Service manual

MZ-800
3-6. Colour plotter printer control LSI
Pin assignment
Symbol
Name
In/out
Function
Vss
Ground
Connected to OY.
Vcc
Main power
Connected to 5Y.
Voo
Power
Connected to 5Y.
PROG
Program
I
Out
Not used.
Plo ~P17
Port I
Used as printer control signals.
P2
0
~ P27
I
Port 2
Used for data input port from CPU.
Do - D7
1
Data bus
Used for stepper motor control signals.
I
To
Test pin 0
In Input from pen change switch.
Tl
1
Test pin 1
In
I
Input from paper feed switch.
INT
i
Interrupt input
In Data transfer strobe MZ- 700 ... MZ 1 PO 1.
I
RD
I
i
Read signal
In
Not used.
-
I
Write signal
I
Out
Not used.
WR
i
I
RESET
!
Reset
In
Used to initialize the processor.
ALE
1
Address latch enable Out
I
Not used.
I
I
I
PSEN
I
Program store enable
Out
I
Not used.
SS
I
Single step
In Not used.
EA
External access
In Active when EA
= OY.
Pins used to attach the crystal oscillatQr or RC network to
Xl, Xl
Crystal inputs
In
generate internal clock. However, external clock signal may be
inputted through these pins.
40