Storing user data to flash and avoiding overwrite on application update

RE: Storing user data to flash and avoiding overwrite on application update

lara — Sat, 07 Dec 2024 09:27:13 GMT

can you provide me the simple example code for nvs settings? as iam kept on facing errors,,somewhere i collapsed everything

RE: Storing user data to flash and avoiding overwrite on application update

Anthony W — Wed, 01 Feb 2023 19:51:04 GMT

Ahhh okay this was the problem. I started from the NVS demo and didn't look at the CMake config. Now it works perfectly, thank you!

RE: Storing user data to flash and avoiding overwrite on application update

Hung Bui — Mon, 30 Jan 2023 14:29:16 GMT

Hi again,
It worth mentioning that if you have a v3 chip that has upgraded APPROTECT on both hardware and software and if in the software you don't deliberately disable APPROTECT , you will need to recover the chip (eraes all) every time you flash new firmware to it. In VS Code you will most likely receive a popup saying that the chip need to be recovered.

Please double check.

RE: Storing user data to flash and avoiding overwrite on application update

Hung Bui — Mon, 30 Jan 2023 14:24:42 GMT

Hi Anthony,

Which sample are you testing with ?

By default if you click on the flash icon with one arrow (Flash only), it will only erase the sectors occupied by the new application, not the whole flash. So the NVS storage area shouldn't be affected.

If you click on the flash icon with 2 arrows (Erase and Flash) it will erase the whole flash and then flash the application image.

However if you use the NVS, there is a setting in CmakeLists.txt that apply erase in both cases:

# SPDX-License-Identifier: Apache-2.0

cmake_minimum_required(VERSION 3.20.0)

macro(app_set_runner_args)
  board_runner_args(dfu-util "--dfuse-modifiers=force:mass-erase")
  board_runner_args(pyocd "--erase")
  board_runner_args(nrfjprog "--erase")
endmacro()

find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
project(nvs)


target_sources(app PRIVATE src/main.c)
target_include_directories(app PRIVATE ${ZEPHYR_BASE}/subsys/fs/nvs)

If you remove the macro that do --erase it should work fine.

You can also test using nrfjprog.exe command line tool. Do a --sectorerase when programming will not make the NVS data to be erased.

RE: Storing user data to flash and avoiding overwrite on application update

Mike Austin (LPI) — Mon, 30 Jan 2023 01:53:51 GMT

I've got NVS in my application, and can maintain values I have stored from one DFU to the next. I can even get these to carry over from one application (my "factory" code) to a completely different application (my "operational" code) without issues. I'm also using VSC and nRF Connect v2.2.0.

Two things that come to mind (but I may be totally on the wrong track here):

1. Are you doing a plain flash (Flash to Board) and not an erase + flash ( Erase and Flash to Board) from within VSC?

2. I have fixed partitions for my flash storage (I have settings_storage for BLE, etc and user_storage for my data). Not sure if having fixed partitions helps to ensure the data carries across reliably

Mike