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Hello knowledgable people ..
The Csa mega midget racer uses on board 512k fast ram can I remove the 4 ram chips and expand this to a larger size ? Or is this simply impossible!
I know the card has a 32bit connector but I
Do not yet have the daughter card for it.
Just a thought...
Mike :-)
in a word: no.
Those are SRAM chips which are damn fast - you can use them to shadow ROM (csa-mmr SROM) or as fast RAM (csa-mmr SRAM)
If you have no daughtercard, use them as RAM...
thanks for the info nick
:-)
If you are rich enough you can create your own SRAM board with the 4Mb (must be 32bit wide) and hook the address & data lines from the connector.
No need for clock (SRAM doesn't need it) or RAS/CAS malarkey.
Maybe
When I worked for csa, I wrote an admem program to add 2mb of sram (using qty 4 512k x8 sram chips). These chips are the same 32pin dip and were a direct replacement. I don't know if I was using a standard csa-mmr or a prototype (it looked like a regular production board). I've been trying to get a few of these sram chips to try in my csa-mmr (the one I used to write the software is long gone). The chips are about $15/ each which is too much for me just for expirementing.
joekster, very interesting!
Could I ask if you know anything about the csa-mmr utility: I'd really like to see if it could be rewritten to load a ROM from disk into the Static RAM area...?
Sort of...
It is possible to write any data you wanted to the sram. The mmr would just flip a few address bits and then the kickstart memory range would be redirected there. This remap does not survive a reboot/reset. However this presents some issues. It would be like flipping the switch on a kickstart switcher while the computer is running... There was thought of using eproms instead of sram - but the kickstart image would be the same. You can always use the 030's mmu to softkick...
I was never trusted with the source code to their utility. I would write a stand alone program and send my source code to them for inclusion in the utility.
Ah yes, it uses the MMU... I forgot about that!
The csa-mmr does not use the mmu when shaddowing kickstart to sram. It is the logic on the mmr, even an ec030 can shaddow.
But, with an mmu, you can softkick. I think the cpu command supports this.
D'oh. I read MMR as MMU :)
It would be great to know the logic so we could expand the utility a little.
Perhaps time to dig out resource or whatever state of the art currently is!