Transceiver-Microcontroller???

Hi!!!
Could you help me on interfacing a transceiver with a microcontroller???
i want a real time clock on the circuit this it could be implemented with the crystal on microcontroller???
if yes how shall i choose the crystal???
Thanks anyway!!!

The simplest way to implement a RTC is to use a deticated RTC chip, many manufactures offer such chips, most of em use a I²C or similar bus
like this one for example
https://www.electro-tech-online.com/custompdfs/2004/05/DS1337.pdf

If you want a timer in real time you can use a crystal such as 18.432MHz to get 1/1000th sec. Just need one divisible by a binary number. If you want the actual time an RTC chip is the better solution.