how to over write data in same offset into internal flash on zephyr

RE: how to over write data in same offset into internal flash on zephyr

ChiragBhavsar — Wed, 06 Nov 2024 11:49:40 GMT

Hi, thanks for your support! Using NVS, I was able to successfully overwrite the data.

RE: how to over write data in same offset into internal flash on zephyr

Sigurd — Tue, 05 Nov 2024 23:55:10 GMT

Hi!

You would need to erase the entire page, on nRF5340 app core each page is 4 kB.

[quote user="ChiragBhavsar"]Additionally, could you provide an example of using NVS (Non-Volatile Storage) for storing data?[/quote]

See this sample: https://github.com/zephyrproject-rtos/zephyr/tree/main/samples/subsys/nvs

RE: how to over write data in same offset into internal flash on zephyr

ChiragBhavsar — Tue, 05 Nov 2024 15:43:32 GMT

Hi,

I am able to erase the flash using flash_erase(flash_dev, TEST_PARTITION_OFFSET, FLASH_PAGE_SIZE). However, when I use flash_erase(flash_dev, offset, sizeof(uint32_t)), the flash does not erase as expected. What could be the reason behind this?

After erasing the flash, I write data (e.g., 1234) and can successfully read it back. However, when I write new data (e.g., 1122) to the same offset, I still read back the original value (1234). Is there a method to properly overwrite data at the same offset?

Additionally, could you provide an example of using NVS (Non-Volatile Storage) for storing data?

RE: how to over write data in same offset into internal flash on zephyr

Sigurd — Tue, 05 Nov 2024 13:31:50 GMT

Hi!

A flash write can only flip bits from '1' to '0'. When erasing a flash page, all zeroes are reset to '1'. Therefore, it is necessary to erase the flash before updating existing data. I suggest using e.g. nvs for your use-case. https://docs.zephyrproject.org/latest/services/storage/nvs/nvs.html