Here are various posts I've modified the tag serial on. It's an incredibly broad tag that should be used with great care so as to avoid becoming totally meaningless (if not already). Vent disagreement here.
- Only tangentially related. icp/icsp would be better, but they don't exist.
- Serial programmer not working, what are the possible problem sources?
- Programming Atmega with serial port already has programmer which is reasonably specific.
- The question is about an lcd module. The fact it uses a serial interface is secondary.
- Arduino "Serial" = UART software/hardware module