nRF91 PSRAM support

[Otso Jousimaa]

Hello,

We're needing a lot more RAM than what nRF91 has, does current nRF Connect SDK support parallel PSRAM on Zephyr somehow or is the development on a roadmap?

[Hakon]

Hello,

I don't think there is support for PSRAM, but I will need to confirm this. I will report back in a short while.

[Otso Jousimaa]

Thanks, if PSRAM cannot be supported maybe there would be another way of reaching our goal. 

We need to send a stream of data to the Cloud. Data is coming in at roughly 100 kBps for at least 5 seconds, so 512 kB to 1 MB fast enough storage would be needed. What kind of approaches we could use here? Write endurance has to be at least 10 000 cycles, so some flash might also work for us if it can keep up with the data rate. 

The application should work with NB-IoT and LTE-M so streaming data as it comes directly is probably not feasible. 

[Hakon]

There is no external memory bus on the nrf9160, so PSRAM can't be supported unfortunately. You could try using an SPI interfaced external RAM instead, if you need more memory than what the nrf9160 can provide.