Easy AVR USB Keyboard Firmware and Keymapper
EasyAVR is a keyboard firmware and keymapper GUI for custom keyboards based on USB AVRs. It is powerful but also really easy to use.
Read the documentation on GitHub:
View the source, report issues, and find releases on Github:
Ask questions in the GH thread:
Additional info at the DT Wiki:
Developed with generous support from JetBrains