PHILIPS P87C51RA2FA

INTEGRATED CIRCUITS
P87C51RA2/RB2/RC2/RD2
80C51 8-bit microcontroller family
8KB/16KB/32KB/64KB OTP, 512B/512B/512B/1KB RAM,
low voltage (2.7 to 5.5 V), low power, high speed
(30/33 MHz)
Product data
Supersedes data of 2002 Oct 28
2003 Jan 24
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
• CMOS and TTL compatible
• Two speed ranges at VCC = 5 V
DESCRIPTION
The devices are Single-Chip 8-Bit Microcontrollers manufactured in
an advanced CMOS process and are derivatives of the 80C51
microcontroller family. The instruction set is 100% compatible with
the 80C51 instruction set.
– 0 to 30 MHz with 6-clock operation
– 0 to 33 MHz with 12-clock operation
• Parallel programming with 87C51 compatible hardware interface
The devices support 6-clock/12-clock mode selection by
programming an OTP bit (OX2) using parallel programming. In
addition, an SFR bit (X2) in the clock control register (CKCON)
also selects between 6-clock/12-clock mode.
to programmer
• RAM expandable externally to 64 kbytes
• Programmable Counter Array (PCA)
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.
– PWM
– Capture/compare
• PLCC, LQFP, or DIP package
• Extended temperature ranges
• Dual Data Pointers
• Security bits (3 bits)
• Encryption array - 64 bytes
• Seven interrupt sources
• 4 interrupt priority levels
• Four 8-bit I/O ports
• Full-duplex enhanced UART
The added features of the P87C51RA2/RB2/RC2/RD2 make it a
powerful microcontroller for applications that require pulse width
modulation, high-speed I/O and up/down counting capabilities such
as motor control.
FEATURES
• 80C51 Central Processing Unit
– 8 kbytes OTP (87C51RA2)
– 16 kbytes OTP (87C51RB2)
– 32 kbytes OTP (87C51RC2)
– 64 kbytes OTP (87C51RD2)
– 512 byte RAM (87C51RA2/RB2/RC2)
– 1 kbyte RAM (87C51RD2)
– Framing error detection
– Boolean processor
– Automatic address recognition
• Three 16-bit timers/counters T0, T1 (standard 80C51) and
– Fully static operation
additional T2 (capture and compare)
– Low voltage (2.7 V to 5.5 V at 16 MHz) operation
• Programmable clock-out pin
• Asynchronous port reset
• Low EMI (inhibit ALE, slew rate controlled outputs, and 6-clock
• 12-clock operation with selectable 6-clock operation (via software
or via parallel programmer)
• Memory addressing capability
– Up to 64 kbytes ROM and 64 kbytes RAM
mode)
• Power control modes:
• Wake-up from Power Down by an external interrupt
– Clock can be stopped and resumed
– Idle mode
– Power-down mode
2003 Jan 24
2
853–2391 29335
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
SELECTION TABLE
Serial
Interfaces
PWM
PCA
WD
UART
I 2C
CAN
SPI
ADC bits/ch.
I/O Pins
Interrupts
(Ext.)/Levels
Default Clock
Rate
Optional
Clock Rate
Reset active
low/high?
P87C51RD2
1K
–
64K
–
4
√
√
√
√
–
–
–
–
32
7(2)/4
√
12-clk
6-clk
H
30/33
0-16
0-30/33
P87C51RC2
512B
–
32K
–
4
√
√
√
√
–
–
–
–
32
7(2)/4
√
12-clk
6-clk
H
30/33
0-16
0-30/33
P87C51RB2
512B
–
16K
–
4
√
√
√
√
–
–
–
–
32
7(2)/4
√
12-clk
6-clk
H
30/33
0-16
0-30/33
P87C51RA2
512B
–
8K
–
4
√
√
√
√
–
–
–
–
32
7(2)/4
√
12-clk
6-clk
H
30/33
0-16
0-30/33
Program
Security
# of Timers
Max.
Freq.
at 6-clk
/ 12-clk
(MHz)
RAM
Flash
Timers
OTP
Memory
ROM
Type
Freq.
Range
at 3V
(MHz)
Freq.
Range
at
5V
(MHz)
ORDERING INFORMATION
PHILIPS
((EXCEPT NORTH AMERICA))
PART ORDER NUMBER
PART MARKING
MEMORY
TEMPERATURE RANGE
(°C)
AND PACKAGE
VOLTAGE RANGE
DWG #
OTP
RAM
P87C51RA2BA
8 KB
512B
0 to +70, PLCC
2.7 to 5.5 V
SOT187-2
P87C51RA2FA
8 KB
512B
–40 to +85, PLCC
2.7 to 5.5 V
SOT187-2
P87C51RA2BBD
8 KB
512B
0 to +70, LQFP
2.7 to 5.5 V
SOT389-1
P87C51RB2BA
16 KB
512B
0 to +70, PLCC
2.7 to 5.5 V
SOT187-2
P87C51RB2FA
16 KB
512B
–40 to +85, PLCC
2.7 to 5.5 V
SOT187-2
P87C51RB2BBD
16 KB
512B
0 to +70, LQFP
2.7 to 5.5 V
SOT389-1
P87C51RB2BN
16 KB
512B
0 to +70, DIP40
2.7 to 5.5 V
SOT129-1
P87C51RB2FN
16 KB
512B
–40 to +85, DIP40
2.7 to 5.5 V
SOT129-1
P87C51RC2BA
32 KB
512B
0 to +70, PLCC
2.7 to 5.5 V
SOT187-2
P87C51RC2FA
32 KB
512B
–40 to +85, PLCC
2.7 to 5.5 V
SOT187-2
P87C51RC2BBD
32 KB
512B
0 to +70, LQFP
2.7 to 5.5 V
SOT389-1
P87C51RC2BN
32 KB
512B
0 to +70, DIP40
2.7 to 5.5 V
SOT129-1
P87C51RC2FN
32 KB
512B
–40 to +85, DIP40
2.7 to 5.5 V
SOT129-1
P87C51RD2BA
64 KB
1 KB
0 to +70, PLCC
2.7 to 5.5 V
SOT187-2
P87C51RD2FA
64 KB
1 KB
–40 to +85, PLCC
2.7 to 5.5 V
SOT187-2
P87C51RD2BBD
64 KB
1 KB
0 to +70, LQFP
2.7 to 5.5 V
SOT389-1
P87C51RD2FBD
64 KB
1 KB
–40 to +85, LQFP
2.7 to 5.5 V
SOT389-1
P87C51RD2BN
64 KB
1 KB
0 to +70, DIP40
2.7 to 5.5 V
SOT129-1
2003 Jan 24
3
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
BLOCK DIAGRAM 1
ACCELERATED 80C51 CPU
(12-CLK MODE, 6-CLK MODE)
8K / 16K / 32K /
64 KBYTE
CODE OTP
FULL-DUPLEX
ENHANCED UART
512 / 1024 BYTE
DATA RAM
TIMER 0
TIMER 1
PORT 3
CONFIGURABLE I/Os
TIMER 2
PORT 2
CONFIGURABLE I/Os
PROGRAMMABLE
COUNTER ARRAY
(PCA)
PORT 1
CONFIGURABLE I/Os
WATCHDOG TIMER
PORT 0
CONFIGURABLE I/Os
CRYSTAL OR
RESONATOR
OSCILLATOR
su01657
2003 Jan 24
4
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
BLOCK DIAGRAM (CPU-ORIENTED)
P0.0–P0.7
P2.0–P2.7
PORT 0
DRIVERS
PORT 2
DRIVERS
VCC
VSS
RAM ADDR
REGISTER
PORT 0
LATCH
RAM
OTP
MEMORY
PORT 2
LATCH
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
SU01658
2003 Jan 24
5
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
LOGIC SYMBOL
Plastic Leaded Chip Carrier
VCC
6
VSS
XTAL1
PORT 0
DATA BUS
LCC
17
PORT 1
RST
EA/VPP
PSEN
29
18
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
PORT 2
ALE/PROG
PORT 3
39
ADDRESS AND
T2
T2EX
SECONDARY FUNCTIONS
40
7
XTAL2
RxD
TxD
INT0
INT1
T0
T1
WR
RD
1
ADDRESS BUS
SU01672
PINNING
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
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
Pin
31
32
33
34
35
36
37
38
39
40
41
42
43
44
* NO INTERNAL CONNECTION
Function
P2.7/A15
PSEN
ALE/PROG
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
SU00023
Plastic Dual In-Line Package
Plastic Quad Flat Pack
T2/P1.0 1
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
RST 9
32 P0.7/AD7
RxD/P3.0 10
TxD/P3.1 11
DUAL
IN-LINE
PACKAGE
44
1
11
29 PSEN
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
* NO INTERNAL CONNECTION
SU00021
2003 Jan 24
23
12
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
30 ALE/PROG
INT1/P3.3 13
33
LQFP
31 EA/VPP
INT0/P3.2 12
34
6
Pin
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
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/PROG
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
SU01400
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
PIN DESCRIPTIONS
PIN NUMBER
MNEMONIC
TYPE
NAME AND FUNCTION
PDIP
PLCC
LQFP
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 on all pins.
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
40
I/O
2
3
4
5
6
7
8
3
4
5
6
7
8
9
41
42
43
44
1
2
3
I
I
I/O
I/O
I/O
I/O
I/O
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 P87C51RA2/RB2/RC2/RD2, 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 twice
every machine cycle, 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
2003 Jan 24
Alternate functions for P87C51RA2/RB2/RC2/RD2 Port 1 include:
T2 (P1.0): Timer/Counter 2 external count input/Clockout (see Programmable
Clock-Out)
T2EX (P1.1): Timer/Counter 2 Reload/Capture/Direction Control
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
7
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
PIN NUMBER
MNEMONIC
TYPE
P87C51RA2/RB2/RC2/RD2
NAME AND FUNCTION
PDIP
PLCC
LQFP
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. If EA is held high, the device executes from internal program memory.
The value on the EA pin is latched when RST is released and any subsequent
changes have no effect. This pin also receives the programming supply voltage
(VPP) during 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) must not be higher than VCC + 0.5 V or less than VSS – 0.5 V.
2003 Jan 24
8
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
SPECIAL FUNCTION REGISTERS
SYMBOL
DESCRIPTION
DIRECT
ADDRESS
BIT ADDRESS, SYMBOL, OR ALTERNATIVE PORT FUNCTION
MSB
LSB
RESET
VALUE
ACC*
Accumulator
E0H
E7
E6
E5
E4
E3
E2
E1
E0
00H
AUXR#
Auxiliary
8EH
–
–
–
–
–
–
EXTRAM
AO
xxxxxx00B
AUXR1#
Auxiliary 1
A2H
–
–
–
–
GF2
0
–
DPS
xxxxxxx0B
B*
B register
F0H
F7
F6
F5
F4
F3
F2
F1
F0
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
CCON*#
CH#
PCA Counter Control
PCA Counter High
D8H
F9H
CF
CR
–
CCF4
CCF3
CCF2
CCF1
CCF0
CKCON#
CL#
Clock control
PCA Counter Low
8FH
E9H
–
–
–
–
–
–
–
X2
CMOD#
PCA Counter Mode
D9H
CIDL
WDTE
–
–
–
CPS1
CPS0
ECF
DPTR:
DPH
DPL
Data Pointer (2 bytes)
Data Pointer High
Data Pointer Low
83H
82H
IE*
Interrupt Enable 0
A8H
00H
xxxxxxxxB
xxxxxxxxB
xxxxxxxxB
xxxxxxxxB
xxxxxxxxB
xxxxxxxxB
xxxxxxxxB
xxxxxxxxB
xxxxxxxxB
xxxxxxxxB
00x00000B
00H
x0000000B
00H
00xxx000B
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
00H
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
P2*
Port 2
A0H
AD15
AD14
AD13
AD12
AD11
AD10
AD9
AD8
B7
B6
B5
B4
B3
B2
B1
B0
RD
WR
T1
T0
INT1
INT0
TxD
RxD
FFH
SMOD0
–
POF
GF1
GF0
PD
IDL
00xxx000B
P3*
Port 3
B0H
PCON#1
Power Control
87H
SMOD1
* SFRs are bit addressable.
# SFRs are modified from or added to the 80C51 SFRs.
– Reserved bits.
1. Reset value depends on reset source.
2003 Jan 24
9
x0000000B
x0000000B
FFH
FFH
FFH
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
SPECIAL FUNCTION REGISTERS (Continued)
BIT ADDRESS, SYMBOL, OR ALTERNATIVE PORT FUNCTION
DESCRIPTION
DIRECT
ADDRESS
PSW*
Program Status Word
D0H
RCAP2H#
RCAP2L#
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
MSB
LSB
D7
D6
D5
D4
D3
D2
D1
D0
CY
AC
F0
RS1
RS0
OV
F1
P
00000000B
xxxxxxxxB
9F
9E
9D
9C
9B
9A
99
98
SM1
SM2
REN
TB8
RB8
TI
RI
SCON*
SP
Serial Control
Stack Pointer
98H
81H
SM0/FE
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
GATE
WDTRST Watchdog Timer Reset
A6H
* SFRs are bit addressable.
# SFRs are modified from or added to the 80C51 SFRs.
– Reserved bits.
00H
07H
00H
00H
xxxxxx00B
00H
00H
00H
00H
00H
00H
C/T
M1
M0
GATE
C/T
M1
M0
00H
This device is configured at the factory to operate using 12 clock
periods per machine cycle, referred to in this datasheet as “12-clock
mode”. It may be optionally configured on commercially available
parallel programming equipment or via software to operate at
6 clocks per machine cycle, referred to in this datasheet as “6-clock
mode”. (This yields performance equivalent to twice that of standard
80C51 family devices). Also see next page.
