38.6.1 Principle of Operation

The CAN performs communication according to ISO 11898-1:2015 (identical to Bosch CAN protocol specification 2.0 part A,B, ISO CAN FD).

For FIFO and filter storage, the CAN module uses system RAM, which it accesses through a host AHB bus. Each CAN FD instance may use up to 4864 bytes of system memory.

All functions concerning the handling of messages are implemented by the Rx Handler and the Tx Handler. The Rx Handler manages message acceptance filtering, the transfer of received messages from the CAN Core to the Message RAM as well as providing receive message status information. The Tx Handler is responsible for the transfer of transmit messages from the Message RAM to the CAN Core as well as providing transmit status information.

Acceptance filtering is implemented by a combination of up to 128 filter elements where each one can be configured as a range, as a bit mask, or as a dedicated ID filter.