[coreboot] SPI flashing

[Andrew Morgan]

On 06/07/11 12:23, Andreas Galauner wrote:
> Also the pinout is kind of "weird":
> 1	#CS
> 2	#CS
> 3	SI
> 4	NC
> 5	SO
> 6	VCC
> 7	SCK
> 8	GND
>
> Why is CS# connected to two pins? The resistance between those two pins
> is 1 Ohm, so they are connected directly. Interestingly the are
> connected through a 0 Ohm resistor. Any ideas on that?

I don't know the answer, I'm just having a guess here.
It could be that one of the #CS pins is connected to the flash chip, and 
the other is connected to the SPI controller (or whatever you call the 
thing an SPI flash chip is connected to on a computer motherboard). If 
that were the case then if the 0Ω link wasn't there you would be able to 
connect an SPI chip and a switch to that port. The switch would either 
short pins 1 and 2, to select the internal flash chip, or would connect 
whichever #CS pin is connected to the SPI controller to the #CS pin on 
the external SPI flash chip in order to select that chip instead.

Does that sound like a possibility?

-- 

Andrew.