Can't get flash memory to work (Winbond 25Q128JVSM)

[mattkuebrich]

I've soldered in a flash memory chip to my Teensy 4.1, but it doesn't seem to be working. When I run the "EraseEverything" sketch from the SerialFlash library, I get the error "Unable to access SPI Flash chip". I've reflowed the solder quite a few times so I think it's making a good connection.

Maybe I bought the wrong chip. It's a Winbond 25Q128JVSM. I also don't have anything soldered to the PSRAM pads (the smaller ones to the left of the larger flash mem pads)... I don't need both for the flash memory to work correct?

Thanks!

 

[mjs513]

The pads on the bottom of the Teensy 4.1 for PSRAM and flash both use the QSPI bus on the Teensy. From the production page:

QSPI Memory Expansion
Teensy 4.1 has 2 locations to add 8 pin QSPI memory chips. Both locations support 8MB PSRAM chips. If only 1 PSRAM chip is used, it must be soldered to the smaller pads. The larger pads may be used with certain flash memory chips supported by the LittleFS library.

The SerialFlash library is meant for flash memory attached to a SPI buss such as SPI, SPI1 etc:

SerialFlash provides low-latency, high performance access to SPI Flash memory with a filesystem-like interface

So to make a long story short to access the winbond flash on the bottom of the Teensy 4.1 you have to use LittleFS which is an included library in Teensyduino.