Re: [flashrom] Some troubles connecting a W25X40ALSNIG flash chip to raspberry pi (v3 model B) - flashrom

6 Mar 2018


      Hi,
On 06.03.2018 00:20, Jesse Li wrote:
...
Hey,
I'm trying to read from and flash to a W25X40ALSNIG [0] that's still
mounted to its hard drive PCB. Following the table from the raspberry pi
wiki page [1], and assuming the raspberry pi pin numbers it mentions are
physical pin numbers (and not the pi's strange GPIO numbering scheme) I
connected the legs of the flash chip to the raspberry pi's GPIO pins.
However, when the two are attached, the pi won't boot (it'll show the three
raspberries in the corner, then it shuts off). I've isolated this to the
VCC (connected to header 17, 3v3) and GND (connected to header 25, GND) ,
where having all of the legs of the flash chip detached from the pi except
for those two will reproduce my problem (I hope testing that didn't
actually kill the chip). What am I missing?
the circuitry of your hard drive is most likely not prepared for powe-
ring the flash chip directly at its VCC pin. You probably power all 3V3
parts on that PCB which is too much for your RPi's PSU / voltage conver-
ter.
Killing the SPI flash is unlikely. I can't say the same about other
chips on the board, though. Reading the flash while the hard drive is
up and running, probably also isn't a good idea. You could desolder the
flash chip, or try a stronger PSU, both ways have chances to break some-
thing.
Nico