Re: How to program a FlashRAM on a Commodore

From: Marko Mäkelä <>
Date: Sun, 5 May 2013 21:59:44 +0300
Message-ID: <20130505185944.GB4175@x220>
On Sun, May 05, 2013 at 12:18:25PM +0200, Nicolas Welte wrote:
>I just looked, Marko Mäkelä wrote a VIC20 flash software for my 
>Some documentation on my hardware can be found here: 
>Maybe you can also look at the Final Expansion 3, it uses AM29F040 on 
>the VIC20!

My Vic Flash Plugin uses an 
Am29F032B (probably the largest 5-volt flash chip, 4 megabytes). I think 
that nowadays, it would make more sense to use a tiny flash chip for 
booting, and then load the rest from an SD card.

Inside the file you can 
find the source code for the programmer, vfp/flash4.s or 
vfp/flash4file.s. The latter version reads the flash image from a file 
(such as from an SD card connected to the sd2iec). I successfully tested 
it with a compressed image that was somewhere around 2MB.

Note that the Vic Flash Plugin swaps the address lines A0 and A1 in 
order to simplify the circuit board layout. That is why the magic 
addresses are defined like this:

f000	= flash			; flash address 0
f001	= flash + 2		; flash address 1
f555	= flash + $556		; flash address $555
f2aa	= flash + $2a9		; flash address $2aa

Best regards,


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Received on 2013-05-05 20:00:03

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