Amiga Expansion Bus A.K.A Zorro I pinout

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These are the connections found at the side of the Amiga 1000 and Amiga 500 computers. They are electric and mechanical compatible with the single exception of being rotated 180 degrees looking at it from the top of the PCB this can cause trouble connecting a expansion meant for the A1000 into the A500 and vice versa. This Bus is like most Buses at this time a extension on the CPU Bus.

 

Pin Number	Pin Name	Description
1	Gnd
2	Gnd
3	Gnd
4	Gnd
5	Vcc
6	Vcc
7	7MHz
8	-5V
9	NC
10	+12V
11	NC
12	Gnd
13	Gnd
14	_CCKQ
15	_CCK
16	XRDY
17	CDAC
18	_OVR
19	_INT2
20	NC
21	A5
22	_INT6
23	A6
24	A4
25	Gnd
26	A3
27	A2
28	A7
29	A1
30	A8
31	FC0
32	A9
33	FC1
34	A10
35	FC2
36	A11
37	Gnd
38	A12
39	A13
40	_IPL0
41	A14
42	_IPL1
43	A15
44	_IPL2
45	A16
46	_Berr
47	A17
48	_VPA
49	Gnd
50	E
51	_VMA
52	A18
53	_RST
54	A19
55	_HLT
56	A20
57	A21
58	A22
59	A23
60	_BR
61	Gnd
62	_BGACK
63	D15
64	_BG
65	D14
66	_DTACK
67	D13
68	R_W
69	D12
70	_LDS
71	D11
72	_UDS
73	Gnd
74	_AS
75	D0
76	D10
77	D1
78	D9
79	D2
80	D8
81	D3
82	D7
83	D4
84	D6
85	Gnd
86	D5

There is another pinout listed in the A500 technical reference:

Pin    Name
1    GND
2    GND
3    GND
4    GND
5    +5v
6    +5v
7    exp
8    -12v
9    exp
10    +12v
11    exp
12    CONFIG
13    GND
14    C3
15    CDAC
16    C1
17    OVR
18    XRDY
19    INT2
20    PALOPE
21    A5
22    INT6
23    A6
24    A4
25    GND
26    A3
27    A2
28    A7
29    A1
30    A8
31    FC0
32    A9
33    FC1
34    A10
35    FC2
36    A11
37    GND
38    A12
39    A13
40    IPL0
41    A14
42    IPL1
43    A15
44    IPL2
45    A16
46    BERR
47    A17
48    VPA
49    GND
50    E
51    VMA
52    A18
53    RES
54    A19
55    HLT
56    A20
57    A22
58    A21
59    A23
60    BR
61    GND
62    BGCAK
63    PD15
64    BG
65    PD14
66    DTACK
67    PD13
68    PRW
69    PD12
70    LDS
71    PD11
72    UDS
73    GND
74    AS
75    PD0
76    PD10
77    PD1
78    PD9
79    PD2
80    PD8
81    PD3
82    PD7
83    PD4
84    PD6
85    GND
86    PD5
 

Comment: Pin 8 measures -5V on some Amiga 1000, however, on some Amiga 500s (Rev 6a and Rev 5) it measures -12V.