Macronix MX25R1635F External Flash Issue

joebambino

Hi Everyone,
After beginning development on nRF9160 Feather, we have developed our own system using the nRF9160 and the nRF52840 and Zephyr/Nordic SDK. We are having a bear of a time getting the MX25R1635F external flash to work with our the QSPI driver. The strange thing is, with our same code, the MX25R6435F on the nRF52840-DK works just fine. Has anyone ran into this? Anything obvious we could be missing?

NCS version 2.0.0
Zephyr version 3.0

Thanks,
Joe

jaredwolff

@joebambino you’ll probably need to provide more context. In general you want to make sure that the definition of your external flash part matches your hardware (i.e. all pins are mapped correctly) I haven’t played yet with NCS 2.0.0 but I don’t think they changed much vs v1.9.x/v1.8.x/v1.7.x.

joebambino

Hi @jaredwolff thanks for the reply. We finally figured out the issue. It turns out that one of the pins we were using for QSPI was a NFCT pin. We had thought that on the nRF52840, those pins defaulted to GPIO and that you had to turn on the NFC functionality. The fact of the matter is that it is the other way around. The pins default to being NFCT and they need to be changed to GPIOs by invoking CONFIG_NFCT_PINS_AS_GPIOS. So even though we had proj.cof, board overlay, GPIO characteristics, device tree, etc. correct, it wasn’t actually being used as QSPI.

jaredwolff

Ahh yep that will always get you. The same thing goes for P0.18 (Reset) too. There’s a built in pull-up that can’t be deactivated.