OSCILLATOR CHARACTERISTICS
XTAL1 and XTAL2 are the input and output, respectively, of an
inverting amplifier. The pins can be configured for use as an
on-chip oscillator.
To drive the device from an external clock source, XTAL1 should be
driven while XTAL2 is left unconnected. Minimum and maximum
high and low times specified in the data sheet must be observed.
2003 Jan 24
RESET
VALUE
10
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
OX2, when programmed (6-clock mode), supersedes the X2 bit
(CKCON.0). The CKCON register is shown below in Figure 1.
CLOCK CONTROL REGISTER (CKCON)
This device allows control of the 6-clock/12-clock mode by means of
both an SFR bit (X2) and an OTP bit. The OTP clock control bit
CKCON
Address = 8Fh
Reset Value = x0000000B
Not Bit Addressable
7
–
BIT
CKCON.7
CKCON.6
CKCON.5
CKCON.4
CKCON.3
CKCON.2
CKCON.1
CKCON.0
SYMBOL
–
X2
6
5
4
3
2
1
0
–
–
–
–
–
–
X2
FUNCTION
Reserved.
Reserved.
Reserved.
Reserved.
Reserved.
Reserved.
Reserved.
CPU clock; 1 = 6 clocks for each machine cycle, 0 = 12 clocks for each machine cycle
SU01689
Figure 1. Clock control (CKCON) register
Also please note that the clock divider applies to the serial port for
modes 0 & 2 (fixed baud rate modes). This is because modes 1 & 3
(variable baud rate modes) use either Timer 1 or Timer 2.
RESET
A reset is accomplished by holding the RST pin high for at least two
machine cycles (12 oscillator periods in 6-clock mode, or 24 oscillator
periods in 12-clock mode), while the oscillator is running. To ensure 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 RST.
Below is the truth table for the CPU clock mode.
Table 1.
OX2 clock mode bit
(can only be set by
parallel programmer)
X2 bit
(CKCON.0)
CPU clock mode
erased
0
12-clock mode
(default)
erased
1
6-clock mode
programmed
X
6-clock mode
2003 Jan 24
The value on the EA pin is latched when RST is deasserted and has
no further effect.
11
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
LOW POWER MODES
Stop Clock Mode
Design Consideration
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.
When the idle mode is terminated by a hardware reset, the device
normally resumes program execution, from where it left off, up to
two machine cycles before the internal reset algorithm takes control.
On-chip hardware inhibits access to internal RAM in this event, but
access to the port pins is not inhibited. To eliminate the possibility of
an unexpected write when Idle is terminated by reset, the instruction
following the one that invokes Idle should not be one that writes to a
port pin or to external memory.
Idle Mode
In the idle mode (see Table 2), the CPU puts itself to sleep while all
of the on-chip peripherals stay active. The instruction to invoke the
idle mode is the last instruction executed in the normal operating
mode before the idle mode is activated. The CPU contents, the
on-chip RAM, and all of the special function registers remain intact
during this mode. The idle mode can be terminated either by any
enabled interrupt (at which time the process is picked up at the
interrupt service routine and continued), or by a hardware reset
which starts the processor in the same manner as a power-on reset.
ONCE Mode
The ONCE (“On-Circuit Emulation”) Mode facilitates testing and
debugging of systems without the device having to be removed from
the circuit. The ONCE Mode is invoked by:
1. Pull ALE low while the device is in reset and PSEN is high;
2. Hold ALE low as RST is deactivated.
While the device is in ONCE Mode, the Port 0 pins go into a float
state, and the other port pins and ALE and PSEN are weakly pulled
high. The oscillator circuit remains active. While the device is in this
mode, an emulator or test CPU can be used to drive the circuit.
Normal operation is restored when a normal reset is applied.
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 V 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
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.
2. to output a 50% duty cycle clock ranging from 61 Hz to 4 MHz at a
16 MHz operating frequency in 12-clock mode (122 Hz to 8 MHz in
6-clock mode).
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 10 ms).
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.
n
Oscillator Frequency
(65536 * RCAP2H, RCAP2L)
n=
2 in 6-clock mode
4 in 12-clock mode
POWER-ON FLAG
The Power-On Flag (POF) is set by on-chip circuitry when the VCC
level on the P87C51RA2/RB2/RC2/RD2 rises from 0 to 5 V. 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 3 V for the POF
to remain unaffected by the VCC level.
Where (RCAP2H,RCAP2L) = the content of RCAP2H and RCAP2L
taken as a 16-bit unsigned integer.
In the Clock-Out mode Timer 2 roll-overs will not generate an
interrupt. This is similar to when it is used as a baud-rate generator.
It is possible to use Timer 2 as a baud-rate generator and a clock
generator simultaneously. Note, however, that the baud-rate and the
Clock-Out frequency will be the same.
Table 2. External Pin Status During Idle and Power-Down Mode
MODE
PROGRAM MEMORY
ALE
PSEN
Idle
Internal
1
Idle
External
1
Power-down
Internal
Power-down
External
2003 Jan 24
PORT 0
PORT 1
1
Data
1
Float
0
0
0
0
12
PORT 2
PORT 3
Data
Data
Data
Data
Address
Data
Data
Data
Data
Data
Float
Data
Data
Data
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
Timer 0 and Timer 1
Mode 1
Mode 1 is the same as Mode 0, except that the Timer register is
being run with all 16 bits.
The “Timer” or “Counter” function is selected by control bits C/T in
the Special Function Register TMOD. These two Timer/Counters
have four operating modes, which are selected by bit-pairs (M1, M0)
in TMOD. Modes 0, 1, and 2 are the same for both Timers/Counters.
Mode 3 is different. The four operating modes are described in the
following text.
Mode 2
Mode 2 configures the Timer register as an 8-bit Counter (TLn) with
automatic reload, as shown in Figure 5. Overflow from TLn not only
sets TFn, but also reloads TLn with the contents of THn, which is
preset by software. The reload leaves THn unchanged.
TIMER 0 AND TIMER 1 OPERATION
Mode 2 operation is the same for Timer 0 as for Timer 1.
Mode 0
Putting either Timer into Mode 0 makes it look like an 8048 Timer,
which is an 8-bit Counter with a divide-by-32 prescaler. Figure 3
shows the Mode 0 operation.
Mode 3
Timer 1 in Mode 3 simply holds its count. The effect is the same as
setting TR1 = 0.
In this mode, the Timer register is configured as a 13-bit register. As
the count rolls over from all 1s to all 0s, it sets the Timer interrupt
flag TFn. The counted input is enabled to the Timer when TRn = 1
and either GATE = 0 or INTn = 1. (Setting GATE = 1 allows the
Timer to be controlled by external input INTn, to facilitate pulse width
measurements). TRn is a control bit in the Special Function Register
TCON (Figure 4).
Timer 0 in Mode 3 establishes TL0 and TH0 as two separate
counters. The logic for Mode 3 on Timer 0 is shown in Figure 6. TL0
uses the Timer 0 control bits: C/T, GATE, TR0, and TF0 as well as
pin INT0. TH0 is locked into a timer function (counting machine
cycles) and takes over the use of TR1 and TF1 from Timer 1. Thus,
TH0 now controls the “Timer 1” interrupt.
Mode 3 is provided for applications requiring an extra 8-bit timer on
the counter. With Timer 0 in Mode 3, an 80C51 can look like it has
three Timer/Counters. When Timer 0 is in Mode 3, Timer 1 can be
turned on and off by switching it out of and into its own Mode 3, or
can still be used by the serial port as a baud rate generator, or in
fact, in any application not requiring an interrupt.
The 13-bit register consists of all 8 bits of THn and the lower 5 bits
of TLn. The upper 3 bits of TLn are indeterminate and should be
ignored. Setting the run flag (TRn) does not clear the registers.
Mode 0 operation is the same for Timer 0 as for Timer 1. There are
two different GATE bits, one for Timer 1 (TMOD.7) and one for Timer
0 (TMOD.3).
TMOD
Address = 89H
Reset Value = 00H
Not Bit Addressable
7
6
5
4
3
2
1
0
GATE
C/T
M1
M0
GATE
C/T
M1
M0
TIMER 1
BIT
TMOD.3/
TMOD.7
TMOD.2/
TMOD.6
SYMBOL
GATE
C/T
TIMER 0
FUNCTION
Gating control when set. Timer/Counter “n” is enabled only while “INTn” pin is high and
“TRn” control pin is set. when cleared Timer “n” is enabled whenever “TRn” control bit is set.
Timer or Counter Selector cleared for Timer operation (input from internal system clock.)
Set for Counter operation (input from “Tn” input pin).
M1
M0
OPERATING
0
0
8048 Timer: “TLn” serves as 5-bit prescaler.
0
1
16-bit Timer/Counter: “THn” and “TLn” are cascaded; there is no prescaler.
1
0
8-bit auto-reload Timer/Counter: “THn” holds a value which is to be reloaded
into “TLn” each time it overflows.
1
1
(Timer 0) TL0 is an 8-bit Timer/Counter controlled by the standard Timer 0 control bits.
TH0 is an 8-bit timer only controlled by Timer 1 control bits.
1
1
(Timer 1) Timer/Counter 1 stopped.
SU01580
Figure 2. Timer/Counter 0/1 Mode Control (TMOD) Register
2003 Jan 24
13
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
÷ d*
OSC
C/T = 0
TLn
(5 Bits)
THn
(8 Bits)
TFn
Interrupt
C/T = 1
Control
Tn Pin
TRn
Timer n
Gate bit
INTn Pin
*d = 6 in 6-clock mode; d = 12 in 12-clock mode.
SU01618
Figure 3. Timer/Counter 0/1 Mode 0: 13-Bit Timer/Counter
TCON
Address = 88H
Reset Value = 00H
Bit Addressable
7
TF1
BIT
TCON.7
SYMBOL
TF1
TCON.6
TCON.5
TR1
TF0
TCON.4
TCON.3
TR0
IE1
TCON.2
IT1
TCON.1
IE0
TCON.0
IT0
6
5
4
3
2
1
0
TR1
TF0
TR0
IE1
IT1
IE0
IT0
FUNCTION
Timer 1 overflow flag. Set by hardware on Timer/Counter overflow.
Cleared by hardware when processor vectors to interrupt routine, or clearing the bit in software.
Timer 1 Run control bit. Set/cleared by software to turn Timer/Counter on/off.
Timer 0 overflow flag. Set by hardware on Timer/Counter overflow.
Cleared by hardware when processor vectors to interrupt routine, or by clearing the bit in software.
Timer 0 Run control bit. Set/cleared by software to turn Timer/Counter on/off.
Interrupt 1 Edge flag. Set by hardware when external interrupt edge detected.
Cleared when interrupt processed.
Interrupt 1 type control bit. Set/cleared by software to specify falling edge/low level triggered
external interrupts.
Interrupt 0 Edge flag. Set by hardware when external interrupt edge detected.
Cleared when interrupt processed.
Interrupt 0 Type control bit. Set/cleared by software to specify falling edge/low level
triggered external interrupts.
SU01516
Figure 4. Timer/Counter 0/1 Control (TCON) Register
2003 Jan 24
14
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
÷ d*
OSC
C/T = 0
TLn
(8 Bits)
TFn
Interrupt
C/T = 1
Control
Tn Pin
Reload
TRn
Timer n
Gate bit
THn
(8 Bits)
INTn Pin
SU01619
*d = 6 in 6-clock mode; d = 12 in 12-clock mode.
Figure 5. Timer/Counter 0/1 Mode 2: 8-Bit Auto-Reload
÷ d*
OSC
C/T = 0
TL0
(8 Bits)
TF0
Interrupt
TH0
(8 Bits)
TF1
Interrupt
C/T = 1
Control
T0 Pin
TR0
Timer 0
Gate bit
INT0 Pin
OSC
÷ d*
Control
TR1
*d = 6 in 6-clock mode; d = 12 in 12-clock mode.
SU01620
Figure 6. Timer/Counter 0 Mode 3: Two 8-Bit Counters
2003 Jan 24
15
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
Counter Enable) which is located in the T2MOD register (see
Figure 3). When reset is applied the DCEN=0 which means Timer 2
will default to counting up. If DCEN bit is set, Timer 2 can count up
or down depending on the value of the T2EX pin.
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/6 pulses
(osc/12 in 12-clock mode).).
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
(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/6 in 6-clock mode or OSC/12 in 12-clock mode)
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.
SU01251
Figure 1. Timer/Counter 2 (T2CON) Control Register
2003 Jan 24
16
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
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
÷ n*
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
SU01252
* n = 6 in 6-clock mode, or 12 in 12-clock mode.
Figure 2. Timer 2 in Capture Mode
T2MOD
Address = 0C9H
Reset Value = XXXX XX00B
Not Bit Addressable
Bit
*
—
—
—
—
—
—
T2OE
DCEN
7
6
5
4
3
2
1
0
Symbol
Function
—
Not implemented, reserved for future use.*
T2OE
Timer 2 Output Enable bit.
DCEN
Down Count Enable bit. When set, this allows Timer 2 to be configured as an up/down counter.
User software should not write 1s to reserved bits. These bits may be used in future 8051 family products to invoke new features.
In that case, the reset or inactive value of the new bit will be 0, and its active value will be 1. The value read from a reserved bit is
indeterminate.
