P89C668 Philips Semiconductors, P89C668 Datasheet - Page 5

• Manufacturer Part Number: P89C668
• Description: 80C51 8-bit Flash microcontroller family 64KB ISP FLASH with 8KB RAM
• Manufacturer: Philips Semiconductors

Philips Semiconductors
PIN DESCRIPTIONS
2001 Jul 27
V
V
P0.0–0.7
P1.0–P1.7
P2.0–P2.7
P3.0–P3.7
RST
ALE
PSEN
MNEMONIC
MNEMONIC
SS
CC
80C51 8-bit Flash microcontroller family
64KB ISP Flash with 8KB RAM
PLCC
43–36
24–31
13–19
2–9
PIN NUMBER
11,
22
44
11
13
14
15
16
17
18
19
10
33
32
2
3
4
5
6
7
8
9
5, 7–13
40–44,
LQFP
37–30
18–25
1–3
16
38
40
41
42
43
44
10
12
13
27
26
11
1
2
3
5
7
8
9
4
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
O
O
O
O
O
I
I
I
I
I
I
I
I
I
I
to them are pulled high by the internal pull-ups and can be used as inputs. As inputs, port 3 pins that
Reset: A high on this pin for two machine cycles while the oscillator is running, resets the device. An
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 and data memory. In this application, it uses strong
internal pull-ups when emitting 1s.
Port 1: Port 1 is an 8-bit bidirectional I/O port with internal pull-ups on all pins except P1.6 and
P1.7 which are open drain. 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 P89C668 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
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
are externally being pulled low will source current because of the pull-ups. (See DC Electrical
Characteristics: I
internal diffused resistor 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 at a constant rate of 1/6 the oscillator
frequency, and can be used for external timing or clocking. Note that one ALE pulse is skipped
during each access to external data memory. ALE can be disabled by setting SFR auxiliary.0.
With this bit set, ALE will be active only during a MOVX instruction.
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.
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
SCL (P1.6): I
SDA (P1.7): I
RxD (P3.0): Serial input port
TxD (P3.1): Serial output port
INT0 (P3.2): External interrupt
INT1 (P3.3): External interrupt
CEX3/T0 (P3.4): Timer 0 external input; Capture/Compare External I/O for PCA module 3
CEX4/T1 (P3.5): Timer 1 external input; Capture/Compare External I/O for PCA module 4
WR (P3.6): External data memory write strobe
RD (P3.7): External data memory read strobe
IL
2
2
C bus clock line (open drain)
C bus data line (open drain)
). Port 3 also serves the special features of the P89C668, as listed below:
5
SS
IL
permits a power-on reset using only an external capacitor to V
). Port 2 emits the high-order address byte during fetches from
NAME AND FUNCTION
NAME AND FUNCTION
IL
P89C668
).
Preliminary data
CC
.