W77C58 Datasheet, PDF (3/71 Pages) Winbond – 8 BIT MICROCONTROLLER

Preliminary W77C58
PIN DESCRIPTION
SYMBOL
EA
PSEN
ALE
RST
XTAL1
XTAL2
VSS
VDD
P0.0−P0.7
P1.0−P1.7
P2.0−P2.7
P3.0−P3.7
TYPE
DESCRIPTIONS
I EXTERNAL ACCESS ENABLE: This pin forces the processor to execute out of
external ROM. It should be kept high to access internal ROM. The ROM address and
data will not be present on the bus if EA pin is high and the program counter is within
32 KB area. Otherwise they will be present on the bus.
O _{PROGRAM STORE ENABLE: PSEN enables the external ROM data onto the Port}
0 address/data bus during fetch and MOVC operations.
O ADDRESS LATCH ENABLE: ALE is used to enable the address latch that separates
the address from the data on Port 0.
I RESET: A high on this pin for two machine cycles while the oscillator is running resets
the device.
I CRYSTAL1: This is the crystal oscillator input. This pin may be driven by an external
clock.
O CRYSTAL2: This is the crystal oscillator output. It is the inversion of XTAL1.
I GROUND: Ground potential
I POWER SUPPLY: Supply voltage for operation.
I/O PORT 0: Port 0 is an open-drain bi-directional I/O port. This port also provides a
multiplexed low order address/data bus during accesses to external memory.
I/O PORT 1: Port 1 is a bi-directional I/O port with internal pull-ups. The bits have
alternate functions which are described below:
T2(P1.0): Timer/Counter 2 external count input
T2EX(P1.1): Timer/Counter 2 Reload/Capture/Direction control
RXD1(P1.2): Serial port 1 RXD
TXD1(P1.3): Serial port 1 TXD
INT2(P1.4): External Interrupt 2
INT3 (P1.5): External Interrupt 3
INT4(P1.6): External Interrupt 4
INT5 (P1.7): External Interrupt 5
I/O PORT 2: Port 2 is a bi-directional I/O port with internal pull-ups. This port also provides
the upper address bits for accesses to external memory.
I/O PORT 3: Port 3 is a bi-directional I/O port with internal pull-ups. All bits have alternate
functions, which are described below:
RXD(P3.0) : Serial Port 0 input
TXD(P3.1) : Serial Port 0 output
INT0 (P3.2) : External Interrupt 0
INT1(P3.3) : External Interrupt 1
T0(P3.4) : Timer 0 External Input
T1(P3.5) : Timer 1 External Input
WR (P3.6) : External Data Memory Write Strobe
P4.0−P4.3
RD (P3.7) : External Data Memory Read Strobe
I/O PORT 4: Port 4 is a 4-bit bi-directional I/O port. The P4.0 also provides the alternate
function WAIT which is the wait state control signal.
* Note: TYPE I: input, O: output, I/O: bi-directional.
Publication Release Date: September 1999
-3-
Revision A1