SU00729
Figure 3. Timer 2 Mode (T2MOD) Control Register
2003 Jan 24
17
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
÷ n*
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
SU01253
EXEN2
* n = 6 in 6-clock mode, or 12 in 12-clock mode.
Figure 4. Timer 2 in Auto-Reload Mode (DCEN = 0)
(DOWN COUNTING RELOAD VALUE)
FFH
FFH
TOGGLE
EXF2
OSC
÷ n*
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)
* n = 6 in 6-clock mode, or 12 in 12-clock mode.
SU01254
Figure 5. Timer 2 Auto Reload Mode (DCEN = 1)
2003 Jan 24
T2EX PIN
18
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
Timer 1
Overflow
n = 1 in 6-clock mode
n = 2 in 12-clock mode
÷2
“0”
÷n
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
RX Clock
“0”
TCLK
RCAP2H
÷ 16
TX Clock
Timer 2
Interrupt
Control
EXEN2
Note availability of additional external interrupt.
SU01629
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
Baud Rate
Modes 1 and 3 Baud Rates + Timer 2 Overflow Rate
16
The timer can be configured for either “timer” or “counter” operation.
In many applications, it is configured for “timer” operation (C/T2=0).
Timer operation is different for Timer 2 when it is being used as a
baud rate generator.
Timer 2
12-clock
mode
6-clock
mode
Osc Freq
375 k
9.6 k
4.8 k
2.4 k
1.2 k
300
110
300
110
750 k
19.2 k
9.6 k
4.8 k
2.4 k
600
220
600
220
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
Usually, as a timer it would increment every machine cycle (i.e.,
the oscillator frequency in 6-clock mode, 1/12 the oscillator
frequency in 12-clock mode). As a baud rate generator, it
increments at the oscillator frequency in 6-clock mode (OSC/2 in
12-clock mode). Thus the baud rate formula is as follows:
1/
6
Modes 1 and 3 Baud Rates =
Oscillator Frequency
[ n * [65536 * (RCAP2H, RCAP2L)]]
Baud Rate Generator Mode
*n=
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.
Where: (RCAP2H, RCAP2L)= The content of RCAP2H and
RCAP2L taken as a 16-bit unsigned integer.
The Timer 2 as a baud rate generator mode shown in Figure 6, is
valid only if RCLK and/or TCLK = 1 in T2CON register. Note that a
rollover in TH2 does not set TF2, and will not generate an interrupt.
Thus, the Timer 2 interrupt does not have to be disabled when
Timer 2 is in the baud rate generator mode. Also if the EXEN2
(T2 external enable flag) is set, a 1-to-0 transition in T2EX
(Timer/counter 2 trigger input) will set EXF2 (T2 external flag) but
will not cause a reload from (RCAP2H, RCAP2L) to (TH2,TL2).
Therefore when Timer 2 is in use as a baud rate generator, T2EX
can be used as an additional external interrupt, if needed.
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.
2003 Jan 24
16 in 6-clock mode
32 in 12-clock mode
19
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
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 +
*n=
f OSC
[65536 * (RCAP2H, RCAP2L)]]
16 in 6-clock mode
32 in 12-clock mode
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 *
Summary of Baud Rate Equations
Timer 2 is in baud rate generating mode. If Timer 2 is being clocked
through pin T2 (P1.0) the baud rate is:
ǒ
n*
f OSC
Baud Rate
Ǔ
Timer/Counter 2 Set-up
Baud Rate + Timer 2 Overflow Rate
16
Table 5.
[ n*
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.
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.
2003 Jan 24
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Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
The slaves that weren’t being addressed leave their SM2s set and
go on about their business, ignoring the coming data bytes.
FULL-DUPLEX ENHANCED UART
Standard UART operation
SM2 has no effect in Mode 0, and in Mode 1 can be used to check
the validity of the stop bit. In a Mode 1 reception, if SM2 = 1, the
receive interrupt will not be activated unless a valid stop bit is
received.
The serial port is full duplex, meaning it can transmit and receive
simultaneously. It is also receive-buffered, meaning it can
commence reception of a second byte before a previously received
byte has been read from the register. (However, if the first byte still
hasn’t been read by the time reception of the second byte is
complete, one of the bytes will be lost.) The serial port receive and
transmit registers are both accessed at Special Function Register
SBUF. Writing to SBUF loads the transmit register, and reading
SBUF accesses a physically separate receive register.
Serial Port Control Register
The serial port control and status register is the Special Function
Register SCON, shown in Figure 7. This register contains not only
the mode selection bits, but also the 9th data bit for transmit and
receive (TB8 and RB8), and the serial port interrupt bits (TI and RI).
The serial port can operate in 4 modes:
Mode 0:
Serial data enters and exits through RxD. TxD outputs
the shift clock. 8 bits are transmitted/received (LSB first).
The baud rate is fixed at 1/12 the oscillator frequency in
12-clock mode or 1/6 the oscillator frequency in 6-clock
mode.
Mode 1:
10 bits are transmitted (through TxD) or received
(through RxD): a start bit (0), 8 data bits (LSB first), and
a stop bit (1). On receive, the stop bit goes into RB8 in
Special Function Register SCON. The baud rate is
variable.
Mode 2:
Mode 3:
Baud Rates
The baud rate in Mode 0 is fixed: Mode 0 Baud Rate = Oscillator
Frequency / 12 (12-clock mode) or / 6 (6-clock mode). The baud
rate in Mode 2 depends on the value of bit SMOD in Special
Function Register PCON. If SMOD = 0 (which is the value on reset),
and the port pins in 12-clock mode, the baud rate is 1/64 the
oscillator frequency. If SMOD = 1, the baud rate is 1/32 the oscillator
frequency. In 6-clock mode, the baud rate is 1/32 or 1/16 the
oscillator frequency, respectively.
Mode 2 Baud Rate =
2 SMOD
n
11 bits are transmitted (through TxD) or received
(through RxD): start bit (0), 8 data bits (LSB first), a
programmable 9th data bit, and a stop bit (1). On
Transmit, the 9th data bit (TB8 in SCON) can be
assigned the value of 0 or 1. Or, for example, the parity
bit (P, in the PSW) could be moved into TB8. On receive,
the 9th data bit goes into RB8 in Special Function
Register SCON, while the stop bit is ignored. The baud
rate is programmable to either 1/32 or 1/64 the oscillator
frequency in 12-clock mode or 1/16 or 1/32 the oscillator
frequency in 6-clock mode.
Where:
n = 64 in 12-clock mode, 32 in 6-clock mode
The baud rates in Modes 1 and 3 are determined by the Timer 1 or
Timer 2 overflow rate.
Using Timer 1 to Generate Baud Rates
When Timer 1 is used as the baud rate generator (T2CON.RCLK
= 0, T2CON.TCLK = 0), the baud rates in Modes 1 and 3 are
determined by the Timer 1 overflow rate and the value of SMOD as
follows:
11 bits are transmitted (through TxD) or received
(through RxD): a start bit (0), 8 data bits (LSB first), a
programmable 9th data bit, and a stop bit (1). In fact,
Mode 3 is the same as Mode 2 in all respects except
baud rate. The baud rate in Mode 3 is variable.
Mode 1, 3 Baud Rate =
2 SMOD
n
(Timer 1 Overflow Rate)
Where:
In all four modes, transmission is initiated by any instruction that
uses SBUF as a destination register. Reception is initiated in Mode 0
by the condition RI = 0 and REN = 1. Reception is initiated in the
other modes by the incoming start bit if REN = 1.
n = 32 in 12-clock mode, 16 in 6-clock mode
The Timer 1 interrupt should be disabled in this application. The
Timer itself can be configured for either “timer” or “counter”
operation, and in any of its 3 running modes. In the most typical
applications, it is configured for “timer” operation, in the auto-reload
mode (high nibble of TMOD = 0010B). In that case the baud rate is
given by the formula:
Multiprocessor Communications
Modes 2 and 3 have a special provision for multiprocessor
communications. In these modes, 9 data bits are received. The 9th
one goes into RB8. Then comes a stop bit. The port can be
programmed such that when the stop bit is received, the serial port
interrupt will be activated only if RB8 = 1. This feature is enabled by
setting bit SM2 in SCON. A way to use this feature in multiprocessor
systems is as follows:
Mode 1, 3 Baud Rate =
2 SMOD
n
Oscillator Frequency
12 [256–(TH1)]
Where:
When the master processor wants to transmit a block of data to one
of several slaves, it first sends out an address byte which identifies
the target slave. An address byte differs from a data byte in that the
9th bit is 1 in an address byte and 0 in a data byte. With SM2 = 1, no
slave will be interrupted by a data byte. An address byte, however,
will interrupt all slaves, so that each slave can examine the received
byte and see if it is being addressed. The addressed slave will clear
its SM2 bit and prepare to receive the data bytes that will be coming.
2003 Jan 24
(Oscillator Frequency)
n = 32 in 12-clock mode, 16 in 6-clock mode
One can achieve very low baud rates with Timer 1 by leaving the
Timer 1 interrupt enabled, and configuring the Timer to run as a
16-bit timer (high nibble of TMOD = 0001B), and using the Timer 1
interrupt to do a 16-bit software reload. Figure 8 lists various
commonly used baud rates and how they can be obtained from
Timer 1.
21
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
SCON
Address = 98H
Bit Addressable
Reset Value = 00H
7
6
5
4
3
2
1
0
SM0
SM1
SM2
REN
TB8
RB8
TI
RI
Where SM0, SM1 specify the serial port mode, as follows:
SM0
0
0
1
1
SM1
0
1
0
1
Mode
0
1
2
3
Description
shift register
8-bit UART
9-bit UART
9-bit UART
Baud Rate
fOSC/12 (12-clock mode) or fOSC/6 (6-clock mode)
variable
fOSC/64 or fOSC/32 (12-clock mode) or fOSC/32 or fOSC/16 (6-clock mode)
variable
SM2
Enables the multiprocessor communication feature in Modes 2 and 3. In Mode 2 or 3, if SM2 is set to 1, then Rl will not be
activated if the received 9th data bit (RB8) is 0. In Mode 1, if SM2=1 then RI will not be activated if a valid stop bit was not
received. In Mode 0, SM2 should be 0.
REN
Enables serial reception. Set by software to enable reception. Clear by software to disable reception.
TB8
The 9th data bit that will be transmitted in Modes 2 and 3. Set or clear by software as desired.
RB8
In Modes 2 and 3, is the 9th data bit that was received. In Mode 1, it SM2=0, RB8 is the stop bit that was received. In Mode 0,
RB8 is not used.
TI
Transmit interrupt flag. Set by hardware at the end of the 8th bit time in Mode 0, or at the beginning of the stop bit in the other
modes, in any serial transmission. Must be cleared by software.
RI
Receive interrupt flag. Set by hardware at the end of the 8th bit time in Mode 0, or halfway through the stop bit time in the other
modes, in any serial reception (except see SM2). Must be cleared by software.
SU01626
Figure 7. Serial Port Control (SCON) Register
Timer 1
Baud Rate
Mode
12-clock mode
6-clock mode
Mode 0 Max
Mode 2 Max
Mode 1, 3 Max
Mode 1, 3
1.67 MHz
625 k
104.2 k
19.2 k
9.6 k
4.8 k
2.4 k
1.2 k
137.5
110
110
3.34 MHz
1250 k
208.4 k
38.4 k
19.2 k
9.6 k
4.8 k
2.4 k
275
220
220
fOSC
SMOD
20 MHz
20 MHz
20 MHz
11.059 MHz
11.059 MHz
11.059 MHz
11.059 MHz
11.059 MHz
11.986 MHz
6 MHz
12 MHz
X
1
1
1
0
0
0
0
0
0
0
C/T
Mode
Reload Value
X
X
0
0
0
0
0
0
0
0
0
X
X
2
2
2
2
2
2
2
2
1
X
X
FFH
FDH
FDH
FAH
F4H
E8H
1DH
72H
FEEBH
Figure 8. Timer 1 Generated Commonly Used Baud Rates
More About Mode 0
Serial data enters and exits through RxD. TxD outputs the shift
clock. 8 bits are transmitted/received: 8 data bits (LSB first). The
baud rate is fixed a 1/12 the oscillator frequency (12-clock mode) or
1/6 the oscillator frequency (6-clock mode).
S6P2 of every machine cycle in which SEND is active, the contents
of the transmit shift are shifted to the right one position.
As data bits shift out to the right, zeros come in from the left. When
the MSB of the data byte is at the output position of the shift register,
then the 1 that was initially loaded into the 9th position, is just to the
left of the MSB, and all positions to the left of that contain zeros.
This condition flags the TX Control block to do one last shift and
then deactivate SEND and set T1. Both of these actions occur at
S1P1 of the 10th machine cycle after “write to SBUF.”
Figure 9 shows a simplified functional diagram of the serial port in
Mode 0, and associated timing.
Transmission is initiated by any instruction that uses SBUF as a
destination register. The “write to SBUF” signal at S6P2 also loads a
1 into the 9th position of the transmit shift register and tells the TX
Control block to commence a transmission. The internal timing is
such that one full machine cycle will elapse between “write to SBUF”
and activation of SEND.
Reception is initiated by the condition REN = 1 and R1 = 0. At S6P2
of the next machine cycle, the RX Control unit writes the bits
11111110 to the receive shift register, and in the next clock phase
activates RECEIVE.
