Ram retention - which regions to retain on nrf52840

[Michal]

Hi, 

I have spend some hard time trying to figure how to work with RAM retention. Looks like it is working for me now, but now I retain all available memory. How much energy this will consume additionaly in system off ? Is it 20nA * 15 * 9 = 2,7 uA ? I would like to make it more efficient to enable only those regions that I really need, how do I do that? I found this nice description in this ticket - https://devzone.nordicsemi.com/f/nordic-q-a/18686/ram-retention-nrf52 - but that was for nrf52 and I use nrf52840.

Michal

[Marjeris Romero]

Hi,

Numbers from the product specification:

In System OFF, full 256kB RAM retention, wake on reset -> 1.86uA

For RAM retention you can estimate power consumption to ~20nA per block,4kB per block.

Best regards,

Marjeris