[OLPC-devel] olpc flash program.

[Richard Smith]

> Corrupt flash seems the most likely reason unless you were
> experiencing some flakiness before it became unusable. Can't it be
> reprogrammed through JTAG? What equipment is needed to reprogram the
> flash?
>
> Having written flash drivers before, I'd like to experiment with your
> driver, but I need to know I can recover my own board if (when)
> necessary.

I was discussing this with Tom earlier in a off list thread.  And I'm
not sure the device is  ever going to be _fully_ recoverable by jtag.
The serial rom is  SPI and so is not connected to the JTAG chain.  You
have to talk to the EC which does the SPI to the rom.  So if you trash
the EC code.  I think you are toast.

The wiki says that CN20 is used for serial flash programming but that
it needs a special fixture.  I'm guessing that you can drive SPI
directly to the part via that connector.  The simple bit banger
parallel port interface listed on the JTAG page should be able to
drive that but it may need a level shifter depending on what Vcc the
part runs at.

If we can get the pinout of CN20 and how all thats wired up perhaps we
can put together a simple flash recovery hardware/software suite.

-- 
Richard A. Smith