
9-bit UART
9-bit UART
fOSC/12
variable
fOSC/64 or fOSC/32
variable
SM2
Enables the Automatic Address Recognition feature in Modes 2 or 3. If SM2 = 1 then Rl will not be set unless the
received 9th data bit (RB8) is 1, indicating an address, and the received byte is a Given or Broadcast Address.
In Mode 1, if SM2 = 1 then Rl will not be activated unless a valid stop bit was received, and the received byte is a
Given or Broadcast Address. In Mode 0, SM2 should be 0.
REN
Enables serial reception. Set by software to enable reception. Clear by software to disable reception.
TB8
The 9th data bit that will be transmitted in Modes 2 and 3. Set or clear by software as desired.
RB8
In modes 2 and 3, the 9th data bit that was received. In Mode 1, if SM2 = 0, RB8 is the stop bit that was received.
In Mode 0, RB8 is not used.
Tl
Transmit interrupt flag. Set by hardware at the end of the 8th bit time in Mode 0, or at the beginning of the stop bit in the
other modes, in any serial transmission. Must be cleared by software.
Rl
Receive interrupt flag. Set by hardware at the end of the 8th bit time in Mode 0, or halfway through the stop bit time in
the other modes, in any serial reception (except see SM2). Must be cleared by software.
NOTE:
*SMOD0 is located at PCON6.
**fOSC = oscillator frequency
SU00043
Figure 7. SCON: Serial Port Control Register
1999 Oct 27
16
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
D0
D1
D2
D3
P89C51RC+/P89C51RD+
D4
D5
D6
D7
D8
DATA BYTE
START
BIT
ONLY IN
MODE 2, 3
STOP
BIT
SET FE BIT IF STOP BIT IS 0 (FRAMING ERROR)
SM0 TO UART MODE CONTROL
SM0 / FE
SM1
SM2
REN
SMOD1
SMOD0
–
POF
TB8
GF1
RB8
TI
GF0
PD
RI
SCON
(98H)
IDL
PCON
(87H)
0 : SCON.7 = SM0
1 : SCON.7 = FE
SU01191
Figure 8. UART Framing Error Detection
D0
D1
D2
D3
D4
SM0
SM1
1
1
1
0
D5
SM2
1
D6
D7
D8
REN
TB8
RB8
1
X
TI
RI
SCON
(98H)
RECEIVED ADDRESS D0 TO D7
COMPARATOR
PROGRAMMED ADDRESS
IN UART MODE 2 OR MODE 3 AND SM2 = 1:
INTERRUPT IF REN=1, RB8=1 AND “RECEIVED ADDRESS” = “PROGRAMMED ADDRESS”
– WHEN OWN ADDRESS RECEIVED, CLEAR SM2 TO RECEIVE DATA BYTES
– WHEN ALL DATA BYTES HAVE BEEN RECEIVED: SET SM2 TO WAIT FOR NEXT ADDRESS.
SU00045
Figure 9. UART Multiprocessor Communication, Automatic Address Recognition
1999 Oct 27
17
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
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.
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
INTERRUPT PRIORITY LEVEL
IPH.x
IP.x
0
0
Level 0 (lowest priority)
0
1
Level 1
1
0
Level 2
1
1
Level 3 (highest priority)
Table 7.
Interrupt Table
SOURCE
POLLING PRIORITY
REQUEST BITS
HARDWARE CLEAR?
N
(L)1
Y
(T)2
VECTOR ADDRESS
X0
1
IE0
T0
2
TP0
Y
03H
X1
3
IE1
N (L) Y (T)
13H
T1
4
TF1
Y
1BH
PCA
5
CF, CCFn
n = 0–4
N
33H
SP
6
RI, TI
N
23H
T2
7
TF2, EXF2
N
2BH
0BH
NOTES:
1. L = Level activated
2. T = Transition activated
IE (0A8H)
7
6
5
4
3
2
1
0
EA
EC
ET2
ES
ET1
EX1
ET0
EX0
Enable Bit = 1 enables the interrupt.
Enable Bit = 0 disables it.
