QSPI with different configurations

RE: QSPI with different configurations

Turbo J — Fri, 08 May 2020 11:50:17 GMT

Note that you can still use SPIM with your RAM chip, as it support traditional SPI. SPIM3 on nrf52840 has some issues with dma memory (see errata), but can be used for fast SPI communication.

RE: QSPI with different configurations

Simonr — Fri, 08 May 2020 11:37:12 GMT

Thank you for your suggestion! We're aware of this and it is up for discussion internally.

Best regards,

Simon

RE: QSPI with different configurations

Den — Thu, 07 May 2020 20:47:06 GMT

Thanks very much for the clarification Turbo.

I am deeply disappointed by this. QSPI should have been freely configurable just like other peripherals SPI, UART etc. It's a shame that I have not figured this out before choosing the SRAM. Totally so naive of me, I have never used QSPI before.

Nordic Engineers please take this as an improvement suggestion for newer models. You are immensely limiting our choices of memories this way.

Regards,

Denin

RE: QSPI with different configurations

Turbo J — Thu, 07 May 2020 20:02:48 GMT

[quote userid="75000" url="~/f/nordic-q-a/61154/qspi-with-different-configurations"]Moreover, we have future plans of using QSPI with SD card. [/quote]

Not going to happen.

SPI support in SD cards is single bit only - works fine with SPI and SPIM peripherials.

The 4 bit SD protocol is different and requires hardware support. Some "bigger" µCs have that but nothing in NordicSemi chips.

[quote userid="75000" url="~/f/nordic-q-a/61154/qspi-with-different-configurations"]However some commands are different[/quote]

That also precludes QPSI peripherial usage. The magic command numbers are hard coded into the peripherial AFAIK and should be documented in the PS.

Also, external RAM is rather slow. Almost always better to use a bigger microcontroller instead, like the upcoming NRF53's.