Difference between revisions of "ASIC"
From CPCWiki - THE Amstrad CPC encyclopedia!
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Application-Specific Integrated Circuit (ASIC) | Application-Specific Integrated Circuit (ASIC) | ||
| − | An ASIC is an especially manufactured custom | + | An ASIC is an especially manufactured custom chip designed to fulfil special functions. |
| − | The main reason is to perform special tasks or combine different electronic | + | The main reason is to perform special tasks or combine different electronic components into a single Integrated Circuit (chip). |
==Amstrad Custom chips== | ==Amstrad Custom chips== | ||
| − | The Amstrad CPC used one custom chip : the video [[Gate Array]] (also called VGA | + | 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" to merge the VGA and the CRTC. | Latter [[CPC]] cost down series included a "pre-ASIC" to merge the VGA and the CRTC. | ||
| − | The Amstrad [[Plus]] | + | The Amstrad [[Plus]] included a "second heart" simply referred as the ASIC. |
CPC+ ASIC's part number is 40489 | CPC+ ASIC's part number is 40489 | ||
| − | This Amstrad Plus ASIC perform many | + | This Amstrad Plus ASIC perform many additional features that the old CPC series couldn't: the "Plus Features". |
*Hardware Sprites. | *Hardware Sprites. | ||
*[[CRTC]] emulation. | *[[CRTC]] emulation. | ||
| − | *Hardware | + | *Hardware Scrolling. |
| − | *Maybe some interactions with the [[Amstrad Cartridge Identification Device|ACID]] chip in | + | *Maybe some interactions with the [[Amstrad Cartridge Identification Device|ACID]] chip in cartridges. |
*DMA sound channels. | *DMA sound channels. | ||
*Many many more. | *Many many more. | ||
| Line 27: | Line 27: | ||
== Known Flaws== | == Known Flaws== | ||
| − | The | + | The Amstrad Plus ASIC improved a lot of the old CPC's capability. |
Yet this was a bit flawed. | Yet this was a bit flawed. | ||
*Despite removing some tasks from the CPU ([[Z80]]), the ASIC had to use specific central memory addresses, so "took away" this memory from the CPU... | *Despite removing some tasks from the CPU ([[Z80]]), the ASIC had to use specific central memory addresses, so "took away" this memory from the CPU... | ||
| − | + | This was not that important for a 64KB RAM system (464+ and GX4000) yet this is a serious limitation when dealing with Extra memory (6128+ and Extra RAM peripheral) | |
*There's a DMA bug (Help needed). | *There's a DMA bug (Help needed). | ||
| − | *Some argue that the | + | *Some argue that the ASIC simply badly emulates an old CPC, but it is not really one. The colours are slightly different and some software (games) couldn't work until modified (patches for such old CPC games often exist now). |
| − | As a result, some people say that the Plus is not a CPC | + | As a result, some people say that the Plus is not a CPC. |
| Line 55: | Line 55: | ||
*[http://en.wikipedia.org/wiki/Application-specific_integrated_circuit ASIC at Wikipedia] | *[http://en.wikipedia.org/wiki/Application-specific_integrated_circuit ASIC at Wikipedia] | ||
| − | General | + | General information on ASICs. |
*[http://www.kjthacker.f2s.com/docs/arn5new.html Asic and Plus features at Unofficial CPC ressources 1.4] | *[http://www.kjthacker.f2s.com/docs/arn5new.html Asic and Plus features at Unofficial CPC ressources 1.4] | ||
*[http://www.kjthacker.f2s.com/docs/arnold5a.html Asic and Plus features at Unofficial CPC ressources 1.5] | *[http://www.kjthacker.f2s.com/docs/arnold5a.html Asic and Plus features at Unofficial CPC ressources 1.5] | ||
| − | *[http://www.kjthacker.f2s.com/docs/cpcplus.html Extra Plus Hardware | + | *[http://www.kjthacker.f2s.com/docs/cpcplus.html Extra Plus Hardware Information] |
[[Category:CPC Plus]][[Category:Hardware]][[Category:Programming]][[Category:Datasheet]][[Category:Graphic]] | [[Category:CPC Plus]][[Category:Hardware]][[Category:Programming]][[Category:Datasheet]][[Category:Graphic]] | ||
[[Category:Stub]] | [[Category:Stub]] | ||
Revision as of 08:17, 26 October 2009
Application-Specific Integrated Circuit (ASIC)
An ASIC is an especially manufactured custom chip designed to fulfil special functions.
The main reason is to perform special tasks or combine different electronic components into a single Integrated Circuit (chip).
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" to merge the VGA and the CRTC.
The Amstrad Plus included a "second heart" simply referred as the ASIC.
CPC+ ASIC's part number is 40489
This Amstrad Plus ASIC perform many additional features that the old CPC series couldn't: the "Plus Features".
- Hardware Sprites.
- CRTC emulation.
- Hardware Scrolling.
- Maybe some interactions with the ACID chip in cartridges.
- DMA sound channels.
- Many many more.
Known Flaws
The Amstrad Plus ASIC improved a lot of the old CPC's capability. Yet this was a bit flawed.
- Despite removing some tasks from the CPU (Z80), the ASIC had to use specific central memory addresses, so "took away" this memory from the CPU...
This was not that important for a 64KB RAM system (464+ and GX4000) yet this is a serious limitation when dealing with Extra memory (6128+ and Extra RAM peripheral)
- There's a DMA bug (Help needed).
- Some argue that the ASIC simply badly emulates an old CPC, but it is not really one. The colours are slightly different and some software (games) couldn't work until modified (patches for such old CPC games often exist now).
As a result, some people say that the Plus is not a CPC.
Internal Links
External Links
General information on ASICs.
