Difference between revisions of "CPC iRAM"

Revision as of 15:25, 6 January 2026

iRAM/640 for the CPC 6128

iRAM/1024 for the CPC 464/664

CPC iRAM is a series of open source, DIY friendly, internal RAM expansions for the CPC 6128 and CPC 464/664 (later hopefully also for the Plus/GX4000).

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

Compatibility

No incompatibilities have been reported so far for the 6128 version.

The first revision of the 464 version has been found to be incompatible with the M4 Board. A patch has been published and is currently tested. Further revisions will include the patch once tests have been successful.

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.

External memory expansions will be ignored once the iRAM is installed. This can be useful for external feature-expansions that also provide a RAM expansion and usually cannot be used in parallel with other (external) RAM expansions. A great use case is to put the ULIFAC in ROM board mode which replaces the full or parts of the ULIFACs RAM with ROM slots. Now with the iRAM installed the CPC still has access to the full RAM provided by the iRAM. If needed a disable switch can optionally be connected to disable the internal iRAM from outside the CPC without removing the iRAM.

released

CPC 6128 - iRAM/640

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  iRAM/640

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  iRAM/640 built-in

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  RAM Test

• for CPC 6128 only
• 512K expansion
• total accessible RAM of 640K in a 6128 (64K Base RAM + 512K RAM expansion + 64K secondary RAM bank of the 6128)
• easy to assemble, all through-hole components
• perfectly fits into a CPC 6128, even with socketed ROM or RAM. In Schneider CPC 6128 the metal shielding needs to be removed or altered.

Status: Released - see https://github.com/etomuc/CPC6128_iRAM-640

Note: Even smaller commercial alternative available by Lotharek.pl

CPC 6128 - iRAM/1088

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  iRAM/1088 for CPC 6128

• for CPC 6128 only
• 1024K expansion
• total accessible RAM of 1088K in a 6128 (64K Base RAM + 1024K RAM expansion)
• easy to assemble, but SRAMs are in SMD packaging (SOP32) due to size constraints in the CPC 6128
• perfectly fits into a CPC 6128, even with socketed ROM or RAM. In Schneider CPC 6128 the metal shielding needs to be removed or altered.

Status: Released - see https://github.com/etomuc/CPC6128_iRAM-1088

CPC 464/664 - iRAM/1024

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  iRAM/1024 for CPC 464/664

• 

  SymbOS on CPC 464

• for CPC 464 and 664
• upgrade to 1024K including C3 RAM banking support for 6128 compatibility
• alternatively without C3 support 576K or 1088K (one or two SRAMs fitted)
• easy to assemble, all through-hole components

Status: Released - see https://github.com/etomuc/CPC464-iRAM1024