ElkSD-Plus 1 Acorn Electron SD Interface & 48K RAM Expansion




About this device

The ElkSD64 has proved to be extremely popular, but people regularly asked if there was a version that would work with the Plus 1 expansion. Now there is. The ElkSD-Plus 1 is a combined SD card interface and RAM expansion in cartridge form, which works in a Plus 1 cartridge slot.

It's not just an ElkSD64 squished into a cartridge case, it actually boasts a couple of new features.

The ElkSD-Plus 1 is cable of using two seperate versions of the MMFS filesystem, switchable either by jumper or in software. By default MMFS 1.4x is used, ensuring maximum compatibility and stability. But MMFS 2 is also available, which some people will prefer as it enables easier use of .SSD images but at the cost of breaking compatibility with game launcher menus.

Another new feature is the failed flash recovery system. If a problem occurs when updating the ElkSD-Plus 1's software setting a jumper will enable the cartridge to boot from a backup copy of MMFS and be able to re-run the update flashing process.

The Plus 1 cartridge slots are limited to two 16K memory banks per cart, as one bank is used by MMFS this means the 32K of RAM on the ElkSD64 has had to be reduced to 16K on the ElkSD-Plus 1.

Update, May 2020: All ElkSD-Plus1 cartridges now shipping are revision 2.0 models. These remove the ability to use MMFS2 and the flash recovery system, using the freed up logic space to implement a hardware SPI controller that increases read and write speeds by around 4x.

The ElkSD-Plus 1 revision 2 cartridge is now shipping in limited volume. You can buy one through Ebay



File Contents Description Last Updated
elksd.zip 32K Electron Games A small curated collection of Electron games, runs from SD card on all Electrons. 21/08/2019
elkbig.zip Lots of Electron Games A large third-party collection of Electron games, some need sideways ram to run. 15/01/2020
ESDP1_Guide.pdf User Manual (1.x) ElkSD-Plus 1 full user guide. 15/01/2020
elkp1_inst.pdf Installation Instructions (1.x)   03/11/2019
elksdp1_inst.pdf Installation Instructions (2.x)    21/05/2020
ElkSDP1_v2_Guide.pdf  User Manual (2.x) ElkSD-Plus 1 full user guide.




The ElkSD-Plus 1 has a very high rate of compatibility. In default configuration PAGE is located at $E00 with the interface fitted, which means almost all Electron games will run without issue.