BIT
IE.7
SYMBOL
EA
IE.6
IE.5
IE.4
IE.3
IE.2
IE.1
IE.0
EC
ET2
ES
ET1
EX1
ET0
EX0
FUNCTION
Global disable bit. If EA = 0, all interrupts are disabled. If EA = 1, each interrupt can be individually
enabled or disabled by setting or clearing its enable bit.
PCA interrupt enable bit
Timer 2 interrupt enable bit.
Serial Port interrupt enable bit.
Timer 1 interrupt enable bit.
External interrupt 1 enable bit.
Timer 0 interrupt enable bit.
External interrupt 0 enable bit.
SU01037
Figure 10. IE Registers
1999 Oct 27
18
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
IP (0B8H)
P89C51RC+/P89C51RD+
7
6
5
4
3
2
1
0
—
PPC
PT2
PS
PT1
PX1
PT0
PX0
Priority Bit = 1 assigns high priority
Priority Bit = 0 assigns low priority
BIT
IP.7
IP.6
IP.5
IP.4
IP.3
IP.2
IP.1
IP.0
SYMBOL
—
PPC
PT2
PS
PT1
PX1
PT0
PX0
FUNCTION
Not implemented, reserved for future use.
PCA interrupt priority bit
Timer 2 interrupt priority bit.
Serial Port interrupt priority bit.
Timer 1 interrupt priority bit.
External interrupt 1 priority bit.
Timer 0 interrupt priority bit.
External interrupt 0 priority bit.
SU01038
Figure 11. IP Registers
IPH (B7H)
7
6
5
4
3
2
1
0
—
PPCH
PT2H
PSH
PT1H
PX1H
PT0H
PX0H
Priority Bit = 1 assigns higher priority
Priority Bit = 0 assigns lower priority
BIT
IPH.7
IPH.6
IPH.5
IPH.4
IPH.3
IPH.2
IPH.1
IPH.0
SYMBOL
—
PPCH
PT2H
PSH
PT1H
PX1H
PT0H
PX0H
FUNCTION
Not implemented, reserved for future use.
PCA interrupt priority bit
Timer 2 interrupt priority bit high.
Serial Port interrupt priority bit high.
Timer 1 interrupt priority bit high.
External interrupt 1 priority bit high.
Timer 0 interrupt priority bit high.
External interrupt 0 priority bit high.
Figure 12. IPH Registers
1999 Oct 27
19
SU01039
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
be quickly toggled simply by executing an INC AUXR1 instruction
without affecting the GF2 bit.
Reduced EMI Mode
The AO bit (AUXR.0) in the AUXR register when set disables the
ALE output.
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 > VIH on the falling edge of reset. Otherwise, this bit will be
cleared during reset.
Reduced EMI Mode
AUXR (8EH)
7
6
5
4
3
2
1
0
–
–
–
–
–
–
EXTRAM
AO
AUXR.1
AUXR.0
EXTRAM
AO
P89C51RC+/P89C51RD+
DPS
Turns off ALE output.
BIT0
AUXR1
DPTR0
Dual DPTR
DPH
(83H)
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.
DPL
(82H)
EXTERNAL
DATA
MEMORY
SU00745A
Figure 13.
• New Register Name: AUXR1#
• SFR Address: A2H
• Reset Value: xx0x00x0B
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:
AUXR1 (A2H)
7
6
5
4
3
2
1
0
–
–
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.
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.
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
1999 Oct 27
DPTR1
20
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
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.
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.
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 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 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.
The watchdog timer function is implemented in module 4 (see
Figure 24).
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.
