[LinuxBIOS] Cheap self-built BIOS saviour for 8M/16M parts?

Carl-Daniel Hailfinger c-d.hailfinger.devel.2006 at gmx.net
Mon Feb 26 03:10:40 CET 2007


after combing through the SST data sheets for the
* SST49LF008A
* SST49LF080A
* SST49LF016C
* SST49LF160C
parts, I am fairly sure I found a procedure to have multiple
flash parts attached at the same time which should just work.

Simply use two chips of the same model, connect all of their
pins except ID[0], wire ID[0] of each of the chips to one side
of an intermediate switch which is connected to Vcc and GND
on the other side. The intermediate switch makes sure exactly
one chip has Vcc at ID[0] and the other one has GND at ID[0].
The switch with GND on ID[0] is the one selected. However,
you need to drive the RST# pin of both chips to GND for 1µs
whenever you want them to change roles during system operation.

So you'll need:
* 2 identical flash chips
* intermediate switch (can be hardware)
* a way to drive RST# to GND without shorting the board
* serious soldering skills to solder two chips to each other

Sounds nice?
Surely there's a catch. It can't be that easy, right? Tell me!


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