NRF9160 Flash Endurance

[Thomas]

Hi,

I am aware that when the the modem is powered down with AT+CFUN=0, GPS data such as the ephemeris is saved to flash. What endurance does this flash have? How many times can we turn the GPS off before the flash reaches its limit? 

I have the same question with reference to parameters stored in flash (such as setting the permanent band lock). I also would like to know if you set something like the bandlock does the modem check to see if they are different before storing it to flash? Or do we need to check ourselves to prevent unnecessary flash writes.

Kind regards,

Thomas

[Martin Lesund]

Hi Thomas,

Ref

So turning the GPS on/OFF should not "tear down" the Flash endurance.
Only issuing the AT+CFUN=0 
- When commanding the device to power off, wait for OK to make sure that Non-volatile Memory (NVM) has been updated.

So instead you can use AT+CFUN=4, which will not update the NVM. 
However if your network has support for PSM and/or eDRX it is recommended to use that, to gain the power saving features from not needing to attach/de-attach to the network each time you are using the GPS, plus the speed benefit.

When it comes to the second question, only after the AT+CFUN=0 will it store the settings you have set in the XBANDLOCK to the NVM.

Best regards,

Martin  L.

[Thomas]

Thanks Martin, 

To confirm, we only get 10,000 AT+CFUN=0s?

Kind regards,

Thomas

[Martin Lesund]

Hi Thomas, 
That depends on how much parameters you may have changed.
If you issue AT+CFUN=0 and the parameters you have set is the same that is already in the NVS it will not overwrite the Flash with the same data, so it will not use a "write cycle" for that.

We guarantee the Flash endurance up to 10,000, but it could still work as intended after even if that is out of spec.

[Thomas]

Ok great, that’s good to know. Thanks Martin.