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
16 BITS
MODULE 0
P1.3/CEX0
MODULE 1
P1.4/CEX1
MODULE 2
P1.5/CEX2
MODULE 3
P1.6/CEX3
MODULE 4
P1.7/CEX4
16 BITS
PCA TIMER/COUNTER
TIME BASE FOR PCA MODULES
MODULE FUNCTIONS:
16-BIT CAPTURE
16-BIT TIMER
16-BIT HIGH SPEED OUTPUT
8-BIT PWM
WATCHDOG TIMER (MODULE 4 ONLY)
SU00032
Figure 14. Programmable Counter Array (PCA)
1999 Oct 27
21
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
TO PCA
MODULES
OSC/12
OVERFLOW
OSC/4
CH
INTERRUPT
CL
16–BIT UP COUNTER
TIMER 0
OVERFLOW
EXTERNAL INPUT
(P1.2/ECI)
00
01
10
11
DECODE
IDLE
CIDL
CF
WDTE
––
––
––
CPS1
CPS0
ECF
CMOD
(D9H)
CR
––
CCF4
CCF3
CCF2
CCF1
CCF0
CCON
(D8H)
SU00033
Figure 15. PCA Timer/Counter
CF
CR
––
CCF4
CCF3
CCF2
CCF1
CCF0
CCON
(D8H)
PCA TIMER/COUNTER
MODULE 0
IE.6
EC
IE.7
EA
TO
INTERRUPT
PRIORITY
DECODER
MODULE 1
MODULE 2
MODULE 3
MODULE 4
CMOD.0
ECF
CCAPMn.0
ECCFn
SU00034
Figure 16. PCA Interrupt System
1999 Oct 27
22
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
CMOD Address = OD9H
Reset Value = 00XX X000B
CIDL
WDTE
–
–
–
CPS1
7
6
5
4
3
2
Bit:
CPS0
1
ECF
0
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 Timer 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
1
1
ECF
0
1
0
1
Internal clock, fOSC ÷ 12
Internal clock, fOSC ÷ 4
Timer 0 overflow
External clock at ECI/P1.2 pin (max. rate = fOSC ÷ 8)
0
1
2
3
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.
** fOSC = oscillator frequency
SU00035
Figure 17. CMOD: PCA Counter Mode Register
CCON Address = OD8H
Reset Value = 00X0 0000B
Bit Addressable
Bit:
CF
CR
–
CCF4
CCF3
CCF2
CCF1
CCF0
7
6
5
4
3
2
1
0
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
Figure 18. CCON: PCA Counter Control Register
1999 Oct 27
23
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
CCAPMn Address
CCAPM0
CCAPM1
CCAPM2
CCAPM3
CCAPM4
P89C51RC+/P89C51RD+
0DAH
0DBH
0DCH
0DDH
0DEH
Reset Value = X000 0000B
Not Bit Addressable
Bit:
–
ECOMn
CAPPn
CAPNn
MATn
TOGn
PWMn
ECCFn
7
6
5
4
3
2
1
0
Symbol
Function
–
ECOMn
CAPPn
CAPNn
MATn
Not implemented, reserved for future use*.
Enable Comparator. ECOMn = 1 enables the comparator function.
Capture Positive, CAPPn = 1 enables positive edge capture.
Capture Negative, CAPNn = 1 enables negative edge capture.
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.
Toggle. When TOGn = 1, a match of the PCA counter with this module’s compare/capture register causes the CEXn
pin to toggle.
Pulse Width Modulation Mode. PWMn = 1 enables the CEXn pin to be used as a pulse width modulated output.
Enable CCF interrupt. Enables compare/capture flag CCFn in the CCON register to generate an interrupt.
TOGn
PWMn
ECCFn
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
Figure 19. CCAPMn: PCA Modules Compare/Capture Registers
–
ECOMn
CAPPn
CAPNn
MATn
TOGn
PWMn
ECCFn
X
0
0
0
0
0
0
0
No operation
MODULE FUNCTION
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.
High Speed Output Mode
In this mode the CEX output (on port 1) associated with the PCA
module will toggle each time a match occurs between the PCA
counter and the module’s capture registers. To activate this mode
the TOG, MAT, and ECOM bits in the module’s CCAPMn SFR must
be set (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.
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).
