Use better names for the variables here: https://github.com/StartleStudio/nixie/blob/master/firmware/1.0/nixie_atmega_firmware_1.0/nixie_atmega_firmware_1.0.ino#L4-L10. It is very hard to track what expression1 or expression8 means inside the code. Name them as something like **status_cmd** etc
Use better names for the variables here: https://github.com/StartleStudio/nixie/blob/master/firmware/1.0/nixie_atmega_firmware_1.0/nixie_atmega_firmware_1.0.ino#L4-L10. It is very hard to track what expression1 or expression8 means inside the code. Name them as something like status_cmd etc