Write/Line Terminator for serial commands needs to be configurable (currently hard coded to carriage return)

[madeline-scyphers]

🚀 Feature Request

Because of the history of what GRANOLA grew out of, the write terminator was \r, but that needs to be a configurable option.

🔈 Motivation

Lots of other serial devices won't use a carriage return as the write/line terminator