'''Application-Specific Integrated Circuit''' (ASIC)
An '''ASIC''' is an especially manufactured custom chip designed to fulfil fulfill special functions.
The main reason is to perform special tasks or combine different electronic components into a single Integrated Circuit (chip). This chip is not commonly available ([[COTS]]), but has to be ordered as a genuine part, prices dictated by the seller. 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 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).
==Amstrad Custom chips==
The Amstrad CPC used one custom chip: the video [[Gate Array]] (also called VGA – no connection with the Video PC standard).
Latter [[CPC]] cost down series included a "pre-ASIC" -called ASIC to merge the VGA and the [[CRTC]].
The Amstrad [[Plus]] included a "second heart" simply referred as the ASIC.
CPC+ ASIC emulates the following chips :
* [[CRTC ]] 6845
* [[Gate Array]]
* [[PAL16L8|PAL]] (128K RAM paging)
* [[8255 PPI]]
* Printer Port Data and Strobe
* Floppy Motor enable [[flip-flop]], Floppy Address decoding (FDC chip Select)
==New features==