ACPA Expansion Bus Pinout

Pin Signal Definition Dir Pin Signal Definition Dir
1 CLKIN Input INT OSC [40MHz] I 31 +12 Vdc ??? (via 10 Ω R)
2 -RS Reset input I 32 READY Data ready input I
3 N/C 33 -INT2/0 External user interrupt input I
4 Vss Ground I 34 Vss Ground I
5 Vcc +5V dc I 35 -HOLD Hold input [idle mode] I
6 CLKX CLK serial port xmit output I 36 CLKR CLK for serial port recv input I
7 D15 Data bus D15 [M] [MSB] I/O/Z 37 D14 Data bus D14 [M] I/O/Z
8 D13 Data bus D13 [M] I/O/Z 38 D12 Data bus D12 [M] I/O/Z
9 D11 Data bus D11 [M] I/O/Z 39 D10 Data bus D10 [M] I/O/Z
10 D9 Data bus D9 [M] I/O/Z 40 D8 Data bus D8 [M] I/O/Z
11 D7 Data bus D7 [M] I/O/Z 41 D6 Data bus D6 [M] I/O/Z
12 D5 Data bus D5 [M] I/O/Z 42 D4 Data bus D4 [M] I/O/Z
13 D3 Data bus D3 [M] I/O/Z 43 D2 Data bus D2 [M] I/O/Z
14 D1 Data bus D1 [M] I/O/Z 44 D0 Data bus D0 [M] [LSB] I/O/Z
15 DR Serial data receive input I 45 DX Serial data transmit output O/Z
16 Vss Ground I 46 -HOLDA Hold acknowledge signal O
17 Vcc +5 Vdc I 47 Vss Ground I
18 -STRB Strobe signal O/Z 48 FSX Frame synch pulse for xmit. I/O/Z
19 -PS Program select signal O/Z 49 R/-W Read/write signal O/Z
20 -IS I/O space select signal O/Z 50 FSR Frame synch pulse for recv input I
21 A0 Address bus A0 [LSB] O/Z 51 -DS Data select signal O/Z
22 A2 Address bus A2 O/Z 52 A1 Address bus A1 O/Z
23 A4 Address bus A4 O/Z 53 A3 Address bus A3 O/Z
24 A6 Address bus A6 O/Z 54 A5 Address bus A5 O/Z
25 A8 Address bus A8 O/Z 55 A7 Address bus A7 O/Z
26 A10 Address bus A10 O/Z 56 A9 Address bus A9 O/Z
27 A12 Address bus A12 O/Z 57 A11 Address bus A11 O/Z
28 A14 Address bus A14 O/Z 58 A13 Address bus A13 O/Z
29 Vcc +5 Vdc I 59 A15 Address bus A15 [MSB] O/Z
30 Vss Ground I 60 Vss Ground I

All Data Bus and Address Bus lines are 16-bit.
All Data Bus Lines are Multiplexed between program, data, and I/O spaces
PS, DS, IS select the Program, data, and I/O space used by Data Bus and Address Bus
I/O/Z denotes input/output/high-impedance state.

Content created and/or collected by:
Louis F. Ohland, Peter H. Wendt, David L. Beem, William R. Walsh, Tatsuo Sunagawa, Tomáš Slavotínek, Jim Shorney, Tim N. Clarke, Kevin Bowling, and many others.

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Last update: 20 Jan 2024 - Changelog | About | Legal & Contact