NRF52 Non volatile Memory

[Oussama]

Hello, 

Is there any way i can transmit information from the bootloader to another application using a non volatile memory or non volatile register free for use. 

I know about the nrf fstorage module, but it seems that u can't allocate less then a page size, which is 4 kBytes. The information i am trying to transmit is only 4 bytes so 4kbytes is too much.

Thank you for your help.

[Susheel Nuguru]

There are some UICR->CUSTOMER registers that you can use to save small amount of persistant data.

The problem is that once written to these registers, the data cannot be erased without erasing the whole chip. So if you want to transmit 4 bytes of dynamically changing data frequently, this might not suit you.

[Oussama]

Thank you for the answer. But my data changes dynamically and more or less frequently. So erasing the chip is not an option. 

Is there a way i can erase the UICR Customer register without erasing anything else ?

[Susheel Nuguru]

If your data is changing dynamically and more or less frequently, then you cannot write it to the same address of the flash without erasing the flash block. And the smallest erase unit is a page which is 4KB. So I do not see that you can remove the dependency of minimal 4KB size anyway to have erase capabilities.