== Description ==
4 MB DRAM internal memory expansion for CPCCPC6128.
* Its first 512 Kbyte are compatible with external memory expansions (Dk'tronics, Inicron RAM expansion, SYMBiFACE II etc.), using port #7Fxx (see [[Standard Memory Expansions]]).
* Its first 2 MB are compatible to RAM7's 2 MB expansion.
* The whole 4 MB can be used trough ports #78xx to #7Fxx (see [http://8bit.yarek.pl/upgrade/cpc.cpc4mb/index.html CPC4MB] Page, for futher details).
* the expansion connects to the PAL inside the 6128.
* all configuration codes are supported (0-7) and work exactly as they do in a 6128.
* I/O port decoding is: 0xxxxbbbxxxxxxxx (confirmed by TFM) where bbb are 3 bits of the bank. The other 3 bits are from the data decoded as 11bbbccc and ccc the configuration code. Yarek's site recommends that bits A14,A13,A12,A10 are set to 1 to avoid conflict with other hardware.
== Software ==