P87C51RB2 PHILIPS [NXP Semiconductors], P87C51RB2 Datasheet - Page 7

• Manufacturer Part Number: P87C51RB2
• Description: 80C51 8-bit microcontroller family
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
PIN DESCRIPTIONS
2003 Jan 24
V
V
P0.0–0.7
P1.0–P1.7
P2.0–P2.7
P3.0–P3.7
RST
ALE
MNEMONIC
MNEMONIC
SS
CC
80C51 8-bit microcontroller family
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
39–32
21–28
10–17
PDIP
1–8
20
40
10
12
13
14
15
16
17
30
11
1
2
3
4
5
6
7
8
9
PIN NUMBER
PLCC
43–36
24–31
13–19
2–9
11,
22
44
11
13
14
15
16
17
18
19
10
33
2
3
4
5
6
7
8
9
5, 7–13
40–44,
37–30
18–25
LQFP
1–3
16
38
40
41
42
43
44
10
11
12
13
27
1
2
3
5
7
8
9
4
8KB/16KB/32KB/64KB OTP
TYPE
TYPE
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
O
O
O
O
I
I
I
I
I
I
I
I
I
I
and data memory. In this application, it uses strong internal pull-ups when emitting 1s.
Ground: 0 V reference.
Power Supply: This is the power supply voltage for normal, idle, and power-down
operation.
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
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:
I
Alternate functions for P87C51RA2/RB2/RC2/RD2 Port 1 include:
Port 2: Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. Port 2 pins that
have 1s written to them are pulled high by the internal pull-ups and can be used as
inputs. As inputs, port 2 pins that are externally being pulled low will source current
because of the internal pull-ups. (See DC Electrical Characteristics: I
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.
Port 3: Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. Port 3 pins that
have 1s written to them are pulled high by the internal pull-ups and can be used as
inputs. As inputs, port 3 pins that are externally being pulled low will source current
because of the pull-ups. (See DC Electrical Characteristics: I
the special features of the P87C51RA2/RB2/RC2/RD2, as listed below:
Reset: A high on this pin for two machine cycles while the oscillator is running,
resets the device. An internal resistor to V
an external capacitor to V
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.
IL
).
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
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
7
CC
.
NAME AND FUNCTION
NAME AND FUNCTION
P87C51RA2/RB2/RC2/RD2
SS
permits a power-on reset using only
IL
). Port 3 also serves
IL
). Port 2
Product data