Panasonic memory expansion
September 20th, 2014
A little project again: an 8k SRAM expansion for the JR-200. In the end, a rather simple exercise in address decoding with a GAL and wiring the expansion bus signals to the memory chip. Quite many wires there – was losing my hope at one point.
The kludge resides at $8000–$9FFF, right after the standard RAM. You can load code there with mload and run it normally with usr. The BASIC is not aware of the extra mem, so after the boot you’ll just see the standard amount displayed. Further details such as the GAL function can be found on my dedicated JR-200 page.
Kommentin kirjoitus
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