On Thu, 29 Nov 2001, Richard Kilpatrick wrote: > comp.sys.msx seems to be slowing down so I am trying this group instead!
Hullo Richard! Fancy seeing you here... > I'm thinking about the MSX2 upgrade (CX7) but can't find info about the > ROMs, only the memory. There's also no information on making the > battery-backed clock. The CX5MII (both 64K and 128K varieties) use the V9938 MSX2 graphics chip and S3527 "MPS". You'd need to source the RP5C01 battery back-up chip from somewhere and handle the address decoding yourself. Later MSX-ENGINE chips had the RTC built-in. http://www.msxhans.msx2.com/pdfshw/cx5mtm.pdf The V9938 was used for its 512 pixel text mode in the Yamaha machines; hence they still only have 16K of VRAM like other MSX1 machines. If you upgrade the VRAM to 128K using 4 41464 DRAM chips, and change the ROMs for MSX2 ones, you should have all the MSX2 functionality you need. The FM ROMs are contained in the small cartridge on the underside of the machine (FM Voicing II) and inside the actual expander cartridge. Both versions of the cartridge ROM are available (SFG-01 and SFG-05 have different ROMs), and if you have the SFG-01 you can upgrade the ROM to get the MIDI-IN features. The machine ROMs are regular MSX1 ROMs, and can be replaced with regular MSX2 ROMs although I'm not sure how they'll react to not finding an RTC present. > (I'll also swap the CX5MII/128 for a Sony or similar MSX2 with the > separate diskdrive/CPU unit - I believe I can make the SFG module work > with other machines?) You'd need to fashion an adapter yourself. It's possible but not really necessary if you already have a CX5(M)(II). The audio amplifier design in the Yamaha computers is better than that in some MSX2 computer schematics I have seen. Richard -- For info, see http://www.stack.nl/~wynke/MSX/listinfo.html
