[Coco] CocoSDC

[camillus.b.58 at gmail.com]

Hi, I was thinking, is it short of ram for code or for data?

I wonder if you could integrate some external fast ram that is accessable over 1-wire.

If it is for expanding the code then that is the hardpart, because you then have to fix a block of ram in the 328 and that block needs to be transfert into the external memory pool. kind like a MMU. This approach has some overhead on code, because youu have to keep track of what is where and when what needs to be back in the fixed erea to have a smooth code continuation.

Also have to program with short jump, at least within the fixed block. And copying datablocks cost time, so it needs to take into account that time sensitive code can not be transfert, it simple takes to long. this means that those code segments needs to be in the beginning of the 328.





If it is just for data store then the extra ram is just an extension from EndRamAddress328+1 to EndExternalRam.



Hope this make any sence, and now you can loose some sleep over it….LOL




Camillus 






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From: RETRO Innovations
Sent: ‎Tuesday‎, ‎October‎ ‎14‎, ‎2014 ‎12‎:‎28‎ ‎AM
To: CoCoList for Color Computer Enthusiasts





It's possible to do IDE, SDHC, FAT16/32, LFN, and multiple partitions in 
~1000 bytes of RAM and ~12kB of FLASH (as I've implemented it in C), so 
I guess it mainly depends on how much of the M328 is still left.  Shame 
there is no M648 for the hobbyist market, as that would make it an easy 
answer.

Jim



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