What is this thing?

This is an experimental platform for an solar driven LoRa sensor station based on the

• Microcontroller: ST STM32U083CCT6
• Radio: Heltec HT-RA62 (Semtech SX1262)
• Charging Controller: TI BQ25185
• Flash: Windbond W25Q128JVS (128 MBit)
• Reset IC: APX803L05-32SA-7 (3.2V)
• LDO: HEERMICR HE9073A30MR (3.0V)

Plan is to´ use it as platform for a wireless sensor based on Zephyr.

Features

• Solar Input up to 18V (24V survival)
• 3A maximum load
• 1A maximum charge current
• Pseudo-MPPT (VINDPM)
• Power Path (= if the battery is fully charged and there's enough solar power the device is getting powered directly from solar. It also can mix battery and solar energy.)
• Two ADC signals for getting VLOAD and VBUS voltage using voltage dividers
• 3.7V LiPo either via 18650 block or JST-PH 2.0 connector

Lots if this stuff was already proven and validated in the project SolarMeshtasticNode.

Interfaces

• 4x I2C

• 1x UART

• 1x USB

• 1x GPIO with 4 available pins

Programming interfaces

The STM32U0 spits out its bootloader on the I2C, UART and USB.

For "comfort programming" it has a TC2030 where you can connect a Segger or ST-Link

Evaluation

Verification of PCB v0.0.1