1MB RAM expansion

[Fran123]

Hello

I recently got a 1MB RAM memory module.
Now, how do I access the banks?

Thank you.

[McArti0]

Use search on main cpcwiki.eu

https://www.cpcwiki.eu/index.php/Standard_Memory_Expansions

[Prodatron]

See here:
https://www.cpcwiki.eu/index.php/Standard_Memory_Expansions#Extended_1M-4M_Expansions_.28RAM7.2FYarek-style.29
For an 1MB expansion you only have the upper bits "aaa" as 111 (=#7Fxx, first 512K) and 110 (=#7Exx, second 512K).

For the RAM configs ("ccc"), see here:
https://www.cpcwiki.eu/index.php/Gate_Array#Register_3_-_RAM_Banking

[Fran123]

Thanks, I have already managed to access the memory banks.

Now, I have a dubt: How mouch memory do I have?  1MB?  1MB+64K?  1MB+128KB?

[Prodatron]

1MB + 64K

Memory expansions with sizes >=512K will deactivate the second 64K of the 6128 (usually).

These expansions with <512K (e.g. 256K) are placing the additional 64K at bank 4,5,6,7, while bank 0 remains the second 64K of the 6128, and banks 1,2,3 are not available.

[GUNHED]

The exception is the X-MEM: With a CPC6128 or 6128plus there are 512 KB + 128 KB. One block of 64 KB is banked in via &7EC4,5,6,7.