Re: [avrdude-dev] AVRDUDE and AT17LV

[Brian Dean]

On Mon, Sep 06, 2004 at 10:04:08PM +0200, Rudolf Matousek wrote:

> Well, and now I don't really know what else. The memory is using I2C 
> interface. I.e. each block write starts with a start bit, then it 
> continues by writing a sequence of bytes and it is finished by a stop 
> bit. Each write operation must be acknowledged by a low value on data 
> signal. The byte sequence is cmd, addr1, addr2, addr3, data1, ..., dataN.

I don't think you can make this work with AVRDUDE as it is geared
around SPI interface communications.  The signal lines SCK, MOSI, MISO
are "SPI" signals and are controlled as such.

Not to say it could not be done, just that AVRDUDE is probably not the
best program to use as a basis.  I think what you want is something
that can program I2C memory.  Sounds like you could make a little AVR
board that has a UART to interface to your PC, and an I2C interface to
talk to your I2C memory part.  With a little programming on either
side, you can send the data to be written out your serial port to the
AVR chip which can then buffer it and send it on off to the device you
wish to program using its the I2C interface.  I have code examples on
my web site for the ATmega128 that can read and write to serial
EEPROMs using the standard 24Cxxx I2C protocol.  Not sure if the
device you are programming uses that method or not, but the code there
might be helpful as a starting point.

      http://www.bdmicro.com/code/

Alternatively, there's bound to be some code and schematics out there
to interface the PC parallel port to an I2C bus.  It shouldn't take
much - maybe a buffer chip and a few resistors to use for pull-ups on
the I2C bus.  After that it's just a small matter of the software :-)

-Brian
-- 
Brian Dean
http://www.bdmicro.com/