RE: issue about QSPI SCK

Kenneth — Tue, 30 Aug 2022 12:31:03 GMT

[quote user=""]

The following picture is the logic analyzer get SB11's waveform.

[/quote]

It looks like you have setup to sample 5MHz, this is too slow to slow for QSPI in general, and for instance will make the clock signal to look with an inapproprioate duty cycle, but also in this specific case you likely will also miss clocks. I suggest to sample at for instance >50-100MHz.

[quote user=""]

Then I use the oscilloscope to get the waveform of SCK pin, I‘m more confused, the waveform isn't a square wave.

[/quote]

If you haven't already make sure to configure high drive (see NRF_GPIO->PIN_CNF[]) register on the pins used for QSPI, this should overall make nRF52840 be able to drive the pins better. Though have in mind that if you add probes on the QSPI pins, this will cause additional capacitance on the pins that may cause the issue you see here.

Best regards,
Kenneth