Why is the data I write through the QSPI interface different from the data actually captured on the line?

RE: Why is the data I write through the QSPI interface different from the data actually captured on the line?

Simonr — Tue, 27 May 2025 09:37:26 GMT

I just wanted to chime in regarding the QSPI peripheral here. It is indeed only designed for communication with NOR flash devices, but there shouldn't be anything specific limiting it from being used otherwise, but you will be on your own regarding implementation, and we here at Nordic can't guarantee it will work since it's not tested or designed for it.

With regards to the issues you're seeing, there are a few erratas that affect the QSPI peripheral on the nRF5340 that you should be aware of when using it, so please check out the errata list here, more specifically numbers 43, 99, 121, 133, 136 and 159.

Best regards,

Simon

RE: Why is the data I write through the QSPI interface different from the data actually captured on the line?

Turbo J — Tue, 27 May 2025 07:55:15 GMT

Read the QSPI paragraph in the PS. That peripherial has very strict hardware limits.

RE: Why is the data I write through the QSPI interface different from the data actually captured on the line?

duxinglang — Tue, 27 May 2025 07:45:25 GMT

oh my god! Are you saying that even if we connect other hardware peripherals to the default QSPI pin or write the correct drivers in the application code, instruction and data transmission will still be limited by the QSPI controller or NRFX code of 5340?

RE: Why is the data I write through the QSPI interface different from the data actually captured on the line?

Turbo J — Tue, 27 May 2025 07:33:14 GMT

Reason is that the QSPI peripherial does not support anything other than some NOR flash chips that it is tailored for.

Read the PS for details - you will likely need to change the design.

Scope picture looks like a "read status" (RDSR) opcode to me. That one might be baked into either the hardware or the NRFX code - which one I am not sure right now. Its been a while since I played with QSPI here.

Note that the scope QSPI decoder looks like its not set up correctly for decoding the opcode.