AVR-DOS and FLASH MEMORY IC (AT25SF081)

mattliker · Joined: 24 May 2008 Posts: 5

Hi, need help! Is any chance to use AVR-DOS with FLASH memory? I can't use SD card nor other similar device...
Thanks for any idea...

albertsm · Joined: 09 Apr 2004 Posts: 5915 Location: Holland

when you make a driver it can work. the chip you mention has a block erase of 4 KB minimum. So that one is not really suited.
the best would be if you can erase 512 bytes.
when your chip has plenty of sram you could read 4K, erase it and then write the other blocks. but that will increase write cycles.

imo you can best use special memory that internally keeps track of write locations so the writing is distributed in order to prevent flash failing.

anyway, in the libs you find _DriveWriteSector and _DriveReadSector and these are the routines that need to be implemented.
also, there is no format command so you must be able to format the memory you use in a pc.

the xramdrive sample shows how that could be solved.

laborratte · Joined: 27 Jul 2005 Posts: 299 Location: Berlin

There are some chips which might be interesting to you: XTSD01GLGEAG to XTSD08GLGEAG by a company named XTX. These are tiny flash chips with a (non-official) SD interface. They should work with the standard SD driver.
I didn't worked with them yet, but they popped up in my radar a few month ago...