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