Below you can find a free, fully-functional, firmware for ATtiny2313: it is the starting point for building an IK1ZYW keypad for FT-817(ND). Please download and read through the User's Manual, that contains important hints for both builders and users.
The free firmware does:
A PCB artwork is available (free) on request.
Right click on the following links to save these files to your computer:
A generic User's Manual explains all functions that have been implemented so far and are not included in the free firmware version. Contact me if you need a firmware with specific functions. The following table shows what the keypad can do, as long as the code fits into the program memory: