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 Post subject: Use the flashcart as a storage device?
PostPosted: Mon Apr 14, 2008 9:13 pm 

Joined: Sun Dec 04, 2005 10:52 pm
Posts: 13
Location: Ottawa, Ontario
Is there software available (or hardware documentation out there) that would let you configure a flashcart as a storage device? For example, it would be great to use a flashcart instead of SIO2PC or a floppy to store works-in-progress.


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PostPosted: Wed Apr 16, 2008 9:43 am 

Joined: Sat Jan 03, 2004 4:36 pm
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Location: Germany
Yes, documentation on the flashing process would be greatly appreciated.
However for the Flashcard, a special filesystem or dedicated application would be needed, as a flash chip can only erased in blocks.

But, for example, a short ROM based Filesystem handler that will hook into the D: handler and will redirect read requests for a certain Drive number to the Flash Card would be really nice, for example for storing Image Data.


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 Post subject:
PostPosted: Wed Apr 16, 2008 3:22 pm 

Joined: Sun Dec 04, 2005 10:52 pm
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Location: Ottawa, Ontario
Exactly. Depending on the block size different options may be possible - if it's 8k blocks only, it's not so appealing. But if flashing can be done with 256 byte blocks, implementing a file system would be trivial - just use a similar model to a DOS.

I'm having visions using an 8Mb cart, plugged into a keyboardless XEGS, with some sort of SIO hub plugged in, where other unmodified Ataris can plug in and all access the data... sort of an SIO network, but more robust than GameLink (but not as fast as the MUX).

Conceptually, you could have four computers; the COMMAND line on any of them would hit the INTERRUPT line on the XEGS, but also be mapped to a line into one of the joystick ports - that way the XEGS would know which computer was requesting the data. Each of the four could in theory have different drive mappings.


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 Post subject:
PostPosted: Wed Apr 16, 2008 7:40 pm 

Joined: Sat Sep 13, 2003 12:21 am
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It is 8k blocks unfortunately. I don't think the Maxflash cartridge is very well suited for this application (unfortunately you'd need to read the 8k block into RAM somewhere, replace your 128byte disk sector and then flash the 8k block back....yuck.) Edit: actually it's 16k, thanks for the correction, Wrathchild!

Cas, simply reading the cartridge memory as a "pretend" disk is already implemented in the maxflash tools, and the source is all there to look at. Is that what you meant?

Steve can say more, I'm sure.


Last edited by Shawn Jefferson on Sun Apr 20, 2008 12:16 pm, edited 1 time in total.


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 Post subject:
PostPosted: Wed Apr 16, 2008 8:14 pm 

Joined: Sun Dec 04, 2005 10:52 pm
Posts: 13
Location: Ottawa, Ontario
Well, SDX 4.41 does support larger block sizes, but 8k blocks would be a wee bit ridiculous on an 8-bit...

I'll look to other methods of storage to implement a SIO network- like maybe an internal MyIDE on the server...


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 Post subject:
PostPosted: Thu Apr 17, 2008 7:21 am 
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Joined: Mon Jan 12, 2004 5:01 pm
Posts: 83
Location: Reading UK
The erase block sizes are 16K on the 1Mbit cart (8*16K=128K) and 64k for the 8Mbit cart (which has 2*4Mbit chips and so 8*64K=512K) so this is not really practical. There are some chips with a 256 byte block size, e.g. AT29C040 http://www.atmel.com/dyn/products/product_card.asp?family_id=624&family_name=Parallel+Flash&part_id=1806 but presumably that might require some rewrite of the GAL?

Regards,
Mark


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 Post subject:
PostPosted: Thu Apr 17, 2008 7:39 pm 
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If the PLCC pinout is the same it should work with just new software to program it. Assuming it does not need a separate programming voltage.

Steve


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 Post subject:
PostPosted: Fri Apr 18, 2008 5:45 pm 
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Joined: Mon Jan 12, 2004 5:01 pm
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Location: Reading UK
Hi Steve,

I've ordered some AT29C010A-12JC chips to try this out on.
These are 1Mbit in size and have a very useful 128 byte sector size :)

Actually it probably wouldn't be too tricky to update the emulator to support this chip too :lol:

Regards,
Mark


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 Post subject:
PostPosted: Fri Apr 18, 2008 9:43 pm 
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Looks very similar to the F series program erase system, just with more sectors. I'm very interested to hear how it works for you.

Steve


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