After a seller goes out of business or stops supporting a product line, before IPs (Instruction set Processors) like [[CPLD]] or [[FPGA]], they essentially became unavailable. [[Commodore_64#ICs|Commodore]] used a plethora of ASICs in their machines (VIC, SID, PAULA,......); [[MSX]] or the [[IBM PC]]/XT/AT were the opposite in using only [[COTS]] components, making it easy for third parties to offer parts (or to re-build and repair the computers for as long as the COTS chip was still available or a backwards-compatible component exists).
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==Amstrad Custom chips==
CPC+ ASIC's part number is 40489
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==Emulated chips==
* Printer Port Data and Strobe
* Floppy Motor enable [[flip-flop]], Floppy Address decoding (FDC chip Select)
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==New features==
*Specific ROM switching
*8-bit printer port (with bit3 of CRTC register 12)
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== DMA commands ==
* The STOP instruction will leave the source address register pointing to the next instruction, so that the instruction stream can be continued after CPU intervention.
* The argument field (N) of the REPEAT instruction is actually the number of times the loop is taken. The block of code between REPEAT and LOOP instructions is therefore executed N+1 times.
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== Known Flaws==
*Original CPC colors emulation is not correct.
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==Internal Links==
*[[CRTC]]
*[[Gate Array]]
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==External Links==
*[http://www.cpctech.org.uk/docs/cpcplus.html Extra Plus Hardware Information]
*[http://quasar.cpcscene.net/doku.php?id=assem:asic Quasar ASIC documentation (in french)]
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[[Category:CPC Plus|*]][[Category:Electronic Component]][[Category:Programming]][[Category:Datasheet]][[Category:Graphic]]
[[Category:Stub]][[Category:CPC Internal Components]]