Hi Richard,
I have a quick question - the diagram online still shows 27C256 pin 20 connected to 74LS139 pin 12 and 6164 pin 20 connected to 74LS139 pin 11. Should these two signals be swapped? JP Grobler mentions he swapped them; I think in order to get the memory map above they do need to be swapped.
Yes, you're right. The correct conections are:
74LS139 pin-12 -> 6164,pin-20 pin-13 -> 27c256,pin-20
I'll soon release an updated version of the documentation containing all the fixes and sugestions.
I'll probably build this as a seperate ROM cartridge; my Toshiba unit is already stuffed full of the 41256 sample DRAM mod and it would be difficult to squeeze an extra SRAM chip into it. With the Toshiba ROM removed it's effectly an I/O device only, so an MSX-AUDIO ROM BIOS cartridge could be plugged into a different slot.
Maybe there could be a way to build a single board containing both upgrades on it.
Regards, FRS _______________________________________________ MSX mailing list (msx@stack.nl) Info page: http://lists.stack.nl/mailman/listinfo/msx
