What brings my old (2021) SRAM cartridge back to the fore is my latest build of the Clone Electron with the new ULA. I wanted to use MMFS instead of my usual Slogger Pegasus 400 / Gotek setup for testing the Clone board.
Initially when building a small SD card Printer Port module I used my BBSRAMextreme cartridge to hold the MMFS ROM image (The benefit of using the SRAM version of MMFS is it keeps PAGE at &E00). It was not very practical for day-to-day use as it's a bit of a waste using this cartridge for just one application.
So when thinking about a simpler MMFS solution for the Clone I first thought of using the PLUS 2 sideways RAM option with the self relocating MMFS/2 ROM image but this forces me to have two sideways RAM banks, 14 & 15, and use a ROM slot - not perfect as I have already allocated these two banks to Mode 7 and the 2nd processor ROMs.
I then took a look at my pile of cartridges and came across my original SRAM cartridge from a few years ago. This cartridge provides two banks of sideways RAM but also uses two 62256 RAM chips. When I was putting the design together I ensured each socket was compatible with 27128 EPROMs so by simply replacing one RAM IC with a ZEMMFS programmed EPROM it becomes a neat disk (SD) interface when used in conjunction with the SD Module.
The original SRAM module from 2021.
With the EPROM replacing the RAM IC.
The SRAM/EPROM catridge with the SD Module.
Two options for the SD Module - left or right facing.
Installed on the Clone board
and a ROM listing showing the ROM and the relocated RAM version.
