cbmeeks wrote:
I could only find them on Mouser (which I use all the time anyway) but I thought I saw that none were in stock. Something like 98 were "on order". That's for through-hole, anyway.
And the SMD version only had like 30-something in stock. So I just took it as a device that isn't in high demand (and perhaps, near EOL).
Both forms of the 65C816 are current production. Mouser's stock ebbs and flows, and at the end of the year, tends to ebb in order to reduce the inventory value for tax purposes.
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The idea of using a "6502 with 24bit address bus" does sound appealing.
If I went that route, I'd want to use a microcontroller (if possible) to do address decoding and not use a CPLD or anything like that. Trying to keep it as hobbyist friendly as possible.
So, any tips on using the '816 and a microcontroller to address 512k RAM?
I don't think you'd be terribly impressed with the performance of such a combination. It can be done entirely with discrete logic, but is really a job for a CPLD. CPLDs exist for a reason, and that is to create elaborate glue logic without incurring significant performance penalties. Microcontrollers are not particularly well-suited to bare metal glue logic functions and tend to handle them relatively slowly. You should pick the proper tools for the job.
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Also, I'm thinking it might be more helpful if I explained a little more on what I want to use the memory for.
I'd be happy with restricting 64K for code execution and the rest as bankable buffers for things like graphics, char sets, audio, etc.
If you use the 65C816 as it is intended to be used with one of Garth's DIMMS, you'd have 4MB of RAM, with contiguous addressing spanning from
$010000 to
$3FFFFF, which is 3.93MB. That would be lots of room for your planned data structures.