W1209 thermostat firmware using stm8-tiny.

• Copy tools/tools/Linux/udev/70-st-link.rules to /etc/udev/ and run udevadm control --reload-rules.

make -f <target>.mk

make -f <target>.mk clean

make -f <target>.mk erase

make -f <target>.mk upload

From board edge in:

• GND
• RST
• SWIM
• 3.3V/5V

• https://github.com/TG9541/stm8ef/wiki/Board-W1209
• https://vivonomicon.com/2018/07/15/the-w1209-a-sometimes-stm8-based-digital-thermostat/