Amstrad PPC640 expansion ports

This is a fairly large mailing list, but I suspect it was me who said that. In any cas, I do have those manuals... Sure, here you are. Expansion A (DB25) 1 +5V _input_ 2 T/C 3 A19 4 A17 5 A15 6 A13 7 A11 8 A9 9 A7 10 A5 11 A3 12 A1 13 AEN 14 Ground 15 DACK0/ 16 A18 17 A16 18 A14 19 A12 20 A10 21 A8 22 A6 23 A4 24 A2 25 A0 Expansion B (DC37) 1 -20V 2 IRQ2 3 IRQ4 4 IRQ6 5 I/O Rdy 6 DACK2/ 7 I/O CHCK/ 8 DRQ2 9 CK14 (Osc) 10 MEMR/ 11 I/OR/ 12 ALE 13 D7 14 D5 15 D3 16 D1 17 -5V input 18 -12V input 19 Ground 20 +12V Input 21 IRQ3 22 IRQ5 23 IRQ7 24 DACK1/ 25 DACK3/ 26 DRQ1 27 DRQ3 28 MEMW/ 29 IOW/ 30 RESET (out) 31 CK4 (Clock) 32 D6 33 D4 34 D2 35 D0 36 +12V input 37 +5V input Note that the power lines are inputs -- the machine is powered from the expansion unit, not the other way round. Many of the signals come from irreplaceable custom chips, and should be buffered (Amstrad suggest using a 74HC244 for this). In particular, the following 16 signals need to be buffered : A0-A7 IOW/ IOR/ MEMW/ MEMR/ ALE RESET CK14 CK4 The data bus should be pulled high by external 10k resistors. You can connect an 8 bit ISA card by matching up the signals, but I would still advise buffering the 16 signals I mentioned. Note that you need to provide an external PSU as well. -tony