GitHub repository: LibreSolar/charge-controller-firmware
Description: Firmware for Libre Solar MPPT/PWM charge controllers

v21.0: tag_name: v21.0
body: ## Release notes

Most important improvements and bug fixes for this release:

- Upgrade to Zephyr v2.5
- Improved board revision handling
- Introduction of new task watchdog
- Support for CAN-FD interface on STM32G4 based boards
- Initial support for HRTIM in half bridge driver
- Support for data storage in flash partition (instead of EEPROM)
- Firmware version exposed via ThingSet is now derived from git tag and includes git commit hash
- Improved control and overvoltage protection in PWM charging algorithm
- Several small improvements in MPPT and battery charging functions

**Breaking change:** The serial in the UEXT connector is now used by default for the ThingSet protocol in order to allow connection of ESP32 WiFi/Bluetooth modules without firmware change. The setting can be changed via Kconfig.

## Tested boards

Below boards have been tested with this release, but also other boards are supposed to work.

| Board type | HW revisions |
|--|--|
| MPPT 2420 HC | v0.2 |
| MPPT 1210 HUS | v0.7 |
| PWM 2420 LUS | v0.3 |

20.0 - Ported to Zephyr v2.4: tag_name: v20.0
body: ## Release notes

The major change in this release is that the firmware has been completely ported from [Mbed](https://os.mbed.com/) v5 to [Zephyr RTOS](https://www.zephyrproject.org/) v2.4.

These are the main advantages of Zephyr:

- Excellent build system and customization (based on Devicetree and Kconfig from Linux kernel) that allows a clean separation between board specification and the firmware itself.
- Support of STM32G4 microcontrollers which are used in some newer charge controller designs
- Great community and open governance, so it’s a truly community-driven open source project.
- Strong focus on code quality and safety (aiming towards ISO 26262 and IEC 61508 certification)

## Tested boards

| Board type | HW revisions |
|--|--|
| MPPT 2420 HC | v0.1 |
| MPPT 2420 LC | v0.10 |
| MPPT 2420 RC | v0.2 |
| MPPT 1210 HUS | v0.7 |
| PWM 2420 LUS | v0.3 |

19.0 - First release: tag_name: v19.0
body: ## Release notes

First release of Libre Solar charge controller firmware with most important charge controller features implemented and tested:
- MPPT and PWM solar charging algorithms
- 2/3/4-stage charging profile for lead-acid and li-ion batteries
- Battery deep-discharge protection
- User-configurable voltage settings
- Temperature-compensation based on external battery temperature sensor
- Serial communication with ThingSet protocol
- OLED display support
- Data monitoring via CAN interface (if supported by the board hardware)

## Supported and tested boards

| Board type | HW revisions |
|--|--|
| MPPT 2420 LC | v0.10 |
| MPPT 1210 HUS | v0.4, v0.7 |
| PWM 2420 LUS | v0.2, v0.3 |