[coreboot] AMD690GM-M2

Peter Stuge peter at stuge.se
Thu Oct 9 18:40:31 CEST 2008

Josh wrote:
> > Good, the chip is supported by flashrom.
> I'm having troubling finding a place to buy a W39V040B chip in the
> US. Looks like avnet.com is a good place to buy an alternative
> chip, but I can't to find any information on how to pick a chip
> that is compatible.  What criteria do I need to look at when
> picking out a different chip.

There are a few parameters that have to match;

* Package, usually one of:
 * DIP32 (for parallel)
 * PLCC32 (for parallel and LPC and FWH)
 * TSOP32 14mm (for parallel and LPC)
 * TSOP32 20mm (for parallel and LPC)
 * SO8 200mil (for SPI)
 * SO8 150mil (for SPI)
 * DIP8 (for SPI)
* Protocol, one of:
 * ISA (parallel)
 * LPC (serial 4-bit)
 * FWH (serial 4-bit)
 * SPI (serial 1-bit)
* Signalling
 * 5V (for parallel)
 * 3.3V (for LPC and FWH and SPI)

W39V040B is LPC, and available in PLCC32 and TSOP32. PLCC is much
more common.

Any other LPC PLCC flash chip will work.

> While I'm at it, I'd like to go with a bigger chip unless there is
> a reason not to.

As others mentioned this depends on how the (in this case LPC) bus
master can be configured. The southbridge needs to decode (bus
terminology for route or connect) the entire memory area that would
be occupied by a larger flash chip onto the LPC bus where the chip
is connected.

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