STM32duino / wiringPi gpio  thermal printer filter for cups 

Clockworkpi CPI-58 (grayscale)

serial:/dev/ttyACM0?baud=115200+bits=8+parity=none+flow=none

serial:/tmp/DEVTERM\_PRINTER\_IN?baud=115200+bits=8+parity=none+flow=none

## build
sudo apt -y install libcups2-dev
make
sudo make install