RECEIVE enable SHIFT CLOCK to the alternate output function line
of P3.1. SHIFT CLOCK makes transitions at S3P1 and S6P1 of
every machine cycle. At S6P2 of every machine cycle in which
RECEIVE is active, the contents of the receive shift register are
SEND enables the output of the shift register to the alternate output
function line of P3.0 and also enable SHIFT CLOCK to the alternate
output function line of P3.1. SHIFT CLOCK is low during S3, S4, and
S5 of every machine cycle, and high during S6, S1, and S2. At
2003 Jan 24
22
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
shifted to the left one position. The value that comes in from the right
is the value that was sampled at the P3.0 pin at S5P2 of the same
machine cycle.
whether the above conditions are met or not, the unit goes back to
looking for a 1-to-0 transition in RxD.
More About Modes 2 and 3
Eleven bits are transmitted (through TxD), or received (through
RxD): a start bit (0), 8 data bits (LSB first), a programmable 9th data
bit, and a stop bit (1). On transmit, the 9th data bit (TB8) can be
assigned the value of 0 or 1. On receive, the 9the data bit goes into
RB8 in SCON. The baud rate is programmable to either 1/32 or 1/64
(12-clock mode) or 1/16 or 1/32 the oscillator frequency (6-clock
mode) the oscillator frequency in Mode 2. Mode 3 may have a
variable baud rate generated from Timer 1 or Timer 2.
As data bits come in from the right, 1s shift out to the left. When the
0 that was initially loaded into the rightmost position arrives at the
leftmost position in the shift register, it flags the RX Control block to
do one last shift and load SBUF. At S1P1 of the 10th machine cycle
after the write to SCON that cleared RI, RECEIVE is cleared as RI is
set.
More About Mode 1
Ten bits are transmitted (through TxD), or received (through RxD): a
start bit (0), 8 data bits (LSB first), and a stop bit (1). On receive, the
stop bit goes into RB8 in SCON. In the 80C51 the baud rate is
determined by the Timer 1 or Timer 2 overflow rate.
Figures 11 and 12 show a functional diagram of the serial port in
Modes 2 and 3. The receive portion is exactly the same as in Mode
1. The transmit portion differs from Mode 1 only in the 9th bit of the
transmit shift register.
Figure 10 shows a simplified functional diagram of the serial port in
Mode 1, and associated timings for transmit receive.
Transmission is initiated by any instruction that uses SBUF as a
destination register. The “write to SBUF” signal also loads TB8 into
the 9th bit position of the transmit shift register and flags the TX
Control unit that a transmission is requested. Transmission
commences at S1P1 of the machine cycle following the next rollover
in the divide-by-16 counter. (Thus, the bit times are synchronized to
the divide-by-16 counter, not to the “write to SBUF” signal.)
Transmission is initiated by any instruction that uses SBUF as a
destination register. The “write to SBUF” signal also loads a 1 into
the 9th bit position of the transmit shift register and flags the TX
Control unit that a transmission is requested. Transmission actually
commences at S1P1 of the machine cycle following the next rollover
in the divide-by-16 counter. (Thus, the bit times are synchronized to
the divide-by-16 counter, not to the “write to SBUF” signal.)
The transmission begins with activation of SEND, which puts the
start bit at TxD. One bit time later, DATA is activated, which enables
the output bit of the transmit shift register to TxD. The first shift pulse
occurs one bit time after that. The first shift clocks a 1 (the stop bit)
into the 9th bit position of the shift register. Thereafter, only zeros
are clocked in. Thus, as data bits shift out to the right, zeros are
clocked in from the left. When TB8 is at the output position of the
shift register, then the stop bit is just to the left of TB8, and all
positions to the left of that contain zeros. This condition flags the TX
Control unit to do one last shift and then deactivate SEND and set
TI. This occurs at the 11th divide-by-16 rollover after “write to SUBF.”
The transmission begins with activation of SEND which puts the
start bit at TxD. One bit time later, DATA is activated, which enables
the output bit of the transmit shift register to TxD. The first shift pulse
occurs one bit time after that.
As data bits shift out to the right, zeros are clocked in from the left.
When the MSB of the data byte is at the output position of the shift
register, then the 1 that was initially loaded into the 9th position is
just to the left of the MSB, and all positions to the left of that contain
zeros. This condition flags the TX Control unit to do one last shift
and then deactivate SEND and set TI. This occurs at the 10th
divide-by-16 rollover after “write to SBUF.”
Reception is initiated by a detected 1-to-0 transition at RxD. For this
purpose RxD is sampled at a rate of 16 times whatever baud rate
has been established. When a transition is detected, the
divide-by-16 counter is immediately reset, and 1FFH is written to the
input shift register.
Reception is initiated by a detected 1-to-0 transition at RxD. For this
purpose RxD is sampled at a rate of 16 times whatever baud rate
has been established. When a transition is detected, the
divide-by-16 counter is immediately reset, and 1FFH is written into
the input shift register. Resetting the divide-by-16 counter aligns its
rollovers with the boundaries of the incoming bit times.
At the 7th, 8th, and 9th counter states of each bit time, the bit
detector samples the value of R-D. The value accepted is the value
that was seen in at least 2 of the 3 samples. If the value accepted
during the first bit time is not 0, the receive circuits are reset and the
unit goes back to looking for another 1-to-0 transition. If the start bit
proves valid, it is shifted into the input shift register, and reception of
the rest of the frame will proceed.
The 16 states of the counter divide each bit time into 16ths. At the
7th, 8th, and 9th counter states of each bit time, the bit detector
samples the value of RxD. The value accepted is the value that was
seen in at least 2 of the 3 samples. This is done for noise rejection.
If the value accepted during the first bit time is not 0, the receive
circuits are reset and the unit goes back to looking for another 1-to-0
transition. This is to provide rejection of false start bits. If the start bit
proves valid, it is shifted into the input shift register, and reception of
the rest of the frame will proceed.
As data bits come in from the right, 1s shift out to the left. When the
start bit arrives at the leftmost position in the shift register (which in
Modes 2 and 3 is a 9-bit register), it flags the RX Control block to do
one last shift, load SBUF and RB8, and set RI.
The signal to load SBUF and RB8, and to set RI, will be generated
if, and only if, the following conditions are met at the time the final
shift pulse is generated.
1. RI = 0, and
2. Either SM2 = 0, or the received 9th data bit = 1.
As data bits come in from the right, 1s shift out to the left. When the
start bit arrives at the leftmost position in the shift register (which in
mode 1 is a 9-bit register), it flags the RX Control block to do one
last shift, load SBUF and RB8, and set RI. The signal to load SBUF
and RB8, and to set RI, will be generated if, and only if, the following
conditions are met at the time the final shift pulse is generated.:
1. R1 = 0, and
2. Either SM2 = 0, or the received stop bit = 1.
If either of these conditions is not met, the received frame is
irretrievably lost, and RI is not set. If both conditions are met, the
received 9th data bit goes into RB8, and the first 8 data bits go into
SBUF. One bit time later, whether the above conditions were met or
not, the unit goes back to looking for a 1-to-0 transition at the RxD
input.
If either of these two conditions is not met, the received frame is
irretrievably lost. If both conditions are met, the stop bit goes into
RB8, the 8 data bits go into SBUF, and RI is activated. At this time,
2003 Jan 24
P87C51RA2/RB2/RC2/RD2
23
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
80C51 Internal Bus
Write
to
SBUF
S
D
Q
RxD
P3.0 Alt
Output
Function
SBUF
CL
Zero Detector
Start
Shift
TX Control
S6
T1
TX Clock
Send
Serial
Port
Interrupt
R1
RX Clock
Receive
RX Control
REN
RI
Start
1
1
1
TxD
P3.1 Alt
Output
Function
Shift
Clock
Shift
1
1
1
1
0
MSB
LSB
RxD
P3.0 Alt
Input
Function
Input Shift Register
Shift
Load
SBUF
LSB
MSB
SBUF
Read
SBUF
80C51 Internal Bus
S4 . .
S1 . . . . S6 S1 . . . . S6 S1 . . . . S6 S1 . . . . S6 S1 . . . . S6 S1 . . . . S6 S1 . . . . S6 S1 . . . . S6 S1 . . . . S6 S1 . . . . S6 S1
ALE
Write to SBUF
S6P2
Send
Shift
Transmit
RxD (Data Out)
D0
D1
D2
D3
D4
D5
D6
D7
TxD (Shift Clock)
S3P1
TI
S6P1
Write to SCON (Clear RI)
RI
Receive
Shift
RxD (Data In)
Receive
D0
D1
D2
D3
D4
D5
D6
D7
S5P2
TxD (Shift Clock)
SU00539
Figure 9. Serial Port Mode 0
2003 Jan 24
24
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
Timer 1
Overflow
80C51 Internal Bus
TB8
÷2
SMOD = 0
SMOD = 1
Write
to
SBUF
S
D
Q
SBUF
TxD
CL
Zero Detector
Start
Data
Shift
TX Control
÷ 16
T1
Send
RX Clock RI
Load
SBUF
TX Clock
Serial
Port
Interrupt
÷ 16
Sample
RX Control
1-to-0
Transition
Detector
Shift
Start
1FFH
Bit Detector
Input Shift Register
(9 Bits)
Shift
RxD
Load
SBUF
SBUF
Read
SBUF
80C51 Internal Bus
TX
Clock
Write to SBUF
Send
Data
S1P1
Transmit
Shift
TxD
Start Bit
D0
D1
D2
D3
D4
D5
D6
D7
Stop Bit
D0
D1
D2
D3
D4
D5
D6
D7
Stop Bit
TI
÷ 16 Reset
RX
Clock
RxD
Bit Detector
Sample Times
Start
Bit
Receive
Shift
RI
SU00540
Figure 10. Serial Port Mode 1
2003 Jan 24
25
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
80C51 Internal Bus
TB8
Write
to
SBUF
S
D
Q
SBUF
TxD
CL
Phase 2 Clock
(1/2 fOSC)
Zero Detector
Mode 2
Start
÷ 16
SMOD = 1
Stop Bit
Gen.
TX Control
TX Clock
Shift
Data
T1
Send
R1
Load
SBUF
Serial
Port
Interrupt
÷2
SMOD = 0
(SMOD is
PCON.7)
÷ 16
RX Clock
Sample
RX Control
1-to-0
Transition
Detector
Shift
Start
1FFH
Bit Detector
Input Shift Register
(9 Bits)
Shift
RxD
Load
SBUF
SBUF
Read
SBUF
80C51 Internal Bus
TX
Clock
Write to SBUF
Send
Data
S1P1
Transmit
Shift
TxD
Start Bit
D0
D1
D2
D3
D4
D5
D6
D7
TB8
D0
D1
D2
D3
D4
D5
D6
D7
RB8
Stop Bit
TI
Stop Bit Gen.
÷ 16 Reset
RX
Clock
RxD
Bit Detector
Sample Times
Start
Bit
Stop Bit
Receive
Shift
RI
SU00541
Figure 11. Serial Port Mode 2
2003 Jan 24
26
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
Timer 1
Overflow
80C51 Internal Bus
TB8
Write
to
SBUF
÷2
SMOD = 0
SMOD = 1
S
D
Q
SBUF
TxD
CL
Zero Detector
Start
Data
Shift
TX Control
÷ 16
TX Clock
T1
Send
R1
Load
SBUF
Serial
Port
Interrupt
÷ 16
RX Clock
Sample
RX Control
1-to-0
Transition
Detector
Shift
Start
1FFH
Bit Detector
Input Shift Register
(9 Bits)
Shift
RxD
Load
SBUF
SBUF
Read
SBUF
80C51 Internal Bus
TX
Clock
Write to SBUF
Send
Data
S1P1
Transmit
Shift
TxD
Start Bit
D0
D1
D2
D3
D4
D5
D6
D7
TB8
D0
D1
D2
D3
D4
D5
D6
D7
RB8
Stop Bit
TI
Stop Bit Gen.
RX
Clock
RxD
Bit Detector
Sample Times
÷ 16 Reset
Start
Bit
Stop Bit
Receive
Shift
RI
SU00542
Figure 12. Serial Port Mode 3
2003 Jan 24
27
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
Slave 1
Enhanced Features
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:
2003 Jan 24
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 14.
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 13.
Slave 0
P87C51RA2/RB2/RC2/RD2
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
28
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
D0
D1
D2
D3
D4
D5
D6
D7
D8
DATA BYTE
START
BIT
ONLY IN
MODE 2, 3
STOP
BIT
SET FE BIT IF STOP BIT IS 0 (FRAMING ERROR)
SM0 TO UART MODE CONTROL
SM0 / FE
SM1
SM2
REN
TB8
RB8
TI
RI
SCON
(98H)
SMOD1
SMOD0
–
POF
LVF
GF0
GF1
IDL
PCON
(87H)
0 : SCON.7 = SM0
1 : SCON.7 = FE
SU00044
Figure 13. 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 14. UART Multiprocessor Communication, Automatic Address Recognition
2003 Jan 24
29
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
The priority scheme for servicing the interrupts is the same as that
for the 80C51, except there are four interrupt levels rather than two
as on the 80C51. 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 P87C51RA2/RB2/RC2/RD2 has 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 15, 16, and 17.) 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 17.
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
X0
1
IE0
HARDWARE CLEAR?
N (L)1
Y (T)2
VECTOR ADDRESS
03H
T0
2
TP0
Y
0BH
X1
3
IE1
N (L) Y (T)
13H
T1
4
TF1
Y
1BH
PCA
5
CF, CCFn
n = 0–4
N
33H
SP
6
RI, TI
N
23H
T2
7
TF2, EXF2
N
2BH
NOTES:
1. L = Level activated
2. T = Transition activated
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.
