82C55A
MODE 2 AND MODE 0 (INPUT)
PC3
PA7-PA0
PC7
CONTROL WORD
D7 D6 D5 D4 D3 D2 D1 D0
1
1
0
1
1/0
PC6
PC4
PC5
PC2-PC0
RD
PB7-PB0
WR
8
WR
3
8
OBFA
ACKA
STBA
IBFA
I/O
RD
PB7, PB0
8
CONTROL WORD
D7 D6 D5 D4 D3 D2 D1 D0
1
1
0
0
1/0
INTRA
MODE 2 AND MODE 0 (OUTPUT)
PC3
PA7-PA0
PC7
PC6
PC4
PC5
PC2-PC0
3
8
OBFA
ACKA
STBA
IBFA
I/O
INTRA
PC2-PC0
1 = INPUT
0 = OUTPUT
PC2-PC0
1 = INPUT
0 = OUTPUT
MODE 2 AND MODE 1 (OUTPUT)
PC3
PA7-PA0
PC7
CONTROL WORD
D7 D6 D5 D4 D3 D2 D1 D0
1
1
1
0
PC6
PC4
PC5
PB7-PB0
PC1
RD
PC2
PC0
8
OBFB
ACKB
INTRB
8
OBFA
ACKA
STBA
IBFA
INTRA
MODE 2 AND MODE 1 (INPUT)
PC3
PA7-PA0
PC7
CONTROL WORD
D7 D6 D5 D4 D3 D2 D1 D0
1
1
1
1
PC6
PC4
PC5
PB7-PB0
PC2
RD
PC1
PC0
8
STBB
IBFB
INTRB
8
OBFA
ACKA
STBA
IBFA
INTRA
WR
WR
FIGURE 14. MODE 2 COMBINATIONS
12
HARRIS [ HARRIS CORPORATION ]
