I am in a process of making a nanosatellite on which I am considering putting an APRS digipeater. I know about micro-modem based on ATmega 328P but it is pretty power hungry. MX614 has really good power stats; however, I am unable to find any clear documentation on how to implement it with a radio. Rather I am only getting the circuitry for line connection. Please help on connection.
The atmega or any microcontroller worth their salt has built in serial ports just a matter of reading the datasheet and programming the controller as such.
Your asking how to implement it as a radio. It is rather straight forward.
Carefully read the controller datasheet.
Take note that the controller has fuses to determine which pin in each port behaves, this should be in your code that sets it up.
After that rhen set up each pin to your desire again read the datasheet for the controller.
The thing about microcontrollers they are depdent on fuse and register settings.
Pay particular attention to the USART section or the 2 wire serial section those pins that they are on.
It looks like you want to built something remote, implament something that sits and listens to the input allow you to have control that way you can change the way the transeciver behaves.
Take a high frequency that is beyond the speech and have it filtered out from the voice stream and have it converted into a data stream their you have remote control over the device.