Install Arduino IDE 2.3.6

link

Add stm32 Board and build

1. File -> Preferences -> Additional boards manager URLs -> https://github.com/stm32duino/BoardManagerFiles/raw/main/package_stmicroelectronics_index.json
2. Boards manager -> search stm32 by STM -> install
3. Select board Nucleo-64 , select part number Nucleo F030R8
4. Verify then Upload

Build cec-ctl for android

1. clone from link
2. put in android develop envrionment to compiler cec-ctl.
3. set CONFIG_CEC_GPIO=y in defconfig and add cec-gpio in dts.
4. make and re-download android image.
5. after android boot, there is a /dev/cec0 node.

connection

demo to turn off AVR(stm32)

waveform

demo to volume control AVR(stm32)

Reference

link