Save a single byte onn flash is it possible?

[Mufasa1]

Hi all,

I am trying to save an UART variable I am receiving. My case is very similar to the example Flash Write Example, but I would write few bytes instead of the whole flash page it is possible?

My application uses a nRF52 and requires SDk13

Thanks

[endnode]

Sure, you can write single word (32 bits) into the flash. Just make sure it's "empty" (= 0xFFFFFFFF aka all bits set to 1) before writing otherwise your write will probably result into wrong data (flash technology cannot change 0 bits to 1 unless you erase whole page). This is one of main added values of all the pstorage/fstorage/FDS libraries, they should manage page erase, backup etc. so you do just "logical" operations and leave dealing with "physical" addressing to lower layer functions and module logic.

[HeS]

Its possible to write single byte (bit:) into the flash. Rest of bytes (bits) in 32-bit word must be set to 0xFF.

[endnode]

The write command must contain 32 bits, that what I was saying. Sure you can "change" only single bit which will effectively mean that you will "write" single bit.

[Mufasa1]

I was using the UICR for the task, but I would go into troubles If I want edit the data your options are FSD?

[endnode]

What do you mean by "I was using the UICR for the task"? That is NVM region but with specific restrictions, you can basically just write one-time into few registers. For that classic routine should be used (as for any direct work with registers!): read out full 32-bit value, mask the bits you are modifying merge it with new value you want to push in. Then simply set the register (pointer to register 32-bit address in continuous address space of the chip) to new value and you are done. Or you meant UART not UICR? I'm confused.