1999 Oct 27
24
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
CF
CR
––
CCF4
P89C51RC+/P89C51RD+
CCF3
CCF2
CCF1
CCON
(D8H)
CCF0
PCA INTERRUPT
(TO CCFn)
PCA TIMER/COUNTER
CH
CL
CCAPnH
CCAPnL
CAPTURE
CEXn
––
ECOMn
CAPPn
CAPNn
MATn
TOGn
PWMn
0
0
0
0
ECCFn
CCAPMn, n= 0 to 4
(DAH – DEH)
SU00749
Figure 21. PCA Capture Mode
CF
WRITE TO
CCAPnH
––
CCF4
CCF3
CCF2
CCF1
CCF0
CCON
(D8H)
RESET
CCAPnH
WRITE TO
CCAPnL
0
CR
PCA INTERRUPT
CCAPnL
(TO CCFn)
1
ENABLE
MATCH
16–BIT COMPARATOR
CH
CL
PCA TIMER/COUNTER
––
ECOMn
CAPPn
CAPNn
0
0
MATn
TOGn
PWMn
0
0
ECCFn
CCAPMn, n= 0 to 4
(DAH – DEH)
SU00750
Figure 22. PCA Compare Mode
1999 Oct 27
25
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
CF
WRITE TO
CCAPnH
CR
CCF4
CCF3
CCF2
CCF1
CCON
(D8H)
CCF0
RESET
CCAPnH
WRITE TO
CCAPnL
0
––
P89C51RC+/P89C51RD+
PCA INTERRUPT
CCAPnL
(TO CCFn)
1
MATCH
ENABLE
16–BIT COMPARATOR
TOGGLE
CH
CEXn
CL
PCA TIMER/COUNTER
––
ECOMn
CAPPn
CAPNn
0
0
MATn
TOGn
PWMn
1
CCAPMn, n: 0..4
(DAH – DEH)
ECCFn
0
SU00751
Figure 23. PCA High Speed Output Mode
CCAPnH
CCAPnL
0
CL < CCAPnL
ENABLE
8–BIT
COMPARATOR
CEXn
CL >= CCAPnL
1
CL
OVERFLOW
PCA TIMER/COUNTER
––
ECOMn
CAPPn
CAPNn
MATn
TOGn
0
0
0
0
PWMn
ECCFn
CCAPMn, n: 0..4
(DAH – DEH)
0
SU00752
Figure 24. PCA PWM Mode
1999 Oct 27
26
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
CIDL
WRITE TO
CCAP4H
––
––
––
CPS1
CPS0
ECF
CMOD
(D9H)
RESET
CCAP4H
WRITE TO
CCAP4L
0
WDTE
P89C51RC+/P89C51RD+
CCAP4L
MODULE 4
1
ENABLE
MATCH
16–BIT COMPARATOR
CH
RESET
CL
PCA TIMER/COUNTER
––
ECOMn
CAPPn
CAPNn
MATn
0
0
1
TOGn
X
PWMn
ECCFn
0
X
CCAPM4
(DEH)
SU00832
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.
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 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.
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.
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,
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
216 count of 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.
1999 Oct 27
27
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
INIT_WATCHDOG:
MOV CCAPM4, #4CH
MOV CCAP4L, #0FFH
MOV CCAP4H, #0FFH
ORL CMOD, #40H
;
;
;
;
;
;
;
;
P89C51RC+/P89C51RD+
Module 4 in compare mode
Write to low byte first
Before PCA timer counts up to
FFFF Hex, these compare values
must be changed
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
1999 Oct 27
28
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
For example:
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 bytes Special Function Register (SFR), and 256 bytes
(768 for RD+) expanded RAM (ERAM).
where R0 contains 0A0H, accesses the data byte at address 0A0H,
rather than P2 (whose address is 0A0H).
The four segments are:
1. The Lower 128 bytes of RAM (addresses 00H to 7FH) are
directly and indirectly addressable.
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.
MOV @R0,#data
2. The Upper 128 bytes of RAM (addresses 80H to FFH) are
indirectly addressable only.
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,
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.
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.
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.
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).
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.