SU01290
Figure 15. IE Registers
2003 Jan 24
30
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
IP (0B8H)
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
–
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.
SU01291
Figure 16. 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
–
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.
SU01292
Figure 17. IPH Registers
2003 Jan 24
31
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
The GF2 bit is a general purpose user-defined flag. Note that bit 2 is
not writable and is always read as a zero. This allows the DPS bit to
be quickly toggled simply by executing an INC AUXR1 instruction
without affecting the GF2 bit.
Reduced EMI Mode
The AO bit (AUXR.0) in the AUXR register when set disables the
ALE output unless the CPU needs to perform an off-chip memory
access.
Reduced EMI Mode
AUXR (8EH)
DPS
7
6
5
4
3
2
1
0
–
–
–
–
–
–
EXTRAM
AO
AUXR.1
AUXR.0
BIT0
AUXR1
DPTR1
DPTR0
EXTRAM
AO
DPH
(83H)
DPL
(82H)
See more detailed description in Figure 32.
EXTERNAL
DATA
MEMORY
SU00745A
Dual DPTR
The dual DPTR structure (see Figure 18) 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.
Figure 18.
DPTR Instructions
The instructions that refer to DPTR refer to the data pointer that is
currently selected using the AUXR1/bit 0 register. The six
instructions that use the DPTR are as follows:
• New Register Name: AUXR1#
• SFR Address: A2H
• Reset Value: xxxxxxx0B
AUXR1 (A2H)
7
6
5
4
3
2
1
0
–
–
–
–
GF2
0
–
DPS
Where:
DPS = AUXR1/bit0 = Switches between DPTR0 and DPTR1.
Select Reg
DPS
DPTR0
0
DPTR1
1
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 DPS bit status should be saved by software when switching
between DPTR0 and DPTR1.
2003 Jan 24
INC DPTR
32
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
the PCA counter overflows and an interrupt will be generated if the
ECF bit in the CMOD register is set, The CF bit can only be cleared
by software. Bits 0 through 4 of the CCON register are the flags for
the modules (bit 0 for module 0, bit 1 for module 1, etc.) and are set
by hardware when either a match or a capture occurs. These flags
also can only be cleared by software. The PCA interrupt system
shown in Figure 21.
Programmable Counter Array (PCA)
The Programmable Counter Array available on the
P87C51RA2/RB2/RC2/RD2 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 19.
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 24). 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: 1/6 the oscillator frequency, 1/2 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 22):
CPS1 CPS0 PCA Timer Count Source
0
0
1/6 oscillator frequency (6-clock mode);
1/12 oscillator frequency (12-clock mode)
0
1
1/2 oscillator frequency (6-clock mode);
1/4 oscillator frequency (12-clock mode)
1
0
Timer 0 overflow
1
1
External Input at ECI pin
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 25
shows the CCAPMn settings for the various PCA functions.
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 20.
The watchdog timer function is implemented in module 4 (see
Figure 29).
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 23).
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
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 19. Programmable Counter Array (PCA)
2003 Jan 24
33
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
TO PCA
MODULES
OSC/6 (6 CLOCK MODE)
OR
OSC/12 (12 CLOCK MODE)
OSC/2 (6 CLOCK MODE)
OR
OSC/4 (12 CLOCK MODE)
OVERFLOW
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
(C1H)
CR
––
CCF4
CCF3
CCF2
CCF1
CCF0
CCON
(C0H)
SU01256
Figure 20. PCA Timer/Counter
CF
CR
––
CCF4
CCF3
CCF2
CCF1
CCF0
CCON
(C0H)
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
SU01097
Figure 21. PCA Interrupt System
2003 Jan 24
34
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
CMOD Address = D9H
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
0
1
2
3
Internal clock, fOSC/6 in 6-clock mode (fOSC/12 in 12-clock mode)
Internal clock, fOSC/2 in 6-clock mode (fOSC/4 in 12-clock mode)
Timer 0 overflow
External clock at ECI/P1.2 pin
(max. rate = fOSC/4 in 6-clock mode, fOCS/8 in 12-clock mode)
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
SU01318
Figure 22. CMOD: PCA Counter Mode Register
CCON Address = D8H
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.
SU01319
Figure 23. CCON: PCA Counter Control Register
2003 Jan 24
35
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
CCAPMn Address
CCAPM0
CCAPM1
CCAPM2
CCAPM3
CCAPM4
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.
SU01320
Figure 24. 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 25. 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 26.
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 28).
Pulse Width Modulator Mode
All of the PCA modules can be used as PWM outputs. Figure 29
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 27).
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
2003 Jan 24
36
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
CF
CR
––
CCF4
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)
SU01608
Figure 26. 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)
SU01609
Figure 27. PCA Compare Mode
2003 Jan 24
37
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
CF
WRITE TO
CCAPnH
CR
CCF4
CCF3
CCF2
CCF1
CCON
(D8H)
CCF0
RESET
CCAPnH
WRITE TO
CCAPnL
0
––
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
SU01610
Figure 28. 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
SU01611
Figure 29. PCA PWM Mode
2003 Jan 24
38
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
CIDL
WRITE TO
CCAP4L
––
––
––
CPS1
CPS0
ECF
CMOD
(D9H)
RESET
CCAP4H
WRITE TO
CCAP4H
1
WDTE
CCAP4L
MODULE 4
0
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)
SU01612
Figure 30. PCA Watchdog Timer mode (Module 4 only)
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.
PCA Watchdog Timer
An on-board watchdog timer is available with the PCA to improve the
reliability of the system without increasing chip count. Watchdog
timers are useful for systems that are susceptible to noise, power
glitches, or electrostatic discharge. Module 4 is the only PCA module
that can be programmed as a watchdog. However, this module can
still be used for other modes if the watchdog is not needed.
Figure 30 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 31 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 31.
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.
2003 Jan 24
39
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
INIT_WATCHDOG:
MOV CCAPM4, #4CH
MOV CCAP4L, #0FFH
MOV CCAP4H, #0FFH
ORL CMOD, #40H
;
;
;
;
;
;
;
;
P87C51RA2/RB2/RC2/RD2
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 31. PCA Watchdog Timer Initialization Code
2003 Jan 24
40
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
For example:
Expanded Data RAM Addressing
The P87C51RA2/RB2/RC2/RD2 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 expanded RAM (ERAM) (768 bytes for the RD2).
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 256/768 bytes of external
data memory in the P87C51RA2/RB2/RC2/RD2.
MOV @R0,acc
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 256/768-bytes expanded RAM (ERAM, 00H – 1FFH/2FFH)
are indirectly accessed by move external instruction, MOVX, and
with the EXTRAM bit cleared, see Figure 32.
MOVX @R0,acc
where R0 contains 0A0H, accesses the ERAM at address 0A0H
rather than external memory. An access to external data memory
locations higher than the ERAM 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 33.
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 (12-clock mode; 1/3 fOSC
in 6-clock mode).
1
ALE is active only during off-chip memory access.
EXTRAM
Internal/External RAM access using MOVX @Ri/@DPTR
EXTRAM
Operating Mode
0
Internal ERAM 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.
SU01613
Figure 32. AUXR: Auxiliary Register
2003 Jan 24
41
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
FF
FF
UPPER
128 BYTES
INTERNAL RAM
ERAM
256 or 768 BYTES
80
FFFF
SPECIAL
FUNCTION
REGISTER
EXTERNAL
DATA
MEMORY
80
LOWER
128 BYTES
INTERNAL RAM
100
00
00
0000
SU01293
Figure 33. Internal and External Data Memory Address Space with EXTRAM = 0
HARDWARE WATCHDOG TIMER (ONE-TIME
ENABLED WITH RESET-OUT FOR
P87C51RA2/RB2/RC2/RD2)
Using the WDT
To enable the WDT, the user must write 01EH and 0E1H in sequence
to the WDTRST, SFR location 0A6H. When the WDT is enabled, the
user needs to service it by writing 01EH and 0E1H to WDTRST to
avoid a WDT overflow. The 14-bit counter overflows when it reaches
16383 (3FFFH) and this will reset the device. When the 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 the WDT overflows, it will
generate an output RESET pulse at the reset pin (see note below).
The RESET pulse duration is 98 × TOSC (6-clock mode; 196 in
12-clock mode), 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.
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, the user must write
01EH and 0E1H in sequence to the WDTRST, SFR location 0A6H.
When the 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 the WDT overflows, it will drive an output reset HIGH
pulse at the RST-pin (see the note below).
2003 Jan 24
42
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
ABSOLUTE MAXIMUM RATINGS1, 2, 3
PARAMETER
Operating temperature under bias
RATING
UNIT
0 to +70 or –40 to +85
°C
–65 to +150
°C
0 to +13.0
V
Storage temperature range
Voltage on EA/VPP pin to VSS
Voltage on any other pin to VSS
4
Maximum IOL per I/O pin
–0.5 to +6.0
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.
4. Transient voltage only.
AC ELECTRICAL CHARACTERISTICS
Tamb = 0°C to +70°C or –40°C to +85°C
CLOCK FREQUENCY
RANGE
SYMBOL
1/tCLCL
2003 Jan 24
FIGURE
PARAMETER
38
Oscillator frequency
OPERATING MODE
POWER SUPPLY
VOLTAGE
MAX
UNIT
6-clock
5V
0
30
MHz
6-clock
2.7 V to 5.5 V
0
16
MHz
12-clock
5V
0
33
MHz
12-clock
2.7 V to 5.5 V
0
16
MHz
43
10%
MIN
10%
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
DC ELECTRICAL CHARACTERISTICS
Tamb = 0 °C to +70 °C or –40 °C to +85 °C; VCC = 2.7 V to 5.5 V; VSS = 0 V (16 MHz max. CPU clock)
SYMBOL
PARAMETER
TEST
CONDITIONS
LIMITS
MIN
VIL
Input low
voltage11
UNIT
TYP1
MAX
4.0 V < VCC < 5.5 V
–0.5
0.2 VCC–0.1
V
2.7 V < VCC < 4.0 V
–0.5
0.7 VCC
V
VIH
Input high voltage (ports 0, 1, 2, 3, EA)
0.2 VCC+0.9
VCC+0.5
V
VIH1
Input high voltage, XTAL1, RST11
0.7 VCC
VCC+0.5
V
VOL
Output low voltage, ports 1, 2, 8
VCC = 2.7 V; IOL = 1.6 mA2
–
0.4
V
VOL1
Output low voltage, port 0, ALE, PSEN8, 7
VCC = 2.7 V; IOL = 3.2 mA2
–
0.4
V
VCC = 2.7 V; IOH = –20 mA
VCC – 0.7
–
V
VCC = 4.5 V; IOH = –30 mA
VCC – 0.7
–
V
VOH
Output high voltage, ports 1, 2, 3
3
VOH1
Output high voltage (port 0 in external bus VCC = 2.7 V; IOH = –3.2 mA
mode), ALE9, PSEN3
VCC – 0.7
–
V
IIL
Logical 0 input current, ports 1, 2, 3
VIN = 0.4 V
–1
–50
mA
ITL
Logical 1-to-0 transition current, ports 1, 2, 36
VIN = 2.0 V; See note 4
–
–650
mA
ILI
Input leakage current, port 0
0.45 < VIN < VCC – 0.3
–
±10
mA
ICC
Power supply current (see Figure 41 and
Source Code):
Active mode @ 16 MHz
mA
Idle mode @ 16 MHz
mA
Power-down mode or clock stopped
(see Figure 37 for conditions) 12
Tamb = 0 °C to 70 °C
2
30
mA
Tamb = –40 °C to +85 °C
3
50
mA
VRAM
RAM keep-alive voltage
1.2
RRST
Internal reset pull-down resistor
40
225
V
kΩ
CIO
Pin capacitance10 (except EA)
–
15
pF
NOTES:
1. Typical ratings are not guaranteed. Values listed are based on tests conducted on limited number of samples at room temperature.
2. Capacitive loading on ports 0 and 2 may cause spurious noise to be superimposed on the VOLs of ALE and ports 1 and 3. The noise is
due to external bus capacitance discharging into the port 0 and port 2 pins when these pins make 1-to-0 transitions during bus operations.
In 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 43 through 46 for ICC test conditions and Figure 41 for ICC vs. Frequency
12-clock mode characteristics:
Active mode (operating): ICC = 1.0 mA + 1.1 mA × FREQ.[MHz]
Active mode (reset):
ICC = 7.0 mA + 0.6 mA
FREQ.[MHz]
FREQ.[MHz]
Idle mode:
ICC = 1.0 mA + 0.22 mA
6. This value applies to Tamb = 0 °C to +70 °C. For Tamb = –40 °C to +85 °C, ITL = –750 mA.
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:
15 mA (*NOTE: This is 85 °C specification.)
Maximum IOL per port pin:
Maximum IOL per 8-bit port:
26 mA
71 mA
Maximum total IOL for all outputs:
If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater than the listed
test conditions.
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).
11. To improve noise rejection a nominal 100 ns glitch rejection circuitry has been added to the RST pin, and a nominal 15 ns glitch rejection
circuitry has been added to the INT0 and INT1 pins. Previous devices provided only an inherent 5 ns of glitch rejection.
