beside these blogs about our new interpretation of our original Digi-Keyer:
How Does the Modern Digi-Keyer Work? (digikey.de)
Updating the Original Digi-Keyer | DigiKey
You may also be interested in learning how Microchip implemented it in their PIC® 18F example using a PIC18F56Q71-I/6LX with morse-code in their mplab-mcc development environment:
GitHub - microchip-pic-avr-examples/pic18f56q71-morse-code-mplab-mcc: Transmit and receive morse code with the PIC18F56Q71 microcontroller