In the framework of a flight control system consisting of several electromechanical actuators, a real time system is implemented involving power electronics, electric motors, sensors, mechanics, a central PC104 computer and 4 microcontrollers. The communication between the central computer and the 4 microcontrollers is performed via CAN-Bus interface. On the PC104 computer, I have a CAN module with only 2 CAN channels, so I need 2 more modules for our application. However, I am afraid that the integration of an extra CAN module will impact the CPU performance. What do you think? Another solution could be to implement a module with 4 CAN built channels. Do you think it will make any difference?

 

Why can't you attach all microcontrollers on the same CAN-bus? Or share two on each bus?
You don't say anything about which speed your CAN networks are running or anything about the message density, but the total message density should probably be the same if you share them across 4 buses or 2. It's the total number and size of the messages that is going to be an issue for the host computer bus, not the number of interfaces.