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
Address = 8EH
Reset Value = xxxx xx00B
Not Bit Addressable
—
—
—
—
—
—
EXTRAM
AO
7
6
5
4
3
2
1
0
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
Figure 27. AUXR: Auxiliary Register (RX+ only)
1999 Oct 27
29
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
ÉÉÉÉÉ
ÉÉÉÉÉ
ÉÉÉÉÉ
ÉÉÉÉÉ
ÉÉÉÉÉ
P89C51RC+/P89C51RD+
2FF
(89C51RD+)
FF
FF
UPPER
128 BYTES
INTERNAL RAM
ERAM
256 BYTES
FFFF
FF
80
SPECIAL
FUNCTION
REGISTER
EXTERNAL
DATA
MEMORY
80
LOWER
128 BYTES
INTERNAL RAM
300 (89C51RD+)
00
00
00
0100
0000
SU00885
Figure 28. Internal and External Data Memory Address Space with EXTRAM = 0
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.
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 × TOSC, where TOSC = 1/fOSC. To
make the best use of the WDT, it should be serviced in those
sections of code that will periodically be executed within the time
required to prevent a WDT reset.
1999 Oct 27
30
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
ABSOLUTE MAXIMUM RATINGS1, 2, 3
PARAMETER
Operating temperature under bias
Storage temperature range
Voltage on EA/VPP pin to VSS
Voltage on any other pin to VSS
Maximum IOL per I/O pin
RATING
UNIT
0 to +70 or –40 to +85
°C
–65 to +150
°C
0 to +13.0
V
–0.5 to +6.5
V
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 VSS unless otherwise
noted.
1999 Oct 27
31
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
DC ELECTRICAL CHARACTERISTICS
Tamb = 0°C to +70°C or –40°C to +85°C; 5 V ±10%; VSS = 0 V
SYMBOL
TEST
CONDITIONS
PARAMETER
VIL
Input low voltage
VIH
Input high voltage (ports 0, 1, 2, 3, EA)
VIH1
Input high voltage, XTAL1, RST
VOL
Output low voltage, ports 1, 2, 3 8
VOL1
MIN
TYP1
UNIT
MAX
–0.5
0.2VCC–0.1
V
0.2VCC+0.9
VCC+0.5
V
0.7VCC
VCC+0.5
V
VCC = 4.5 V
IOL = 1.6 mA2
0.4
V
Output low voltage, port 0, ALE, PSEN 8, 7
VCC = 4.5 V
IOL = 3.2 mA2
0.4
V
VOH
Output high voltage, ports 1, 2, 3 3
VCC = 4.5 V
IOH = –30 µA
VCC – 0.7
V
VOH1
Output high voltage (port 0 in external bus mode),
ALE9, PSEN3
VCC = 4.5 V
IOH = –3.2 mA
VCC – 0.7
V
IIL
Logical 0 input current, ports 1, 2, 3
VIN = 0.4 V
–1
ITL
Logical 1-to-0 transition current, ports 1, 2, 36
ILI
Input leakage current, port 0
ICC
Power supply current (see Figure 36):
Active mode (see Note 5)
Idle mode (see Note 5)
Power-down mode or clock stopped (see
Figure
40 for
Fi
f conditions)
diti
)
Tamb = 0°C to 70°C
Tamb = –40°C to +85°C
IPP
Programming current
11.5 V
RRST
Internal reset pull-down resistor
CIO
Pin
capacitance10
4.5 V < VCC < 5.5 V
LIMITS
–75
µA
VIN = 2.0 V
See Note 4
–650
µA
0.45 < VIN < VCC – 0.3
±10
µA
100
125
µA
µA
50
mA
225
kΩ
15
pF
See Note 5
VPP
20
12.5 V
40
(except EA)
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 VOLs of ALE and ports 1 and 3. The noise is due
to external bus capacitance discharging into the port 0 and port 2 pins when these pins make 1-to-0 transitions during bus operations. In 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. IOL can exceed these conditions provided that no
single output sinks more than 5 mA and no more than two outputs exceed the test conditions.
3. Capacitive loading on ports 0 and 2 may cause the VOH on ALE and PSEN to momentarily fall below the VCC–0.7 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 VIN is approximately 2 V.
5. See Figures 37 through 40 for ICC test conditions and Figure 36 for ICC vs Freq.
Active mode:
ICC(MAX) = (0.9 × FREQ. + 20)mA for all devices.
