I want to connect a number of ATmega328P microcontrollers over a CAN bus. I found out that I will need some MCP2515 and MCP2551 ICs. In different schemas I sometimes see a 8 MHz crystal on the MCP2515 and sometimes a 16 MHz crystal.
This is the desired setup:
Multiple ATmega328P chips for a home automation project. The amount of data to be sent is really limited: switch on relay, switch off relay... so the speed on the CAN bus can be low.
What frequency should I take? Or doesn't it matter? Do I need to specify anything else needed to make the decision?
Is the use of a crystal on the ATmega required? Or can I use the internal clock of 8 MHz or 16 MHz?