Multiple QSPI devices with nRF5340 (e.g. Flash and Wifi) - can other pins than high-speed QSPI dedicated P0.13-P0.18 used for additional Chip Selects?

RE: Multiple QSPI devices with nRF5340 (e.g. Flash and Wifi) - can other pins than high-speed QSPI dedicated P0.13-P0.18 used for additional Chip Selects?

Jared — Thu, 02 Mar 2023 08:04:25 GMT

Hi Michael,

[quote user="puz_md"]

if I understand correctly, this means the QSPI can only be used with one high speed interface device by design, because even if you disable the QSPI and re-configure PSEL.CSN, there is only one pin available that can handle the data rates reliably.

[/quote]

Correct,

[quote user="puz_md"] guess this is why you connect the QSPI flash on the nRF7002DK, which is the same as the QSPI Flahs on the nRF5340DK, here only via standard SPI, right? (Does the XIP also work with standard SPI, by the way?)[/quote]

Yes, this is probably why. XiP only works with QSPI.

[quote user="puz_md"]Is there any information available if the QSPI will work reliably with different PSEL.CSN for lower data rates? Quad data lines might still be better than single bit SPI, even if it might be necessary to disable and re-enable the QSPI module each time the target device is switched. Would be nice if we could document this information in this ticket, for future reference. (Adding it to the Product Specification would also be nice.)[/quote]

No, we don't have any information on that since it's outside of the product spec. The product specification already mentions that only the dedicated pins should be used for QSPI.

regards

Jared

RE: Multiple QSPI devices with nRF5340 (e.g. Flash and Wifi) - can other pins than high-speed QSPI dedicated P0.13-P0.18 used for additional Chip Selects?

puz_md — Tue, 28 Feb 2023 19:32:49 GMT

Hi Jared,

I guess this is why you connect the QSPI flash on the nRF7002DK, which is the same as the QSPI Flahs on the nRF5340DK, here only via standard SPI, right? (Does the XIP also work with standard SPI, by the way?)

Is there any information available if the QSPI will work reliably with different PSEL.CSN for lower data rates? Quad data lines might still be better than single bit SPI, even if it might be necessary to disable and re-enable the QSPI module each time the target device is switched. Would be nice if we could document this information in this ticket, for future reference. (Adding it to the Product Specification would also be nice.)

Suggestion for future devices: Just add some automatic wait states for slower IO pins, if this doesn't add too much complexity for the QSPI module.

Best regards,

Michael

RE: Multiple QSPI devices with nRF5340 (e.g. Flash and Wifi) - can other pins than high-speed QSPI dedicated P0.13-P0.18 used for additional Chip Selects?

Jared — Tue, 28 Feb 2023 15:41:54 GMT

Hi Michael,

Disabling PSEL and manually setting chip select on IOs will not work. The QSPI peripheral needs to control the chip select. In addition using other pins then the dedicates ones for CS is outside of spec, and therefore not tested. We therefore can't guarantee that this will work, and we don't recommend it all.

regards

Jared

RE: Multiple QSPI devices with nRF5340 (e.g. Flash and Wifi) - can other pins than high-speed QSPI dedicated P0.13-P0.18 used for additional Chip Selects?

puz_md — Tue, 07 Feb 2023 15:34:16 GMT

Thanks! i'm not in a hurry, so please take your time.

RE: Multiple QSPI devices with nRF5340 (e.g. Flash and Wifi) - can other pins than high-speed QSPI dedicated P0.13-P0.18 used for additional Chip Selects?

Jared — Tue, 07 Feb 2023 14:56:23 GMT

Hi,

I just wanted to let you know that we're still working on getting information on this from our HW team.

Thank you for your patience,

regards

Jared

RE: Multiple QSPI devices with nRF5340 (e.g. Flash and Wifi) - can other pins than high-speed QSPI dedicated P0.13-P0.18 used for additional Chip Selects?

Jared — Wed, 01 Feb 2023 13:43:17 GMT

Hi Michael,

I have to ask our HW designers about this,

I'll be back with more,

regards

Jared