Idle mode:
ICC(MAX) = (0.37 × FREQ. +1.0)mA
6. This value applies to Tamb = 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, IOL must be externally limited as follows:
Maximum IOL per port pin:
15 mA (*NOTE: This is 85°C specification.)
26 mA
Maximum IOL per 8-bit port:
Maximum total IOL for all outputs:
71 mA
If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater than the listed
test conditions.
9. ALE is tested to VOH1, 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 less than 15 pF
(except EA is 25 pF).
1999 Oct 27
32
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
AC ELECTRICAL CHARACTERISTICS
Tamb = 0°C to +70°C or –40°C to +85°C, VCC = 5 V ±10%, VSS = 0 V1, 2, 3
VARIABLE CLOCK4
SYMBOL
FIGURE
1/tCLCL
29
PARAMETER
Oscillator frequency
Speed versions:
MIN
MAX
3.5
33
I;J;U (33 MHz)
33MHz CLOCK
MIN
MAX
3.5
33
UNIT
MHz
tLHLL
29
ALE pulse width
2tCLCL–40
21
ns
tAVLL
29
Address valid to ALE low
tCLCL–25
5
ns
tLLAX
29
Address hold after ALE low
tCLCL–25
5
tLLIV
29
ALE low to valid instruction in
tLLPL
29
ALE low to PSEN low
tCLCL–25
5
tPLPH
29
PSEN pulse width
3tCLCL–45
45
tPLIV
29
PSEN low to valid instruction in
tPXIX
29
Input instruction hold after PSEN
tPXIZ
29
Input instruction float after PSEN
tCLCL–25
5
ns
tAVIV
29
Address to valid instruction in
5tCLCL–80
70
ns
tPLAZ
29
PSEN low to address float
10
10
ns
4tCLCL–65
3tCLCL–60
0
ns
55
ns
ns
ns
30
0
ns
ns
Data Memory
tRLRH
30, 31
RD pulse width
6tCLCL–100
82
ns
tWLWH
30, 31
WR pulse width
6tCLCL–100
82
ns
tRLDV
30, 31
RD low to valid data in
tRHDX
30, 31
Data hold after RD
tRHDZ
30, 31
Data float after RD
2tCLCL–28
32
ns
tLLDV
30, 31
ALE low to valid data in
8tCLCL–150
90
ns
tAVDV
30, 31
Address to valid data in
105
ns
tLLWL
30, 31
ALE low to RD or WR low
3tCLCL–50
140
ns
tAVWL
30, 31
Address valid to WR low or RD low
4tCLCL–75
45
ns
tQVWX
30, 31
Data valid to WR transition
tCLCL–30
0
ns
tWHQX
30, 31
Data hold after WR
tCLCL–25
5
ns
tQVWH
31
7tCLCL–130
80
ns
tRLAZ
30, 31
RD low to address float
tWHLH
30, 31
RD or WR high to ALE high
5tCLCL–90
0
60
0
9tCLCL–165
Data valid to WR high
3tCLCL+50
40
0
tCLCL–25
tCLCL+25
5
ns
ns
0
ns
55
ns
External Clock
tCHCX
33
High time
17
tCLCL–tCLCX
ns
tCLCX
33
Low time
17
tCLCL–tCHCX
ns
tCLCH
33
Rise time
5
ns
tCHCL
33
Fall time
5
ns
tXLXL
32
Serial port clock cycle time
12tCLCL
360
ns
tQVXH
32
Output data setup to clock rising edge
10tCLCL–133
167
ns
tXHQX
32
Output data hold after clock rising edge
2tCLCL–80
50
ns
tXHDX
32
Input data hold after clock rising edge
0
0
ns
Shift Register
tXHDV
32
Clock rising edge to input data valid
10tCLCL–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.
1999 Oct 27
33
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
EXPLANATION OF THE AC SYMBOLS
P – PSEN
Q – Output data
R – RD signal
t – Time
V – Valid
W – WR signal
X – No longer a valid logic level
Z – Float
Examples: tAVLL = Time for address valid to ALE low.
tLLPL =Time for ALE low to PSEN low.
