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IC89C54 Datasheet, PDF (6/24 Pages) Integrated Circuit Solution Inc – CMOS SINGLE CHIP 8-BIT MICROCONTROLLER with 16/32/64-Kbytes of FLASH
IC89C54/58/64
Table 1. Detailed Pin Description (continued)
Symbol PDIP
P3.0-P3.7 10-17
PLCC
11, 13-19
PQFP I/O
5, 7-13 I/O
10
11
11
13
12
14
13
15
5
I
7
O
8
I
9
I
14
16
10
I
15
17
11
I
16
18
12
O
17
19
13
O
PSEN
29
32
26
O
RST
9
10
4
I
XTAL 1
19
21
15
I
XTAL 2
18
20
14
O
GND
20
22
16
I
Vcc
40
44
38
I
Name and Function
Port 3: Port 3 is an 8-bit bi-directional 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 pulled low will source current because
of the internal pullups.
Port 3 also serves the special features, as listed below:
RxD (P3.0): Serial input port.
TxD (P3.1): Serial output port.
INT0 (P3.2): External interrupt. Serve as A14 during memory
program and verification.
INT1 (P3.3): External interrupt. Serve as A15 during memory
program and verification.
T0 (P3.4): Timer 0 external input.
T1 (P3.5): Timer 1 external input.
WR (P3.6):External data memory write strobe. Control signal
during memory program, verification and erase.
RD (P3.7): External data memory read strobe. Control signal
during memory program, verification and erase.
Program Store Enable: The read strobe to external program
memory. When the device is 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.PSEN is an input control
signal while memory program and verification.
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.
A small internal resistor permits power-on reset using only a
capacitor connected to VCC.
RST is an input control signal during memory program and
verification.
Crystal 1: Input to the inverting oscillator amplifier and input
to the internal clock generator circuits.
Crystal 2: Output from the inverting oscillator amplifier.
Ground: 0V reference.
Power Supply: This is the power supply voltage for operation.
6
Integrated Circuit Solution Inc.
MC009-0B