v21.0

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

Release notes

The major change in this release is that the firmware has been completely ported from Mbed v5 to Zephyr RTOS 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

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