12. Power down mode for 3 V range: Commercial Temperature Range – typ: 0.5 mA, max. 20 mA; Industrial Temperature Range – typ. 1.0 mA,
max. 30 mA;
2003 Jan 24
44
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
DC ELECTRICAL CHARACTERISTICS
Tamb = 0 °C to +70 °C or –40 °C to +85 °C; VCC = 5 V ±10%; VSS = 0 V (30/33 MHz max. CPU clock)
SYMBOL
PARAMETER
TEST
CONDITIONS
LIMITS
MIN
VIL
Input low voltage11
VIH
Input high voltage (ports 0, 1, 2, 3, EA)
4.5 V < VCC < 5.5 V
RST11
UNIT
TYP1
MAX
–0.5
0.2 VCC–0.1
V
0.2 VCC+0.9
VCC+0.5
V
VIH1
Input high voltage, XTAL1,
0.7 VCC
VCC+0.5
V
VOL
Output low voltage, ports 1, 2, 3 8
VCC = 4.5 V; IOL = 1.6 mA2
–
0.4
V
VOL1
Output low voltage, port 0, ALE, PSEN 7, 8
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 mA
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
–50
mA
ITL
Logical 1-to-0 transition current, ports 1, 2, 36
VIN = 2.0 V; See note 4
–
–650
mA
ILI
Input leakage current, port 0
0.45 < VIN < VCC – 0.3
–
±10
mA
ICC
Power supply current
Active mode (see Note 5)
Idle mode (see Note 5)
Power-down mode or clock stopped
(see Figure 46 for conditions)
Tamb = 0 °C to 70 °C
2
30
mA
Tamb = –40 °C to +85 °C
3
50
mA
VRAM
RAM keep-alive voltage
1.2
RRST
Internal reset pull-down resistor
40
225
V
kΩ
CIO
Pin capacitance10 (except EA)
–
15
pF
NOTES:
1. Typical ratings are not guaranteed. The values listed are at room temperature, 5 V.
2. Capacitive loading on ports 0 and 2 may cause spurious noise to be superimposed on the 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 43 through 46 for ICC test conditions and Figure 41 for ICC vs. Frequency.
12-clock mode characteristics:
Active mode (operating): ICC = 1.0 mA + 1.1 mA × FREQ.[MHz]
Active mode (reset):
ICC = 7.0 mA + 0.6 mA
FREQ.[MHz]
FREQ.[MHz]
Idle mode:
ICC = 1.0 mA + 0.22 mA
6. This value applies to Tamb = 0°C to +70°C. For Tamb = –40°C to +85°C, ITL = –750 µΑ.
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).
11. To improve noise rejection a nominal 100 ns glitch rejection circuitry has been added to the RST pin, and a nominal 15 ns glitch rejection
circuitry has been added to the INT0 and INT1 pins. Previous devices provided only an inherent 5 ns of glitch rejection.
2003 Jan 24
45
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
AC ELECTRICAL CHARACTERISTICS (12-CLOCK MODE, 5 V ±10% OPERATION)
Tamb = 0 °C to +70 °C or –40 °C to +85 °C ; VCC = 5 V ±10%, VSS = 0 V1,2,3,4
Symbol
Figure
Parameter
Limits
16 MHz Clock
MIN
MAX
33
MIN
Unit
MAX
1/tCLCL
38
Oscillator frequency
0
tLHLL
34
ALE pulse width
2 tCLCL–8
117
MHz
ns
tAVLL
34
Address valid to ALE low
tCLCL –13
49.5
ns
tLLAX
34
Address hold after ALE low
tCLCL –20
tLLIV
34
ALE low to valid instruction in
tLLPL
34
ALE low to PSEN low
tCLCL –10
52.5
ns
tPLPH
34
PSEN pulse width
3 tCLCL –10
177.5
ns
tPLIV
34
PSEN low to valid instruction in
tPXIX
34
Input instruction hold after PSEN
tPXIZ
34
Input instruction float after PSEN
tCLCL –10
52.5
ns
tAVIV
34
Address to valid instruction in
5 tCLCL –35
277.5
ns
tPLAZ
34
PSEN low to address float
10
10
ns
42.5
4 tCLCL –35
3 tCLCL –35
0
ns
215
152.5
0
ns
ns
ns
Data Memory
tRLRH
35
RD pulse width
6 tCLCL –20
355
tWLWH
36
WR pulse width
6 tCLCL –20
355
tRLDV
35
RD low to valid data in
tRHDX
35
Data hold after RD
tRHDZ
35
Data float after RD
2 tCLCL –10
115
ns
tLLDV
35
ALE low to valid data in
8 tCLCL –35
465
ns
tAVDV
35
Address to valid data in
9 tCLCL –35
527.5
ns
tLLWL
35, 36
ALE low to RD or WR low
3 tCLCL –15
202.5
ns
tAVWL
35, 36
Address valid to WR low or RD low
4 tCLCL –15
235
ns
tQVWX
36
Data valid to WR transition
tCLCL –25
37.5
ns
tWHQX
36
Data hold after WR
tCLCL –15
47.5
ns
tQVWH
36
Data valid to WR high
7 tCLCL –5
tRLAZ
35
RD low to address float
tWHLH
35, 36
RD or WR high to ALE high
tCLCL –10
tCLCL +10
5 tCLCL –35
0
ns
ns
277.5
0
3 tCLCL +15
172.5
ns
432.5
0
52.5
ns
ns
0
ns
72.5
ns
External Clock
tCHCX
38
High time
0.32 tCLCL
tCLCL – tCLCX
ns
tCLCX
38
Low time
0.32 tCLCL
tCLCL – tCHCX
ns
tCLCH
38
Rise time
5
ns
tCHCL
38
Fall time
5
ns
Shift register
tXLXL
37
Serial port clock cycle time
12 tCLCL
750
ns
tQVXH
37
Output data setup to clock rising edge
10 tCLCL –25
600
ns
tXHQX
37
Output data hold after clock rising edge
2 tCLCL –15
110
ns
tXHDX
37
Input data hold after clock rising edge
0
0
ns
tXHDV
37
Clock rising edge to input data
valid5
10 tCLCL –133
492
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 outputs = 80 pF
3. Interfacing the microcontroller to devices with float time up to 45 ns is permitted. This limited bus contention will not cause damage to port 0
drivers.
4. Parts are guaranteed by design to operate down to 0 Hz.
5. Below 16 MHz this parameter is 8 tCLCL – 133.
2003 Jan 24
46
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
AC ELECTRICAL CHARACTERISTICS (12-CLOCK MODE, 2.7 V TO 5.5 V OPERATION)
Tamb = 0 °C to +70 °C or –40 °C to +85 °C ; VCC = 2.7 V to 5.5 V, VSS = 0 V1,2,3,4
Symbol
Figure
Parameter
Limits
16 MHz Clock
MIN
MAX
16
MIN
Unit
MAX
1/tCLCL
38
Oscillator frequency
0
tLHLL
34
ALE pulse width
2tCLCL–10
115
MHz
ns
tAVLL
34
Address valid to ALE low
tCLCL –15
47.5
ns
tLLAX
34
Address hold after ALE low
tCLCL –25
tLLIV
34
ALE low to valid instruction in
tLLPL
34
ALE low to PSEN low
tCLCL –15
47.5
ns
tPLPH
34
PSEN pulse width
3 tCLCL –15
172.5
ns
tPLIV
34
PSEN low to valid instruction in
tPXIX
34
Input instruction hold after PSEN
tPXIZ
34
Input instruction float after PSEN
tCLCL –10
52.5
ns
tAVIV
34
Address to valid instruction in
5 tCLCL –50
262.5
ns
tPLAZ
34
PSEN low to address float
10
10
ns
37.5
4 tCLCL –55
3 tCLCL –55
0
ns
195
132.5
0
ns
ns
ns
Data Memory
tRLRH
35
RD pulse width
6 tCLCL –25
350
tWLWH
36
WR pulse width
6 tCLCL –25
350
tRLDV
35
RD low to valid data in
tRHDX
35
Data hold after RD
tRHDZ
35
Data float after RD
2 tCLCL –20
105
ns
tLLDV
35
ALE low to valid data in
8 tCLCL –55
445
ns
tAVDV
35
Address to valid data in
9 tCLCL –50
512.5
ns
tLLWL
35, 36
ALE low to RD or WR low
3 tCLCL –20
207.5
ns
tAVWL
35, 36
Address valid to WR low or RD low
4 tCLCL –20
230
ns
tQVWX
36
Data valid to WR transition
tCLCL –30
32.5
ns
tWHQX
36
Data hold after WR
tCLCL –20
42.5
ns
tQVWH
36
Data valid to WR high
7 tCLCL –10
tRLAZ
35
RD low to address float
tWHLH
35, 36
RD or WR high to ALE high
tCLCL –15
tCLCL +15
5 tCLCL –50
0
ns
ns
262.5
0
3 tCLCL +20
167.5
ns
427.5
0
47.5
ns
ns
0
ns
77.5
ns
External Clock
tCHCX
38
High time
0.32 tCLCL
tCLCL – tCLCX
ns
tCLCX
38
Low time
0.32 tCLCL
tCLCL – tCHCX
ns
tCLCH
38
Rise time
5
ns
tCHCL
38
Fall time
5
ns
Shift register
tXLXL
37
Serial port clock cycle time
12 tCLCL
750
ns
tQVXH
37
Output data setup to clock rising edge
10 tCLCL –25
600
ns
tXHQX
37
Output data hold after clock rising edge
2 tCLCL –15
110
ns
tXHDX
37
Input data hold after clock rising edge
0
0
ns
tXHDV
37
Clock rising edge to input data
valid5
10 tCLCL –133
492
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 outputs = 80 pF
3. Interfacing the microcontroller to devices with float time up to 45 ns is permitted. This limited bus contention will not cause damage to port 0
drivers.
4. Parts are guaranteed by design to operate down to 0 Hz.
5. Below 16 MHz this parameter is 8 tCLCL – 133.
2003 Jan 24
47
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
AC ELECTRICAL CHARACTERISTICS (6-CLOCK MODE, 5 V ±10% OPERATION)
Tamb = 0 °C to +70 °C or –40 °C to +85 °C ; VCC = 5 V ±10%, VSS = 0 V1,2,3,4,5
Symbol
Figure
Parameter
Limits
16 MHz Clock
MIN
MAX
30
MIN
Unit
MAX
1/tCLCL
38
Oscillator frequency
0
tLHLL
34
ALE pulse width
tCLCL–8
54.5
MHz
ns
tAVLL
34
Address valid to ALE low
0.5 tCLCL –13
18.25
ns
tLLAX
34
Address hold after ALE low
0.5 tCLCL –20
tLLIV
34
ALE low to valid instruction in
tLLPL
34
ALE low to PSEN low
0.5 tCLCL –10
21.25
ns
tPLPH
34
PSEN pulse width
1.5 tCLCL –10
83.75
ns
tPLIV
34
PSEN low to valid instruction in
tPXIX
34
Input instruction hold after PSEN
tPXIZ
34
Input instruction float after PSEN
0.5 tCLCL –10
21.25
ns
tAVIV
34
Address to valid instruction in
2.5 tCLCL –35
121.25
ns
tPLAZ
34
Data Memory
PSEN low to address float
10
10
ns
tRLRH
35
RD pulse width
3 tCLCL –20
tWLWH
36
WR pulse width
3 tCLCL –20
tRLDV
35
RD low to valid data in
tRHDX
35
Data hold after RD
tRHDZ
35
Data float after RD
tCLCL –10
52.5
ns
tLLDV
35
ALE low to valid data in
4 tCLCL –35
215
ns
tAVDV
35
Address to valid data in
4.5 tCLCL –35
246.25
ns
tLLWL
35, 36
ALE low to RD or WR low
1.5 tCLCL –15
108.75
ns
tAVWL
35, 36
Address valid to WR low or RD low
2 tCLCL –15
110
ns
tQVWX
36
Data valid to WR transition
0.5 tCLCL –25
6.25
ns
tWHQX
36
Data hold after WR
0.5 tCLCL –15
16.25
ns
tQVWH
36
Data valid to WR high
3.5 tCLCL –5
213.75
tRLAZ
35
RD low to address float
11.25
2 tCLCL –35
1.5 tCLCL –35
0
ns
90
58.75
0
ns
167.5
0
ns
121.25
0
1.5 tCLCL +15
78.75
0
21.25
ns
ns
167.5
2.5 tCLCL –35
ns
ns
ns
ns
0
ns
41.25
ns
tWHLH
35, 36
External Clock
RD or WR high to ALE high
0.5 tCLCL –10
0.5 tCLCL +10
tCHCX
38
High time
0.4 tCLCL
tCLCL – tCLCX
ns
tCLCX
38
Low time
0.4 tCLCL
tCLCL – tCHCX
ns
tCLCH
38
Rise time
5
ns
tCHCL
38
Shift register
Fall time
5
ns
tXLXL
37
Serial port clock cycle time
6 tCLCL
375
ns
tQVXH
37
Output data setup to clock rising edge
5 tCLCL –25
287.5
ns
tXHQX
37
Output data hold after clock rising edge
tCLCL –15
47.5
ns
tXHDX
37
Input data hold after clock rising edge
0
tXHDV
37
Clock rising edge to input data valid6
0
5 tCLCL –133
ns
179.5
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 outputs = 80 pF
3. Interfacing the microcontroller to devices with float time up to 45ns is permitted. This limited bus contention will not cause damage to port 0
drivers.
4. Parts are guaranteed by design to operate down to 0 Hz.
5. Data shown in the table are the best mathematical models for the set of measured values obtained in tests. If a particular parameter
calculated at a customer specified frequency has a negative value, it should be considered equal to zero.
