Product Reference2–67Table 2–47. AT Expansion Bus Connector, B1-B32 (P1)
Pin Signal
Name Function In/Out Current PU/PD/S *
B1
B2
B3
B4
B5
B6
B7
B8
B9
B10
B11
B12
B13
B14
B15
B16
B17
B18
B19
B20
B21
B22
B23
B24
B25
B26
B27
B28
B29
B30
B31
B32
GND
RESETDRV
+5V
IRQ9
-5V
DRQ2
-12V
ENDXFR*
+12V
Key
SMEMW*
SMEMR*
IOW
IOR
DACK3*
DRQ3
DACK1*
DRQ1
REFRESH*
SYSCLK
IRQ7
IRQ6
IRQ5
IRQ4
IRQ3
DACK2*
TC
BALE
+5V
OSC
GND
GND
Ground
System reset signal
+5 Volt power
Interrupt request 9
To J7-5
DMA request 2
To J7-6
Zero wait state
To J7-4
Key pin
Mem Write(l wr 1MB)
Mem Read(lwr 1MB)
I/O Write
I/O Read
DMA Acknowledge 3
DMA Request 3
DMA Acknowledge 1
DMA Request 1
Memory Refres h
Sys Clock
Interrupt Request 7
Interrupt Request 6
Interrupt Request 5
Interrupt Request 4
Interrupt Request 3
DMA Acknowledge 2
DMA Terminal Count
Address latch enable
+5V power
14.3 MHz clock
Ground
Ground
N/A
OUT
N/A
IN
N/A
IN
N/A
IN
N/A
N/A
I/O
I/O
I/O
I/O
OUT
IN
OUT
IN
I/O
OUT
IN
IN
IN
IN
IN
OUT
OUT
OUT
N/A
OUT
N/A
N/A
N/A
4 mA
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
4 mA
4 mA
4 mA
4 mA
6 mA
N/A
6 mA
N/A
4 mA
4 mA
N/A
N/A
N/A
N/A
N/A
6 mA
4 mA
4 mA
N/A
6 mA
N/A
N/A
27K PU
2.2K PD
22 S, 27K PU
22 S, 10K PU
22 S, 27K PU
22 S, 27K PU
2.2K PD
2.2K PD
22 S,1K PU
27K PU
27K PU
27K PU
10K PU
10K PU
33 S
* PU = pull up; PD = pull down; S = resistance in series. All values in ohms.