MSX-VIDEO with dedicated 4 MB Mapper ...

By Yukio

Paragon (1540)

Yukio's picture

22-11-2014, 19:53

It is possible to assembly a 256KB,512KB,1024KB,2048KB or even a 4096KB Mapper into the VDP ...
Using a MMS (Memory Mapper System) to access the 16KB pages!
Running Naked in a Field of Flowers

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By Dreamerm42

Hero (625)

Dreamerm42's picture

22-11-2014, 20:29

umm only 192kbytes max in vpd msx and msx2+?

Creo que solo se podian montar 192kbytes maximo en esas vdps

By Grauw

Ascended (10768)

Grauw's picture

22-11-2014, 20:50

It should be possible with some extra logic between the VDP and the VRAM. Just like RAM can be memory mapped, no real reason why VRAM couldn’t be. Note that KdL’s One Chip MSX core has support for VRAM memory mapping.

Though personally, I think 128K is enough, and it’s difficult to expand existing machines so if you make software for it most machines won’t support it. Not a very appealing thought to me.

By o.geerdink

Hero (588)

o.geerdink's picture

22-11-2014, 22:18

Once there is useful software for it people will expand their vram??

But I'd rather see a cartridge with 16 bit memory mapper for plain RAM. Or maybe even better, a RAM extension that serves as VRAM and normal RAM, DMA from z80 to vram and vice versa as in a CPC Amstrad.

By Lord_Zett

Paladin (807)

Lord_Zett's picture

22-11-2014, 23:11

it easy to ad a extra 64k. but its not usefull you cant show it onscreen you cant use it in basic

By brawaga

Resident (56)

brawaga's picture

24-02-2021, 17:11

Maybe it worth to map only the extra 64k, and leave 128k intact for compatibility. I cannot imagine why you might want to map base 128k, this won't give you a freedom to extend number of active/displayed pages independently, whilst extra 64k is dedicated to extra storage of libraries of sprites/tiles etc. to be copied to base 128k, and paging whole 64k at once could be useful; and again, I could not imagine why you might want to page by 16k.