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ISA Bus Pinouts
ISA - Industry Standard Architecture. Most computers had ISA slots, but nowadays it is mostly replaced by PCI.
The ISA bus protocol is quite simple. ISA supports 8 bit mode as well as 16 bit mode.
If you have a look at a 16-bit ethernet card you'll see that it's connectors are split into two groups.
The smaller one is only used in 16-bit mode - normally, the NIC looks on power up if the second group is connected and chooses thereupon the operation mode.
Every ISA card is configured for a base address and an IRQ line. These two parameters make it possible to have more than one card on the ISA bus.
Here are the pinouts for the ISA Bus. The "Rear of Computer" means the back of the computer. Ex:
If you had a 8 bit modem, it would be the side you would plug the phone cord into with the card in the slot.
ISA Bus (8-bit) Pinouts
Rear of Computer/Looking from the top
:------:------:
GROUND |- B1 A1 -| I/O CH CHK
RESET DRV |- B2 A2 -| DATA 7
+5VDC |- B3 A3 -| DATA 6
IRQ 9 |- B4 A4 -| DATA 5
-5VDC |- B5 A5 -| DATA 4
DRQ 2 |- B6 A6 -| DATA 3
-12VDC |- B7 A7 -| DATA 2
-0 WAIT |- B8 A8 -| DATA 1
+12VDC |- B9 A9 -| DATA 0
GROUND |- B10 A10 -| -I/O RDY
-SMEMW |- B11 A11 -| AEN
-SMEMR |- B12 A12 -| ADDR 19
-IOW |- B13 A13 -| ADDR 18
-IOR |- B14 A14 -| ADDR 17
-DACK 3 |- B15 A15 -| ADDR 16
DRQ 3 |- B16 A16 -| ADDR 15
-DACK 1 |- B17 A17 -| ADDR 14
DRQ 1 |- B18 A18 -| ADDR 13
-REFRESH |- B19 A19 -| ADDR 12
CLK (4.77MHz) |- B20 A20 -| ADDR 11
IRQ 7 |- B21 A21 -| ADDR 10
IRQ 6 |- B22 A22 -| ADDR 9
IRQ 5 |- B23 A23 -| ADDR 8
IRQ 4 |- B24 A24 -| ADDR 7
IRQ 3 |- B25 A25 -| ADDR 6
-DACK 2 |- B26 A26 -| ADDR 5
T/C |- B27 A27 -| ADDR 4
BALE |- B28 A28 -| ADDR 3
+5VDC |- B29 A29 -| ADDR 2
OSC(14.3MHz) |- B30 A30 -| ADDR 1
GROUND |- B31 A31 -| ADDR 0
:------:------:
ISA Bus (16-bit) Pinouts
Rear of Computer/Looking from the top
:------:------:
GROUND |- B1 A1 -| I/O CH CHK
RESET DRV |- B2 A2 -| DATA 7
+5VDC |- B3 A3 -| DATA 6
IRQ 9 |- B4 A4 -| DATA 5
-5VDC |- B5 A5 -| DATA 4
DRQ 2 |- B6 A6 -| DATA 3
-12VDC |- B7 A7 -| DATA 2
-0 WAIT |- B8 A8 -| DATA 1
+12VDC |- B9 A9 -| DATA 0
GROUND |- B10 A10 -| -I/O RDY
-SMEMW |- B11 A11 -| AEN
-SMEMR |- B12 A12 -| ADDR 19
-IOW |- B13 A13 -| ADDR 18
-IOR |- B14 A14 -| ADDR 17
-DACK 3 |- B15 A15 -| ADDR 16
DRQ 3 |- B16 A16 -| ADDR 15
-DACK 1 |- B17 A17 -| ADDR 14
DRQ 1 |- B18 A18 -| ADDR 13
-REFRESH |- B19 A19 -| ADDR 12
CLK (8.33MHz) |- B20 A20 -| ADDR 11
IRQ 7 |- B21 A21 -| ADDR 10
IRQ 6 |- B22 A22 -| ADDR 9
IRQ 5 |- B23 A23 -| ADDR 8
IRQ 4 |- B24 A24 -| ADDR 7
IRQ 3 |- B25 A25 -| ADDR 6
-DACK 2 |- B26 A26 -| ADDR 5
T/C |- B27 A27 -| ADDR 4
BALE |- B28 A28 -| ADDR 3
+5VDC |- B29 A29 -| ADDR 2
OSC(14.3MHz) |- B30 A30 -| ADDR 1
GROUND |- B31 A31 -| ADDR 0
:------:------:
:------:------:
-MEM CS16 |- D1 C1 -| -SBHE
-I/O CS16 |- D2 C2 -| LADDR 23
IRQ 10 |- D3 C3 -| LADDR 22
IRQ 11 |- D4 C4 -| LADDR 21
IRQ 12 |- D5 C5 -| LADDR 20
IRQ 13 |- D6 C6 -| LADDR 19
IRQ 14 |- D7 C7 -| LADDR 18
-DACK 0 |- D8 C8 -| LADDR 17
DRQ 0 |- D9 C9 -| -MEMR
-DACK 5 |- D10 C10 -| -MEMW
DRQ 5 |- D11 C11 -| DATA 8
-DACK 6 |- D12 C12 -| DATA 9
DRQ 6 |- D13 C13 -| DATA 10
-DACK 7 |- D14 C14 -| DATA 11
DRQ 7 |- D15 C15 -| DATA 12
+5VDC |- D16 C16 -| DATA 13
-MASTER |- D17 C17 -| DATA 14
GROUND |- D18 C18 -| DATA 15
:------:------:
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