CPC iRAM/1024 - 1MB internal RAM expansion for the Amstrad CPC 464 and 664

The iRAM/1024is a DIY friendly, internal RAM expansions for the CPC 464 and 664.

(For the CPC 6128 there is the iRAM/640 and iRAM/1088 expansion, see my other projects.)

The iRAM expansion sits in the CPU socket and requires no additional soldering inside the CPC.

The first 512K of expansion RAM follow the DK'Tronics addressing mode standard, giving up to 576K of RAM to legacy software. More modern software that supports the extended 1M-4M standard will be able to access all the provided RAM.

• 1024K expansion
• total accessible RAM of 1024KB
• C3 RAM banking support for 6128 compatibility (important to run CP/M plus, FutureOs and some 6128 games and demos)
• easy to assemble, all through-hole components
• PCB designed to fit into all CPC 464 and 664 versions

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Disclaimer

USE AT YOUR OWN RISK.

This is a hobby project, I am a hobbyist and no engineer. Although I have tested the expansion on several CPCs for many hours with many other expansions and lots of software, there is no guarantee that I did not make a mistake or that it will properly work under all circumstances, with all expansions or with all revisions of the CPC. There is also always the risk that the expansion can cause harm to your CPC.

Especially if you are building this for others (commercially or not) make sure to make your own intense tests to guarentee this expansion works as expected before handing over to the recipients. I would strongly recommend to try a small batch first before doing bigger batches.

USE AT YOUR OWN RISK.

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Notes:

• You need to program the ATF16V8 ICs before soldering them to the board. They cannot be programmed afterwards. (Many current EPROM programmers can do the programming - see Github for full details)
• 100nF capacitors need to have a 2.54mm footprint
• instead of the 74HCT174 the 74LS174 can also be used
• Project repository with detailed BOM and assembly instructions: https://github.com/etomuc/CPC464-iRAM1024

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License:

The project is released under the CC BY-NC-ND 4.0 license with the following exception: Commercial production and selling is permitted as long as the final product will be sold for a maximum of USD 40 / €40 / £38 or the equivalent in other currencies (excl. shipping and platform fees like e.g. for Ebay or SellMyRetro)..