konkotgit / msx-spider-cart

Cartridge for MSX Computers

MSX Spider Cart

Very Simple Cartridge for MSX Computers

With this PCB you can build your own MSX ROM cartridges.

You can use 8, 16 or 32kB ROM file.

Important

To program the 32kB ROM correctly, you need to prepare the ROM file by swapping two 16kB blocks.

You can use simple windows CLI tool swapROM

The 32kB EPROM occupies address 4000h to BFFFh in the address space because it is using CS1 as read enable.

A14 will be high from 4000h to 7FFFh and low from 8000h to BFFFh. So A14 actually needs to be inverted.

By swapping the two areas no inverter is required.

How to build cartridge

27C256 EPROM (MAX 32KB ROM)

Solder only capacitor C1

Only one of CS1, CS2 or CS12 should be closed.

W27C512 EEPROM (MAX 2 x 32KB ROM)

Solder capacitor C1, resistor R1 and goldpins for JP1 jumper.

Solder goldpins for CS1, CS2 and CS12 jumper.

Only one of CS1, CS2 or CS12 should be closed.

Jumper JP1 must be closed on 1/2 or 2/3 position

Look at YouTube:

msx-spider-cart's Issues

Suggestion to add to readme

The 32Kbyre EPROM occupies address 4000h to BFFFh in the address space because it is using CS1 as read enable. A14 will be high from 4000h to 7FFFh and low from 8000h to BFFFh. So A14 actually needs to be inverted. By swapping the two areas no inverter is required.

BTW: A15 is not connected but actually has the correct levels for both areas, so swapping A14 with A15 is also a solution.

Would be possible to publish the kiCad files?

I would like to modify a bit the form factor of the cartridge to make it compatible with old konami cases.
Would you please include the kiCad files (or any other format that can be edited)?

Thanks!