[[File:Iram640.jpeg|thumbnail|iRAM/640 for the CPC 6128]][[File:Iram1024.jpg|thumbnail|iRAM/1024 for the CPC 464/664]]
CPC iRAM is a the first [[Standard_Memory_Expansions|standard]] compatible, internal plug & play RAM expansion series for the CPC range of computer and provides up to 1MB of expanded RAM. All variations are open source, DIY friendly, internal RAM expansions for and sit in the CPC 6128 CPU socket with no further cabling and CPC 464/664 (later hopefully also for no additional soldering inside the Plus/GX4000)CPC.
== Compatibility == No incompatibilities have been reported so far for the 6128 version. The iRAM expansion sits in first revision of the CPU socket and requires no additional soldering inside 464 version has been found to be incompatible with the CPC[[M4_Board|M4 Board]]. [https://github.com/etomuc/CPC464-iRAM1024/blob/main/README_rev1.md#modification-for-m4-incompatibility A patch has been published].
The first 512K of expansion RAM follow the [[Standard_Memory_Expansions#Standard_128K-512K_Expansions_.28dk.27tronics.2Fdobbertin-style.29|DK'Tronics addressing mode standard]], giving up to 576K of RAM to legacy software. More modern software that supports the [[Standard_Memory_Expansions#Extended_1M-4M_Expansions_.28RAM7.2FYarek-style.29|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 Available versions ==
=== CPC 6128 - iRAM/640 ===
* 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.
StatusRepository: Released - see https://github.com/etomuc/CPC6128_iRAM-640 ''Note: Meanwhile a commercial product is available at Lotharek.pl which also claims to offer 640K and is even smaller, not much larger than the CPU socket itself. However not much information can be found except for the shop.''
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iRAM1088.jpg|iRAM/1088 for CPC 6128
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* 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.
StatusRepository: Released - see https://github.com/etomuc/CPC6128_iRAM-1088 == currently in development ==
=== CPC 464/664 - iRAM/1024 ===
* for CPC 464 and 664
* offers two sockets for SRAMs* upgrade to 576K (1 SRAM) or 640K/1024K (2 SRAMS)* first SRAM: Upgrade to 576K, following the DK'Tronics standard without support of C3 mode (like many other RAM expansions) * second SRAM: upgrade to 1024K (512K SRAM) or optionally also 640K (128K SRAM)* including [http://norecess.cpcscene.net/advancedmemoryusage.html C3 RAM banking] supported if both support for 6128 compatibility* alternatively without C3 support 576K or 1088K (one or two SRAMs are fitted)
* easy to assemble, all through-hole components
StatusRepository: Finished, final PCB design will be tested, will be released in late 2025 == considered == === PLUS iRAM/1024 === * 1Mb upgrade for Plus series * less DIY friendly, probably needs more complex CPLDs (ATF1504) Statushttps: very early stage, still considering if it's feasible === GX iRAM/512 === * 512K upgrade for GX4000* less DIY friendly, probably needs more complex CPLDs (ATF1504) Status: just an idea == abandoned == === CPC 6128 - iRAM/640s === * minified iRAM/640* for CPC 6128* size just a tiny bit bigger than Z80 CPU socket* TSSOP SMD components below Z80* requires good soldering skills and special tools to program SMD CPLDs Status: fully designed, abandoned as it offers no advantage over DIY friendly version and would only benefit commercial sellers (Hint: Lotharek offers a similar expansion commercially for a good price) === CPC 464/664 - iRAM/1024s === * smaller than iRAM/1024, more similar in size to iRAM/640* for CPC 464 and 664* single 1MB SMD SRAM, upgrade to 1024K* [http://norecessgithub.cpcscene.netcom/advancedmemoryusage.html C3 RAM banking] supported* easy to assemble, mostly through-hole components but one SMD SRAM Status: working prototype === CPC 6128 - iRAM/576 === * for CPC 6128 only* 512K expansion* total accessible RAM of 576K in a 6128 (following the DK'Tronics standard)* easy to assemble, all through-hole components Status: Abandoned in favor of the iRAM/640 which uses the exact same components but offers more total memory. === CPC 464/664 - iRAM/512 === * for CPC 464/664* 512K expansion* total accessible RAM of 512K in a CPC, following the DK'Tronics standard and support of C3 mode. * or 576K without C3 support (512K_C3 etomuc/ 576K selection per manual switch)* easy to assemble, all throughCPC464-hole componentsiRAM1024
Status: Abandoned as CPC iRAM/1024 will fit into all 464s/664s and is more flexible
[[Category:Hardware]] [[Category:Memory expansions]] [[Category:DIY| ]]