Each timing symbol has five characters. The first character is always
‘t’ (= time). The other characters, depending on their positions,
indicate the name of a signal or the logical status of that signal. The
designations are:
A – Address
C – Clock
D – Input data
H – Logic level high
I – Instruction (program memory contents)
L – Logic level low, or ALE
tLHLL
ALE
tAVLL
tLLPL
tPLPH
tLLIV
tPLIV
PSEN
tLLAX
INSTR IN
A0–A7
PORT 0
tPXIZ
tPLAZ
tPXIX
A0–A7
tAVIV
PORT 2
A0–A15
A8–A15
SU00006
Figure 29. External Program Memory Read Cycle
ALE
tWHLH
PSEN
tLLDV
tLLWL
tRLRH
RD
tAVLL
tLLAX
tRLAZ
PORT 0
tRHDZ
tRLDV
tRHDX
A0–A7
FROM RI OR DPL
DATA IN
A0–A7 FROM PCL
INSTR IN
tAVWL
tAVDV
PORT 2
P2.0–P2.7 OR A8–A15 FROM DPF
A0–A15 FROM PCH
SU00025
Figure 30. External Data Memory Read Cycle
1999 Oct 27
34
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
ALE
tWHLH
PSEN
tWLWH
tLLWL
WR
tLLAX
tAVLL
tWHQX
tQVWX
tQVWH
A0–A7
FROM RI OR DPL
PORT 0
DATA OUT
A0–A7 FROM PCL
INSTR IN
tAVWL
PORT 2
P2.0–P2.7 OR A8–A15 FROM DPF
A0–A15 FROM PCH
SU00026
Figure 31. External Data Memory Write Cycle
INSTRUCTION
0
1
2
3
4
5
6
7
8
ALE
tXLXL
CLOCK
tXHQX
tQVXH
OUTPUT DATA
0
1
2
WRITE TO SBUF
3
4
5
6
7
tXHDX
tXHDV
SET TI
INPUT DATA
VALID
VALID
VALID
VALID
VALID
VALID
VALID
VALID
CLEAR RI
SET RI
SU00027
Figure 32. Shift Register Mode Timing
VCC–0.5
0.45V
0.7VCC
0.2VCC–0.1
tCHCL
tCHCX
tCLCH
tCLCX
tCLCL
SU00009
Figure 33. External Clock Drive
1999 Oct 27
35
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
VCC–0.5
P89C51RC+/P89C51RD+
VLOAD+0.1V
0.2VCC+0.9
TIMING
REFERENCE
POINTS
VLOAD
0.2VCC–0.1
0.45V
VLOAD–0.1V
SU00717
SU00718
Figure 34. AC Testing Input/Output
Figure 35. Float Waveform
60
50
40
30
Icc ACTIVE MODE (TYP.)
20
10
Icc IDLE MODE (TYP.)
4
8
12
16
20
24
28
32
36
Frequency at XTAL1 (MHz)
SU01314
Figure 36. ICC vs. FREQ
Valid only within frequency specifications of the device under test
1999 Oct 27
VOL+0.1V
NOTE:
For timing purposes, a port is no longer floating when a 100mV change from
load voltage occurs, and begins to float when a 100mV change from the loaded
VOH/VOL level occurs. IOH/IOL ≥ ±20mA.
NOTE:
AC inputs during testing are driven at VCC –0.5 for a logic ‘1’ and 0.45V for a logic ‘0’.
Timing measurements are made at VIH min for a logic ‘1’ and VIL max for a logic ‘0’.
