Hello Georges,
The normal operating range for MCU - the battery voltage is in range from 5.5V to 18V. The maximum short peaks of transient voltage is allowed up to 40V. Please note all those peaks could have negative impact to the device reliability and have to be eliminated by design.
The CAN module specifications are in Table H-2, and Table H-3 of the RM. It is for the standard 5V supply voltage level. The absolute maximum ratings described in Table H-1 are considered as very short peak levels during transients only. The influence to reliability is valid also. The CAN module is intended for use in the 12V systems only In case you wonder about higher voltage level systems the workaround for power supply and CAN interface must done. One example is described in AN5082.
I wish you many success in your design.
Best Regards,
Stano.
