Table of Contents
Advertisement
-
M 7-3500
76.
I/O port map
8255 ON SUBCPU BUS
I N
OUT
# 3 X
8255
Chip address(0011/xxxx]
Group A: Mode 1
Group B: Mode 0
O
O
o
c
TJ
W
I'A7
I'A6
I'A5
PA4
PAS
PA2
PA1
PAO
PC7
PC6
ACK inputi
PCS
PC4
PCS
PC 2
PCI
PCO
PB7
PB6
PB5
PB4
PB3
PB2
PB1
PBO
Output
OBF Output
INTR
Output
DATA8
I) ATA 7
DAT A 6
DATA5
DATA 4
DAT A 3
DATA2
D ATA l
ACK T-S ET
ACK
STROBE
J
MUS IC, sustain
NOT USE
ACKC
STC
DC
P / M
SRDY
CLK
Printer
Din
C2
C l
CO
STRB
Keyboard
CG seleclion
Sub CPU R E A D Y
Clock
INPUT PORTC 7 4 L S 2 4 4
7 4 L S 2 4 4
port address[0100/xxxx]
IN
OUT
#4X
CDS73
CDS6D
CDS5D
CDS3D
CDS2D
CDS1
C D S O D
HLT KEY
STK
-i
DK
J
PDTR
PE
BUSY
Reads the 8255 OBF (PC7)
Output or timer Output.
Keyboard
Printer
- 80-
Advertisement
Table of Contents
