Hi,
welcome to flashprog :)
Thank you.
On 5/26/26 19:15, tctl5p9ik7vh--- via Flashprog wrote:
Hello. I have a few questions about reading spi using raspberry pi with flashprog. I've had some problems so far. First I would like to know if the winbond 25q256jvem chip is supported. I see W25Q256JV_M is a supported chip. Does that V_M cover the VEM variant?
Yes, it's supported. The _ is meant to be a placeholder. The E in VEM only signifies the chip package. Internally, they are the same.
Also I would like to know what is the recommended advice for pins 3 (WP/IO2) and 7 (HOLD/IO3)? Should they be spliced into pin 8 or floating when reading a quad speed chip?
It depends on the overall setup. If the chip is soldered to a mainboard for instance, these pins would be connected already. If you have a plain chip connected to your RPi, you should always connect all pins (doesn't matter if it's a quad chip, quad is enabled or not). You can put a resistor between these pins and VCC for safety, something < 100kOhm should work.
That's what I thought. I just wanted to be sure since it isn't reading. The chip is soldered to the mainboard.
If the chip is on a mainboard, problems are likely related to the circuitry on the board. Best is to look into documentation for the particular board or its schematics if you can find them.
This is the mainboard here https://www.aliexpress.us/item/3256811444835229.html I'm still looking for a datasheet. Do you have any suggestion what to look for in trying to track down the problem?
On 5/27/26 16:40, tctl5p9ik7vh--- via Flashprog wrote:
If the chip is on a mainboard, problems are likely related to the circuitry on the board. Best is to look into documentation for the particular board or its schematics if you can find them.
This is the mainboard here https://www.aliexpress.us/item/3256811444835229.html
I'm still looking for a datasheet. Do you have any suggestion what to look for in trying to track down the problem?
Most common issue is power supply. When a board isn't designed to be flashed this way, voltage may leak to other components on the mainboard. Hence board-specific documentation is so important. Measuring voltage when trying to access the flash may give a clue. Without documentation it's best not to apply voltage via the flash programmer (RPi in your case), in case you were trying this. Better is to use the board's regular power supply and making sure that it doesn't boot (i.e. stays in a soft-off / S5 state). And *not* connec- ting VCC to pin8. Again, measuring voltage at the flash chip. That it's a WSON chip also doesn't make things easy. Did you solder something and can confirm connectivity? or how do you connect to the flash chip? Nico
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Nico Huber -
tctl5p9ik7vh＠opayq.com