On Thu, 22 Feb 2001 ncoplin@orbeng.com.au wrote: > I have a vague memory of the C128 being expandable to 256k and the internet > documents for C128 memeory banking talk about there being RAM banks 2 and 3. > > How does one expand their C128 in this way? The way I did it was that I piggy-backed another MMU on top of the original one and added some glue logic that swapped some data pins on the second MMU (I think D6 and D7) when the memory configuration registers were addressed. The RAM bank selection signals (those that are connected to -CAS on the RAM chips) from the new MMU were wired to RAM banks 2 and 3. The document and the schematic diagram is at <URL:http://www.funet.fi/pub/cbm/documents/projects/memory/c128/1028/>. The expansion consists of two independent expansions: one that expands each RAM bank from 64k to 256k, and another that doubles the amount of RAM banks from 2 to 4. Marko - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail cbm-hackers-request@dot.tml.hut.fi.
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