SX-1, why would you set it to 2MB vs 4MB memory mapper?

By Swami

Rookie (20)

Swami's picture

17-11-2018, 23:52

This is specific to the SX-1 FPGA. I've just gotten one and trying to understand the options. For instance, there is a DIP switch to change between 2MB and 4MB mapper. I've searched around and found no explanation why the 2MB setting would ever be preferred over the 4MB setting. I assume both were available in cartridge form since the 2MB was probably first and remained a less expensive option, but I'm not sure of the importance of it on the SX-1 since 4MB is also standard. Do some utilities only support 2MB mapper? Thanks!

I did find it interesting that one game, Alien2.rom, loaded with the MegaRAM 8kb bank, but not the 16kb bank...oh to understand. Smile

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By Grauw

Enlighted (7530)

Grauw's picture

18-11-2018, 00:44

If software counts memory but doesn’t handle the value 256 (for 4MB) correctly due to the value overflowing (max byte value is 255), there can in theory be issues. However I don’t know of any software which actually does except the Unknown Reality demo. To me it seems to be a bit of an urban legend that mostly persists because people repeat it to each other. Anyway, that’s why. I keep it set to 4MB.

By Swami

Rookie (20)

Swami's picture

18-11-2018, 00:53

Okay, Thanks!

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