ESP32 - Over The Air (OTA) Update task
Goal
The ESP-IDF API provides a update mechanism that allows a device to update itself based on data received while the normal firmware is running.
This component makes this API available as a component. It checks for an OTA update on a network server, and if present (and different) it applies the update. Upon completion, the device resets to activate the downloaded code.
We use the term "update" loosly, because it can also be used to downgrade the firmware.
Example
An example can be found in the test directory.
The WIFI_SSID and WIFI_PASSWORD can be provisioned using the Kconfig. If empty, the device will use credentials from flash memory instead.
Initially the build/ota_update_test.bin should be flashed using the UART. From then on, it will automatically update from file server spedified by OTA_UPDATE_FIRMWARE_URL in Kconfig.
Usage
The software relies on the master ESP-IDF SDK version v4.3-dev-472-gcf056a7d0 and accompanying tools.
Clone this component in your project's components directory, or use it as a git submodule.
Copy the Kconfig.example to Kconfig and update the configuration.
In your project's sdkconfig.defaults, specify a custom partition.csv that includes a coredump partition. An example of sdkconfig.defaults is shown below.
CONFIG_PARTITION_TABLE_CUSTOM=y
CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions.csv"
CONFIG_PARTITION_TABLE_FILENAME="partitions.csv"
CONFIG_ESPTOOLPY_FLASHSIZE_4MB=y
An example of partition.csv is shown below.
# Name, Type, SubType, Offset, Size, Flags
nvs, data, nvs, 0x09000, 0x004000,
otadata, data, ota, 0x0d000, 0x002000,
phy_init, data, phy, 0x0f000, 0x001000,
factory, app, factory, 0x010000, 0x150000,
ota_0, app, ota_0, 0x160000, 0x140000,
ota_1, app, ota_1, 0x2A0000, 0x140000,
coredump, data, coredump, 0x3E0000, 128k
Before start the component's task, call nvs_flash_init(), and establish WiFi connectivity. Then create the ota_update_task using
xTaskCreate(&ota_update_task, "ota_update_task", 4096, NULL, 5, NULL);
The OTA server should support either HTTP or HTTPS. If you WiFi name and password are provisioned using Kconfig it will be part of the binary, so you should be more comfortable using local server.
To determine if the currently running code is different as the code on the server, it compares the project name, version, date and time. Note that these are not always updated by the SDK. The best way to make sure they are updated is by committing your code to Git and building the project from scratch.
Feedback
I love to hear from you. Please use the Github discussions board to contact me.