6. Below 16 MHz this parameter is 4 tCLCL – 133
2003 Jan 24
48
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
AC ELECTRICAL CHARACTERISTICS (6-CLOCK MODE, 2.7 V TO 5.5 V OPERATION)
Tamb = 0 °C to +70 °C or –40 °C to +85 °C ; VCC=2.7 V to 5.5 V, VSS = 0 V1,2,3,4,5
Symbol
Figure
Parameter
Limits
16 MHz Clock
MIN
MAX
16
MIN
Unit
MAX
1/tCLCL
38
Oscillator frequency
0
tLHLL
34
ALE pulse width
tCLCL–10
52.5
MHz
ns
tAVLL
34
Address valid to ALE low
0.5 tCLCL –15
16.25
ns
tLLAX
34
Address hold after ALE low
0.5 tCLCL –25
tLLIV
34
ALE low to valid instruction in
tLLPL
34
ALE low to PSEN low
0.5 tCLCL –15
16.25
ns
tPLPH
34
PSEN pulse width
1.5 tCLCL –15
78.75
ns
tPLIV
34
PSEN low to valid instruction in
tPXIX
34
Input instruction hold after PSEN
tPXIZ
34
Input instruction float after PSEN
0.5 tCLCL –10
21.25
ns
tAVIV
34
Address to valid instruction in
2.5 tCLCL –50
101.25
ns
tPLAZ
34
Data Memory
PSEN low to address float
10
10
ns
tRLRH
35
RD pulse width
3 tCLCL –25
tWLWH
36
WR pulse width
3 tCLCL –25
tRLDV
35
RD low to valid data in
tRHDX
35
Data hold after RD
tRHDZ
35
Data float after RD
tCLCL –20
42.5
ns
tLLDV
35
ALE low to valid data in
4 tCLCL –55
195
ns
tAVDV
35
Address to valid data in
4.5 tCLCL –50
231.25
ns
tLLWL
35, 36
ALE low to RD or WR low
1.5 tCLCL –20
113.75
ns
tAVWL
35, 36
Address valid to WR low or RD low
2 tCLCL –20
105
ns
tQVWX
36
Data valid to WR transition
0.5 tCLCL –30
1.25
ns
tWHQX
36
Data hold after WR
0.5 tCLCL –20
11.25
ns
tQVWH
36
Data valid to WR high
3.5 tCLCL –10
208.75
tRLAZ
35
RD low to address float
6.25
2 tCLCL –55
1.5 tCLCL –55
0
ns
70
38.75
0
ns
162.5
0
ns
106.25
0
1.5 tCLCL +20
73.75
0
16.25
ns
ns
162.5
2.5 tCLCL –50
ns
ns
ns
ns
0
ns
46.25
ns
tWHLH
35, 36
External Clock
RD or WR high to ALE high
0.5 tCLCL –15
0.5 tCLCL +15
tCHCX
38
High time
0.4 tCLCL
tCLCL – tCLCX
ns
tCLCX
38
Low time
0.4 tCLCL
tCLCL – tCHCX
ns
tCLCH
38
Rise time
5
ns
tCHCL
38
Shift register
Fall time
5
ns
tXLXL
37
Serial port clock cycle time
6 tCLCL
375
ns
tQVXH
37
Output data setup to clock rising edge
5 tCLCL –25
287.5
ns
tXHQX
37
Output data hold after clock rising edge
tCLCL –15
47.5
ns
tXHDX
37
Input data hold after clock rising edge
0
tXHDV
37
Clock rising edge to input data valid6
0
5 tCLCL –133
ns
179.5
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 outputs = 80 pF
3. Interfacing the microcontroller to devices with float time up to 45ns is permitted. This limited bus contention will not cause damage to port 0
drivers.
4. Parts are guaranteed by design to operate down to 0 Hz.
5. Data shown in the table are the best mathematical models for the set of measured values obtained in tests. If a particular parameter
calculated at a customer specified frequency has a negative value, it should be considered equal to zero.
6. Below 16 MHz this parameter is 4 tCLCL – 133
2003 Jan 24
49
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
EXPLANATION OF THE AC SYMBOLS
P – PSEN
Q – Output data
R – RD signal
t – Time
V – Valid
W – WR signal
X – No longer a valid logic level
Z – Float
Examples: tAVLL = Time for address valid to ALE low.
tLLPL =Time for ALE low to PSEN low.
Each timing symbol has five characters. The first character is always
‘t’ (= time). The other characters, depending on their positions,
indicate the name of a signal or the logical status of that signal. The
designations are:
A – Address
C – Clock
D – Input data
H – Logic level high
I – Instruction (program memory contents)
L – Logic level low, or ALE
tLHLL
ALE
tAVLL
tLLPL
tPLPH
tLLIV
tPLIV
PSEN
tLLAX
INSTR IN
A0–A7
PORT 0
tPXIZ
tPLAZ
tPXIX
A0–A7
tAVIV
PORT 2
A0–A15
A8–A15
SU00006
Figure 34. 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 35. External Data Memory Read Cycle
2003 Jan 24
50
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
ALE
tWHLH
PSEN
tWLWH
tLLWL
WR
tLLAX
tAVLL
tWHQX
tQVWX
tQVWH
A0–A7
FROM RI OR DPL
PORT 0
DATA OUT
A0–A7 FROM PCL
INSTR IN
tAVWL
PORT 2
P2.0–P2.7 OR A8–A15 FROM DPF
A0–A15 FROM PCH
SU00026
Figure 36. 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 37. Shift Register Mode Timing
VCC–0.5
0.45V
0.7VCC
0.2VCC–0.1
tCHCL
tCHCX
tCLCH
tCLCX
tCLCL
SU00009
Figure 38. External Clock Drive
2003 Jan 24
51
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
VCC–0.5
VLOAD+0.1V
0.2VCC+0.9
0.2VCC–0.1
0.45V
VOH–0.1V
TIMING
REFERENCE
POINTS
VLOAD
VLOAD–0.1V
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’.
SU00717
SU00718
Figure 39. AC Testing Input/Output
Figure 40. Float Waveform
40
35
MAX ACTIVE MODE
ICCMAX = 1.1
FREQ. + 1.0
ICC(mA)
30
25
20
15
TYP ACTIVE MODE
10
MAX IDLE MODE
ICCMAX = 0.22
FREQ. + 1.0
5
TYP IDLE MODE
4
8
12
16
20
24
28
32
36
FREQ AT XTAL1 (MHz)
SU01684
Figure 41. ICC vs. FREQ for 12-clock operation
Valid only within frequency specifications of the specified operating voltage
2003 Jan 24
52
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
/*
##
as31 version V2.10
/ *js* /
##
##
##
source file: idd_ljmp1.asm
##
list file: idd_ljmp1.lst
created Fri Apr 20 15:51:40 2001
##
##########################################################
#0000
# AUXR equ 08Eh
#0000
# CKCON equ 08Fh
#
#
#0000
# org 0
#
# LJMP_LABEL:
0000 /75;/8E;/01;
#
MOV
AUXR,#001h
; turn off ALE
0003 /02;/FF;/FD;
#
LJMP
LJMP_LABEL
; jump to end of address space
0005 /00;
#
NOP
#
#FFFD
# org 0fffdh
#
# LJMP_LABEL:
#
FFFD /02;/FD;FF;
#
LJMP LJMP_LABEL
# ;
NOP
#
#
*/”
Figure 42. Source code used in measuring IDD operational
2003 Jan 24
53
SU01499
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
VCC
VCC
ICC
ICC
VCC
VCC
VCC
VCC
RST
RST
P0
P0
EA
EA
(NC)
XTAL2
(NC)
XTAL2
CLOCK SIGNAL
XTAL1
CLOCK SIGNAL
XTAL1
VSS
VSS
SU00719
SU00720
Figure 43. ICC Test Condition, Active Mode
All other pins are disconnected
VCC–0.5
Figure 44. 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 45. Clock Signal Waveform for ICC Tests in Active and Idle Modes
tCLCH = tCHCL = 5ns
VCC
ICC
VCC
VCC
RST
P0
EA
(NC)
XTAL2
XTAL1
VSS
SU00016
Figure 46. ICC Test Condition, Power Down Mode
All other pins are disconnected. VCC = 2 V to 5.5 V
2003 Jan 24
VCC
54
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
Program Verification
If security bits 2 and 3 have not been programmed, the on-chip
program memory can be read out for program verification. The
address of the program memory locations to be read is applied to
ports 1 and 2 as shown in Figure 49. The other pins are held at the
‘Verify Code Data’ levels indicated in Table 8. The contents of the
address location will be emitted on port 0. External pull-ups are
required on port 0 for this operation.
EPROM CHARACTERISTICS
All these devices can be programmed by using a modified Improved
Quick-Pulse Programming algorithm. It differs from older methods
in the value used for VPP (programming supply voltage) and in the
width and number of the ALE/PROG pulses.
The family contains two signature bytes that can be read and used
by an EPROM programming system to identify the device. The
signature bytes identify the device as being manufactured by
Philips.
If the 64 byte encryption table has been programmed, the data
presented at port 0 will be the exclusive NOR of the program byte
with one of the encryption bytes. The user will have to know the
encryption table contents in order to correctly decode the verification
data. The encryption table itself cannot be read out.
Table 8 shows the logic levels for reading the signature byte, and for
programming the program memory, the encryption table, and the
security bits. The circuit configuration and waveforms for quick-pulse
programming are shown in Figures 47 and 48. Figure 49 shows the
circuit configuration for normal program memory verification.
Reading the Signature Bytes
The signature bytes are read by the same procedure as a normal
verification of locations 030H and 031H, except that P3.6 and P3.7
need to be pulled to a logic low. The values are:
(030H) = 15H indicates manufactured by Philips
(031H) = CAH indicates 87C51RA2
CBH indicates 87C51RB2
CCH indicates 87C51RC2
CDH indicates 87C51RD2
(060H) = NA
Quick-Pulse Programming
The setup for microcontroller quick-pulse programming is shown in
Figure 47. Note that the device is running with a 4 to 6MHz
oscillator. The reason the oscillator needs to be running is that the
device is executing internal address and program data transfers.
The address of the EPROM location to be programmed is applied to
ports 1 and 2, as shown in Figure 47. The code byte to be
programmed into that location is applied to port 0. RST, PSEN and
pins of ports 2 and 3 specified in Table 8 are held at the ‘Program
Code Data’ levels indicated in Table 8. The ALE/PROG is pulsed
low 5 times as shown in Figure 48.
Program/Verify Algorithms
Any algorithm in agreement with the conditions listed in Table 8, and
which satisfies the timing specifications, is suitable.
To program the encryption table, repeat the 5 pulse programming
sequence for addresses 0 through 1FH, using the ‘Pgm Encryption
Table’ levels. Do not forget that after the encryption table is
programmed, verification cycles will produce only encrypted data.
Security Bits
With none of the security bits programmed the code in the program
memory can be verified. If the encryption table is programmed, the
code will be encrypted when verified. When only security bit 1 (see
Table 9) is programmed, MOVC instructions executed from external
program memory are disabled from fetching code bytes from the
internal memory, EA is latched on Reset and all further programming
of the EPROM is disabled. When security bits 1 and 2 are
programmed, in addition to the above, verify mode is disabled.
When all three security bits are programmed, all of the conditions
above apply and all external program memory execution is disabled.
To program the security bits, repeat the 5 pulse programming
sequence using the ‘Pgm Security Bit’ levels. After one security bit is
programmed, further programming of the code memory and
encryption table is disabled. However, the other security bits can still
be programmed.
Note that the EA/VPP pin must not be allowed to go above the
maximum specified VPP level for any amount of time. Even a narrow
glitch above that voltage can cause permanent damage to the
device. The VPP source should be well regulated and free of glitches
and overshoot.
Encryption Array
64 bytes of encryption array are initially unprogrammed (all 1s).
Trademark phrase of Intel Corporation.
2003 Jan 24
P87C51RA2/RB2/RC2/RD2
55
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
Table 8. EPROM Programming Modes
RST
PSEN
ALE/PROG
EA/VPP
P2.7
P2.6
P3.7
P3.6
P3.3
Read signature
MODE
1
0
1
1
0
0
0
0
X
Program code data
1
0
0*
VPP
1
0
1
1
X
Verify code data
1
0
1
1
0
0
1
1
X
Pgm encryption table
1
0
0*
VPP
1
0
1
0
X
Pgm security bit 1
1
0
0*
VPP
1
1
1
1
X
Pgm security bit 2
1
0
0*
VPP
1
1
0
0
X
Pgm security bit 3
1
0
0*
VPP
0
1
0
1
X
Program to 6-clock mode
1
0
0*
VPP
0
0
1
0
0
Verify 6-clock4
1
0
1
1
e
0
0
1
1
Verify security bits5
1
0
1
1
e
0
1
0
X
NOTES:
1. ‘0’ = Valid low for that pin, ‘1’ = valid high for that pin.
2. VPP = 12.75 V ±0.25 V.
3. VCC = 5 V±10% during programming and verification.
4. Bit is output on P0.4 (1 = 12x, 0 = 6x).
5. Security bit one is output on P0.7.
Security bit two is output on P0.6.
Security bit three is output on P0.3.
* ALE/PROG receives 5 programming pulses for code data (also for user array; 5 pulses for encryption or security bits) while VPP is held at
12.75 V. Each programming pulse is low for 100 µs (±10 µs) and high for a minimum of 10 µs.
Table 9. Program Security Bits for EPROM Devices
PROGRAM LOCK BITS1, 2
SB1
SB2
SB3
PROTECTION DESCRIPTION
1
U
U
U
No Program Security features enabled. (Code verify will still be encrypted by the Encryption Array if
programmed.)
