Memfault Zephyr + STM32H7B3I_DK Example

This sample app showcases Memfault functionality on the stm32h7b3i_dk board.

Getting Started

The Memfault Zephyr integration guide is an excellent reference, and documents how the Memfault SDK was added to the base example app:

https://docs.memfault.com/docs/mcu/zephyr-guide

To try out this example app:

1. Set up the Zephyr prerequisites: https://docs.zephyrproject.org/latest/develop/getting_started/index.html

2. Create a zephyr workspace and set it up with this project:

   mkdir zephyr-workspace
   cd zephyr-workspace
   west init -m https://github.com/memfault/zephyr-stm32h7b0-example
   west update

3. Build the example app:

   west build --sysbuild --board stm32h7b3i_dk --pristine=always zephyr-stm32h7b0-example

   --sysbuild will build the MCUboot image as well, which will also get flashed in the following step. To run sysbuild by default, you can configure your workspace with west config --local build.sysbuild True.

4. Flash the example app:

    west flash

5. Open a serial console and interact with the sample app shell. For example using PySerial:

   # select the correct serial port for your system
   pyserial-miniterm --raw /dev/serial/by-id/usb-STMicroelectronics_STLINK-V3_002000353331510933323639-if02 115200
   
   uart:~$ mflt get_device_info
   [00:00:03.449,000] <inf> mflt: S/N: 373535343430510d00410045
   [00:00:03.455,000] <inf> mflt: SW type: app
   [00:00:03.460,000] <inf> mflt: SW version: 0.0.1+1e097ff
   [00:00:03.465,000] <inf> mflt: HW version: stm32h7b3i_dk

Note about MCUboot + Sysbuild

This example application uses Zephyr's Sysbuild feature to build both the bootloader and application together.

To enable MCUboot, this guide was followed:

https://docs.mcuboot.com/readme-zephyr

The following steps were taken:

1. add a sysbuild.conf file with SB_CONFIG_BOOTLOADER_MCUBOOT=y to enable MCUboot

2. a DT overlay file, boards/stm32h7b3i_dk.overlay, to specify a custom partition layout:

   • boot_partition: MCUboot goes here
   • storage_partition: unused, could be used for a filesystem or NVS
   • slot0_partition: primary slot for the application
   • slot1_partition: secondary slot for the application
   • scratch_partition: used by MCUboot for swap operations

3. add the sysbuild/mcuboot directory with the following files:

   1. prj.conf: generic options for the MCUboot child image

   2. sysbuild/mcuboot/boards/stm32h7b3i_dk.overlay: MCUboot-specific overlay, used to select the correct partition for MCUboot. This overlay includes the above overlay, so the partition layout is defined in one place.

      zephyr,code-partition = &boot_partition;