[flashrom] External programmers
fritzlists at gmail.com
Wed May 5 02:26:39 CEST 2010
Carl-Daniel Hailfinger wrote:
> I'm trying to find out which external programmers should be supported next.
> 1. There was talk of an AVR-based new programmer using the serprog
> protocol on IRC by someone with the nick "coldelectrons", but I have no
> idea if he/she is reading this mail. IMHO more hardware using the
> serprog protocol is always a good idea.
That would be me, and yes, I am.
I had a Willem clone at one time, but the software I received with it is
far from current - and then I had to try and figure out which
variant/version I had so I could try to download the right version....
I no longer have the Willem in whole form, just as I no longer use
Windows, which is why I'm trying to make my own.
I'm using an Arduino Mega to speak the 'serprog' protocol, and to
bitbang a parallel bus to a DIP32 socket. The atmega1280 on the Mega
has the capability of interfacing to an external SRAM, but I haven't had
much luck in making that work in a breadboarding environment. After all
the IO used for the parallel bus, there is still enough IO left over
(and dedicated functions) for rs232, SPI, and i2c.
My current schematic only works for 5V-only chips.
My problem thus far is that while I can read a chip and dump it to a
file, I'm unable to detect or write to a chip. From what I can tell,
something doesn't jive between normal AM29F040 probing and the operation
of a serprog programmer. For one thing, you need to throw certain
address/values at a 29F' and detect a response...while the serprog
protocol buffers all writes to an operation buffer. I don't think the
probe routine ever 'executes' the buffer. I've only been looking over
the code for maybe 2 days, so I'm far from expert on it.
Even as I received this email, I've been dicing up flashrom code into a
python script that will hopefully talk to my ad-hoc programmer and flash
my darn AM29F040 for me.
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