ICC (mA)
VOH–0.1V
36
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
VCC
VCC
ICC
ICC
VCC
VCC
VCC
VCC
RST
RST
P0
P0
EA
EA
(NC)
XTAL2
(NC)
XTAL2
CLOCK SIGNAL
XTAL1
CLOCK SIGNAL
XTAL1
VSS
VSS
SU00719
SU00720
Figure 37. ICC Test Condition, Active Mode
All other pins are disconnected
VCC–0.5
Figure 38. ICC Test Condition, Idle Mode
All other pins are disconnected
0.7VCC
0.2VCC–0.1
0.45V
tCHCL
tCHCX
tCLCH
tCLCX
tCLCL
SU00009
Figure 39. Clock Signal Waveform for ICC Tests in Active and Idle Modes
tCLCH = tCHCL = 5 ns
VCC
ICC
VCC
VCC
RST
P0
EA
(NC)
XTAL2
XTAL1
VSS
SU00016
Figure 40. ICC Test Condition, Power Down Mode
All other pins are disconnected. VCC = 2 V to 5.5 V
1999 Oct 27
VCC
37
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
FLASH EPROM MEMORY
CAPABILITIES OF THE PHILIPS 89C51
FLASH-BASED MICROCONTROLLERS
GENERAL DESCRIPTION
FLASH organization (89C51RC+ and 89C51RD+)
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 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.
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 VPP supply to perform the
Program/Erase algorithms.
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.
FEATURES
• 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
Boot ROM
without the need for a user provided loader.
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.
• 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.
1999 Oct 27
P89C51RC+/P89C51RD+
38
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
FFFF
FFFF
BOOT ROM
FC00
(1k BYTES ON
ALL PARTS)
BLOCK 4
16k BYTES
C000
BLOCK 3
16k BYTES
PROGRAM
ADDRESS
89C51RD+
8000
BLOCK 2
16k BYTES
4000
89C51RC+
BLOCK 1
8k BYTES
2000
BLOCK 0
8k BYTES
0000
SU01041
Figure 41. FLASH Memory Configurations
Power-On Reset Code Execution
Hardware Activation of the Boot Loader
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.
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.
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.
1999 Oct 27
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.
39
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
VCC
VPP
+12V
VCC
+5V
TxD
TxD
RxD
RxD
RST
XTAL2
VSS
XTAL1
VSS
SU01042
Figure 42. In-System Programming with a Minimum of Pins
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.
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.
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).
The ISP function uses five pins: TxD, RxD, VSS, 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 VPP supply should be adequately decoupled and provide a
minimum 50mA. VPP 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.
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.
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>
WinISP, a software utility to implement ISP programming with a PC,
is available from Philips.
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
1999 Oct 27
40
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
Table 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
1999 Oct 27
41
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
RECORD TYPE
04
P89C51RC+/P89C51RD+
COMMAND/DATA FUNCTION
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
= checksum
cc
Example:
:020000050001F8
1999 Oct 27
read signature byte – device id # 1
42
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
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.
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
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
1999 Oct 27
43
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
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
1999 Oct 27
P89C51RC+/P89C51RD+
44
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
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 BITS1
PROTECTION DESCRIPTION
LB1
LB2
LB3
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.
1999 Oct 27
45
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
DIP40: plastic dual in-line package; 40 leads (600 mil)
1999 Oct 27
46
P89C51RC+/P89C51RD+
SOT129-1
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
PLCC44: plastic leaded chip carrier; 44 leads
1999 Oct 27
P89C51RC+/P89C51RD+
SOT187-2
47
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
QFP44: plastic quad flat package; 44 leads
1999 Oct 27
48
P89C51RC+/P89C51RD+
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
NOTES
1999 Oct 27
49
P89C51RC+/P89C51RD+
Philips Semiconductors
Product specification
80C51 8-bit Flash microcontroller family
32K/64K ISP FLASH with 512–1K RAM
P89C51RC+/P89C51RD+
Data sheet status
Data sheet
status
Product
status
Definition [1]
Objective
specification
Development
This data sheet contains the design target or goal specifications for product development.
Specification may change in any manner without notice.
Preliminary
specification
Qualification
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.
Product
specification
Production
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.
[1] Please consult the most recently issued datasheet before initiating or completing a design.
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.
 Copyright Philips Electronics North America Corporation 1999
All rights reserved. Printed in U.S.A.
Philips Semiconductors
811 East Arques Avenue
P.O. Box 3409
Sunnyvale, California 94088–3409
Telephone 800-234-7381
Date of release: 10-99
Document order number:
1999 Oct 27
50
9397-750-06605