C64 <-> CS/A65 bus adapter
This is the description of an adapter to use most CS/A boards in a C64. A lot of CS/A boards, including a video card, serial interfaces, floppy controller and an SCSI card can be found on the CS/A65 homepage.
The interface itself is, in fact, pretty simple. It is a board that is plugged into the C64 expansion port. On the other side it provides a socket for a CS/A bus card. Two things have to be considered for the schematics:
- The C64 Video chip releases the bus with rising Phi2. This is too late for the 6522. Thus the rising edge of Phi2 must be delayed to the CS/A bus, to be sure. The CS/A bus is specified to run up to 2 MHz, so there is no speed problem.
- The I/O area in the C64 is 256 byte only. To cover the whole CS/A bus address space (1M memory and 4k I/O) additional address lines have to be generated. This is taken care of with a VIA 6522 on the adapter. More in the description.
News:
- 2006-12-16 Added an Eagle schematics board version.
Table of content
Board revisions
Version: 1.0C
Status: ok
Notes
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This board only works with a C64 - not with a C128! |
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The layout could be better. If you have long plugs for the video and IEC, they may conflict with the CS/A card in the adapter board. |
Files
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c64_csadapter-v1.0c.sch |
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c64_csadapter-v1.0c-sch.png |
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c64_csadapter-v1.0c.brd |
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c64_csadapter-v1.0c-brd.png |
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c64_csadapter.jpg |
Version: 1.0B
Status: ok
Notes
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This board only works with a C64 - not with a C128! |
Files
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c64csa.jpg |
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c64csadesc.txt |
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c64csaparts.txt |
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c64csa.png |
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c64csa.ps.gz |