2
P
U
U
MOVC instructions executed from external program memory are disabled from fetching code bytes
from internal memory, EA is sampled and latched on Reset, and further programming of the EPROM
is disabled.
3
P
P
U
Same as 2, also verify is disabled.
4
P
P
P
Same as 3, external execution is disabled. Internal data RAM is not accessible.
NOTES:
1. P – programmed. U – unprogrammed.
2. Any other combination of the security bits is not defined.
2003 Jan 24
56
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
+5V
A0–A7
VCC
P1
P0
1
RST
1
P3.6
EA/VPP
1
P3.7
ALE/PROG
OTP
XTAL2
4–6MHz
XTAL1
PGM DATA
+12.75V
5 PULSES TO GROUND
PSEN
0
P2.7
1
P2.6
0
A8–A13
P2.0–P2.5
VSS
A8–A15 are programming addresses
(not external memory addresses per
device pin out)
P3.4
A14
P3.5
A15 (RD2 ONLY)
SU01659
Figure 47. Programming Configuration
5 PULSES
1
ALE/PROG:
0
1
2
3
4
5
SEE EXPLODED VIEW BELOW
tGHGL = 10µs MIN
tGLGH = 100µs±10µs
1
ALE/PROG:
1
0
SU00875
Figure 48. PROG Waveform
+5V
VCC
A0–A7
P0
P1
1
RST
1
P3.6
1
P3.7
OTP
XTAL2
4–6MHz
XTAL1
EA/VPP
1
ALE/PROG
1
PSEN
0
P2.7
0 ENABLE
P2.6
0
P2.0–P2.5
VSS
P3.4
A8–A15 are programming addresses
(not external memory addresses per
device pin out)
P3.5
A8–A13
A14
A15 (RD2 ONLY)
SU01660
Figure 49. Program Verification
2003 Jan 24
PGM DATA
57
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
EPROM PROGRAMMING AND VERIFICATION CHARACTERISTICS
Tamb = 21°C to +27°C, VCC = 5V±10%, VSS = 0V (See Figure 50)
SYMBOL
VPP
PARAMETER
Programming supply voltage
MIN
MAX
UNIT
12.5
13.0
V
50
1
IPP
Programming supply current
1/tCLCL
Oscillator frequency
tAVGL
Address setup to PROG low
48tCLCL
tGHAX
Address hold after PROG
48tCLCL
tDVGL
Data setup to PROG low
48tCLCL
tGHDX
Data hold after PROG
48tCLCL
tEHSH
P2.7 (ENABLE) high to VPP
48tCLCL
tSHGL
VPP setup to PROG low
10
µs
tGHSL
VPP hold after PROG
10
µs
tGLGH
PROG width
90
tAVQV
Address to data valid
48tCLCL
tELQZ
ENABLE low to data valid
48tCLCL
tEHQZ
Data float after ENABLE
0
tGHGL
PROG high to PROG low
10
4
6
110
mA
MHz
µs
48tCLCL
µs
NOTE:
1. Not tested.
PROGRAMMING*
VERIFICATION*
P1.0–P1.7
P2.0–P2.5
P3.4
(A0 – A14)
ADDRESS
ADDRESS
PORT 0
P0.0 – P0.7
(D0 – D7)
DATA IN
tAVQV
DATA OUT
tDVGL
tAVGL
tGHDX
tGHAX
ALE/PROG
tGLGH
tSHGL
tGHGL
tGHSL
LOGIC 1
LOGIC 1
EA/VPP
LOGIC 0
tEHSH
tELQV
tEHQZ
P2.7
**
SU00871
NOTES:
* FOR PROGRAMMING CONFIGURATION SEE FIGURE 47.
FOR VERIFICATION CONDITIONS SEE FIGURE 49.
**
SEE TABLE 8.
Figure 50. EPROM Programming and Verification
2003 Jan 24
58
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
MASK ROM DEVICES
from the internal memory, EA is latched on Reset and all further
programming of the EPROM is disabled. When security bits 1 and 2
are programmed, in addition to the above, verify mode is disabled.
Security Bits
With none of the security bits programmed the code in the program
memory can be verified. If the encryption table is programmed, the
code will be encrypted when verified. When only security bit 1 (see
Table 10) is programmed, MOVC instructions executed from
external program memory are disabled from fetching code bytes
Encryption Array
64 bytes of encryption array are initially unprogrammed (all 1s).
Table 10. Program Security Bits
PROGRAM LOCK BITS1, 2
SB1
SB2
PROTECTION DESCRIPTION
1
U
U
No Program Security features enabled.
(Code verify will still be encrypted by the Encryption Array if programmed.)
2
P
U
MOVC instructions executed from external program memory are disabled from fetching code bytes from
internal memory, EA is sampled and latched on Reset, and further programming of the EPROM is disabled.
NOTES:
1. P – programmed. U – unprogrammed.
2. Any other combination of the security bits is not defined.
ROM CODE SUBMISSION FOR 8K ROM DEVICES (87C51RA2)
When submitting ROM code for the 8k ROM devices, the following must be specified:
1. 8 kbyte user ROM data
2. 64 byte ROM encryption key
3. ROM security bits.
ADDRESS
CONTENT
BIT(S)
COMMENT
0000H to 1FFFH
DATA
7:0
User ROM Data
2000H to 203FH
KEY
7:0
ROM Encryption Key
FFH = no encryption
2040H
SEC
0
ROM Security Bit 1
0 = enable security
1 = disable security
2040H
SEC
1
ROM Security Bit 2
0 = enable security
1 = disable security
Security Bit 1: When programmed, this bit has two effects on masked ROM parts:
1. External MOVC is disabled, and
2. EA is latched on Reset.
Security Bit 2: When programmed, this bit inhibits Verify User ROM.
NOTE: Security Bit 2 cannot be enabled unless Security Bit 1 is enabled.
If the ROM Code file does not include the options, the following information must be included with the ROM code.
For each of the following, check the appropriate box, and send to Philips along with the code:
Security Bit #1:
V
Enabled
V
Disabled
Security Bit #2:
V
Enabled
V
Disabled
Encryption:
V
No
V
Yes
2003 Jan 24
If Yes, must send key file.
59
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
ROM CODE SUBMISSION FOR 16K ROM DEVICES (87C51RB2)
When submitting ROM code for the 16K ROM devices, the following must be specified:
1. 16 kbyte user ROM data
2. 64 byte ROM encryption key
3. ROM security bits.
ADDRESS
CONTENT
BIT(S)
COMMENT
0000H to 3FFFH
DATA
7:0
User ROM Data
4000H to 403FH
KEY
7:0
ROM Encryption Key
FFH = no encryption
4040H
SEC
0
ROM Security Bit 1
0 = enable security
1 = disable security
4040H
SEC
1
ROM Security Bit 2
0 = enable security
1 = disable security
Security Bit 1: When programmed, this bit has two effects on masked ROM parts:
1. External MOVC is disabled, and
2. EA is latched on Reset.
Security Bit 2: When programmed, this bit inhibits Verify User ROM.
NOTE: Security Bit 2 cannot be enabled unless Security Bit 1 is enabled.
If the ROM Code file does not include the options, the following information must be included with the ROM code.
For each of the following, check the appropriate box, and send to Philips along with the code:
Security Bit #1:
V
Enabled
V
Disabled
Security Bit #2:
V
Enabled
V
Disabled
Encryption:
V
No
V
Yes
2003 Jan 24
If Yes, must send key file.
60
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
ROM CODE SUBMISSION FOR 32K ROM DEVICES (87C51RC2)
When submitting ROM code for the 32K ROM devices, the following must be specified:
1. 32 kbyte user ROM data
2. 64 byte ROM encryption key
3. ROM security bits.
ADDRESS
CONTENT
BIT(S)
COMMENT
0000H to 7FFFH
DATA
7:0
User ROM Data
8000H to 803FH
KEY
7:0
ROM Encryption Key
FFH = no encryption
8040H
SEC
0
ROM Security Bit 1
0 = enable security
1 = disable security
8040H
SEC
1
ROM Security Bit 2
0 = enable security
1 = disable security
Security Bit 1: When programmed, this bit has two effects on masked ROM parts:
1. External MOVC is disabled, and
2. EA is latched on Reset.
Security Bit 2: When programmed, this bit inhibits Verify User ROM.
NOTE: Security Bit 2 cannot be enabled unless Security Bit 1 is enabled.
If the ROM Code file does not include the options, the following information must be included with the ROM code.
For each of the following, check the appropriate box, and send to Philips along with the code:
Security Bit #1:
V
Enabled
V
Disabled
Security Bit #2:
V
Enabled
V
Disabled
Encryption:
V
No
V
Yes
2003 Jan 24
If Yes, must send key file.
61
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
ROM CODE SUBMISSION FOR 64K ROM DEVICE (87C51RD2)
When submitting ROM code for the 64K ROM devices, the following must be specified:
1. 64 kbyte user ROM data
2. 64 byte ROM encryption key
3. ROM security bits.
ADDRESS
CONTENT
BIT(S)
COMMENT
0000H to FFFFH
DATA
7:0
User ROM Data
10000H to 1003FH
KEY
7:0
ROM Encryption Key
FFH = no encryption
10040H
SEC
0
ROM Security Bit 1
0 = enable security
1 = disable security
10040H
SEC
1
ROM Security Bit 2
0 = enable security
1 = disable security
Security Bit 1: When programmed, this bit has two effects on masked ROM parts:
1. External MOVC is disabled, and
2. EA is latched on Reset.
Security Bit 2: When programmed, this bit inhibits Verify User ROM.
NOTE: Security Bit 2 cannot be enabled unless Security Bit 1 is enabled.
If the ROM Code file does not include the options, the following information must be included with the ROM code.
For each of the following, check the appropriate box, and send to Philips along with the code:
Security Bit #1:
V
Enabled
V
Disabled
Security Bit #2:
V
Enabled
V
Disabled
Encryption:
V
No
V
Yes
2003 Jan 24
If Yes, must send
62
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
DIP40: plastic dual in-line package; 40 leads (600 mil)
2003 Jan 24
63
P87C51RA2/RB2/RC2/RD2
SOT129-1
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
PLCC44: plastic leaded chip carrier; 44 leads
2003 Jan 24
P87C51RA2/RB2/RC2/RD2
SOT187-2
64
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
LQFP44: plastic low profile quad flat package; 44 leads; body 10 x 10 x 1.4 mm
2003 Jan 24
65
SOT389-1
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
P87C51RA2/RB2/RC2/RD2
REVISION HISTORY
Rev
Date
Description
_3
20030124
Product data (9397 750 10994); ECN 853-2391 29335 dated 07 Jan 2003.
Modifications:
• Updated ordering information table.
_2
2003 Jan 24
20021028
Product data (9397 750 10393); ECN 853-2391 29117 dated 28 Oct 2002.
66
Philips Semiconductors
Product data
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
P87C51RA2/RB2/RC2/RD2
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
Data sheet status
Level
Data sheet status [1]
Product
status [2] [3]
Definitions
I
Objective data
Development
This data sheet contains data from the objective specification for product development.
Philips Semiconductors reserves the right to change the specification in any manner without notice.
II
Preliminary data
Qualification
This data sheet contains data from the preliminary specification. Supplementary data will be published
at a later date. Philips Semiconductors reserves the right to change the specification without notice, in
order to improve the design and supply the best possible product.
III
Product data
Production
This data sheet contains data from the product specification. Philips Semiconductors reserves the
right to make changes at any time in order to improve the design, manufacturing and supply. Relevant
changes will be communicated via a Customer Product/Process Change Notification (CPCN).
[1] Please consult the most recently issued data sheet before initiating or completing a design.
[2] The product status of the device(s) described in this data sheet may have changed since this data sheet was published. The latest information is available on the Internet at URL
http://www.semiconductors.philips.com.
[3] For data sheets describing multiple type numbers, the highest-level product status determines the data sheet status.
Definitions
Short-form specification — The data in a short-form specification is extracted from a full data sheet with the same type number and title. For detailed information see
the relevant data sheet or data handbook.
Limiting values definition — Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 60134). Stress above one or more of the limiting
values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or at any other conditions above those given
in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended periods may affect device reliability.
Application information — Applications that are described herein for any of these products are for illustrative purposes only. Philips Semiconductors make no
representation or warranty that such applications will be suitable for the specified use without further testing or modification.
Disclaimers
Life support — These products are not designed for use in life support appliances, devices, or systems where malfunction of these products can reasonably be
expected to result in personal injury. Philips Semiconductors customers using or selling these products for use in such applications do so at their own risk and agree
to fully indemnify Philips Semiconductors for any damages resulting from such application.
Right to make changes — Philips Semiconductors reserves the right to make changes in the products—including circuits, standard cells, and/or software—described
or contained herein in order to improve design and/or performance. When the product is in full production (status ‘Production’), relevant changes will be communicated
via a Customer Product/Process Change Notification (CPCN). Philips Semiconductors assumes no responsibility or liability for the use of any of these products, conveys
no license or title under any patent, copyright, or mask work right to these products, and makes no representations or warranties that these products are free from patent,
copyright, or mask work right infringement, unless otherwise specified.
 Koninklijke Philips Electronics N.V. 2003
All rights reserved. Printed in U.S.A.
Contact information
For additional information please visit
http://www.semiconductors.philips.com.
Fax: +31 40 27 24825
Date of release: 01-03
For sales offices addresses send e-mail to:
[email protected].
Document order number:
2003 Jan 24
67
9397 750 10994