>>>Has anyone come across a spem internal memory expansion? >>> >>>How was this implemented in the QL? >>>Was it one that simply plugged into the 8301 socket - with through >>>connector and wired to the 68008? >> >>I had one some years ago. This one is plugged into the 8301 socket, bat >>the added memory is handled by 8301 like original memory. >>Pins 2,3 and 10 of the ZX8301 are plugged outside the original socket >>disconnecting in fact A17, A16 and CAS1L; new signals A17,A16 and CAS1L >>are generated by PAL16L8 using also A19 and A18 by the 68008. PAL16L8 >>generates also a new address line for 41256 memories, CAS0L and CAS1L >>for two blocks of 256 Kbytes memory >.. so there is no connection outside the 8301 then.
Only address lines A18 and A19 from 68008. Main boards issue 6 or 7 may require to connect a third wire if you get only 192 Kb of memory instead of 640 Kb. Unfortunately I do not remember further details about this link (-: Apologies again for my poor English. Bye.
