Apple Macintosh Portable ROM Expansion pinout

#Computer#Memory cards

50 PIN UNKNOWN CONNECTOR

PinNameDescription
1+5V+5 VDC
2A1Address bit 1
3A2Address bit 2
4A3Address bit 3
5A4Address bit 4
6A5Address bit 5
7A6Address bit 6
8A7Address bit 7
9A8Address bit 8
10A9Address bit 9
11A10Address bit 10
12A11Address bit 11
13A12Address bit 12
14A13Address bit 13
15A14Address bit 14
16A15Address bit 15
17A16Address bit 16
18A17Address bit 17
19A18Address bit 18
20A19Address bit 19
21A20Address bit 20
22A21Address bit 21
23A22Address bit 22
24A23Address bit 23
25GNDGround
26GNDGround
27/DTACKData Transfer Acknowledge
28/ASAddress Strobe
29/ROM_CSROM Chip Select
3016M16 MHz Clock
31/EXT_DTACKExternal Data Transfer Acknowledge
32/DELAY_CS
33D0Data bit 0
34D1Data bit 1
35D2Data bit 2
36D3Data bit 3
37D4Data bit 4
38D5Data bit 5
39D6Data bit 6
40D7Data bit 7
41D8Data bit 8
42D9Data bit 9
43D10Data bit 10
44D11Data bit 11
45D12Data bit 12
46D13Data bit 13
47D14Data bit 14
48D15Data bit 15
49+5V+5 VDC
50+5V+5 VDC

D0-D15

Unbuffered data bus, bits 0 through 15

A1-A23

Unbuffered 68HC000 address bus, bits 1 through 23

16M

16 MHz system clock

/EXT.DTACK

External data transfer acknowledge that disables main system /DTACK.

/AS

68HC000 Address strobe

/DTACK

Data transfer acknowledge, /DTACK input to 68HC000.

/DELAY_CS

This signal is generated by the addressing PAL and is used to put the ROM board into the idle mode by inserting multiple wait states.

/ROM_CS

Permanent ROM chip select signal. Selects in range $90 0000 through $9F FFFF.

Apple Macintosh Portable Processor-Direct Slot (PPDS) connector pinout

Apple Macintosh Processor-Direct Slot (PDS) connector pinout