Specifications

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Table 2-18B. AT Expansion Bus Connector, B1-B32 (J9)
PIN SIGNAL NAME FUNCTION IN/OUT
B1 GND Ground ---
B2 RESET System reset signal out
B3 +5V +5 volts power ---
B4 IRQ9 Interrupt request 9 in
B5 -5V To J4 pin 9 ---
B6 DRQ2 DMA request 2 in
B7 -12V To J4 pin 10 ---
B8 -0WS Zero wait state in
B9 +12V To J4 pin 8 ---
B10 GND Ground ---
B11 -SMEMW Memory Write (lower 1MB) i/o
B12 -SMEMR Memory Read (lower 1MB) i/o
B13 -IOW I/O Write i/o
B14 -IOR I/O Read i/o
B15 -DACK3 DMA Acknowledge 3 in
B16 DRQ3 DMA Request 3 out
B17 -DACK1 DMA Acknowledge 1 out
B18 DRQ1 DMA Request 1 in
B19 -REFRESH Memory Refresh i/o
B20 CLK CPU clock (e.g. 12MHz) out
B21 IRQ7 Interrupt Request 7 in
B22 IRQ6 Interrupt Request 6 in
B23 IRQ5 Interrupt Request 5 in
B24 IRQ4 Interrupt Request 4 in
B25 IRQ3 Interrupt Request 3 in
B26 -DACK2 DMA Acknowledge 2 out
B27 T/C DMA Terminal Count out
B28 BALE Address latch enable out
B29 +5V +5 volts power ---
B30 OSC 14.3 MHz clock out
B31 GND Ground out
B32 GND (*) Ground out
(*) Note: B32 is an added ground. It can be left unconnected when
using standard backplanes or cards.