My PHCC board uses several interface cards. It uses a bus that is very similar to that of the Phunsy computer.
A 1 +5 Volt div C 1 +5 Volt div
A 2 x C 2 D7 P4-04
A 3 x C 3 D6 P4-05
A 4 x C 4 D5 P4-11
A 5 x C 5 D4 P4-10
A 6 x C 6 D3 P4-09
A 7 x C 7 D2 P4-08
A 8 DispmemReq P3-15 C 8 D1 P4-07
A 9 PromReq P3-16 C 9 DO P4-06
A1O OpAck• P13-14 C1O WRP P5-10
A11 x C11 R/W• P5-13
A12 WritExtReq P3-5 C12 OPREQ P5-15
A13 ReadExtReq P5-14 C13 M/IO• P5-01
A14 x C14 A14-D/C• P5-02
A15 x C15 A13-E/NE• P5-11
A16 x C16 A12 P5-06
A17 x C17 A11 P2-01
A18 unused (IRQ in) C18 A1O P2-04
A19 unused (IRQ out) C19 A 9 P2-15
A20 x C20 A 8 P2-09
A21 x C21 A 7 P2-08
A22 x C22 A 6 P2-06
A23 x C23 A 5 P2-07
A24 x C24 A 4 P2-13
A25 x C25 A 3 P2-16
A26 x C26 A 2 P2-11
A27 x C27 A 1 P2-10
A28 x C28 A 0 P2-05
A29 RESET• P3-7 C29 x
A30 x C30 Clock• 14 MHz P5-3
A31 GND div C31 GND div
A32 @ +12 Volt C32 @ -5 Volt
@ = not from main CPU board
• = inverted
DispmemReq = A14• A13• A12 A11• OpReq (0x1000 to 0x17ff and OpReq, combine with M/IO•)
PromReq = A14• A13• A12 • OpReq (0x000 to 0xfff and OpReq, combine with M/IO• and R/W•)
WritExtReq = (R/W•)• (M/IO•)• A13-E/NE• OpReq
ReadExtReq = R/W• (M/IO•)• A13-E/NE• OpReq