W78C32C
PSEN
Program Store Enable Output, active low.
PSEN
enables the external ROM onto the Port 0
address/data bus during fetch and MOVC operations.
PSEN
goes to a high state during reset with a
weak pull-up.
XTAL1
Crystal 1. This is the crystal oscillator input. This pin may be driven by an external clock.
XTAL2
Crystal 2. This is the crystal oscillator output. It is the inversion of XTAL1.
V
SS
, V
CC
Power Supplies. These are the chip ground and positive supplies.
BLOCK DIAGRAM
RAM
256
Bytes
SFR
Port 0
Port 1
Alternate
Timer 2
Port 2
Data Bus
Port 3
Alternate
Serial
Port
Timer 0
Interrupt
Timer 1
INT 0
INT 1
CPU
CORE
-4-
WINBOND [ WINBOND ]
