8.6.5.4.4 Debug on CAN Support

Debug messages are stored into Rx Buffers. For debug handling three consecutive Rx buffers (for example, #61, #62, #63) have to be used for storage of debug messages A, B, and C. The format is the same as for an Rx Buffer or an Rx FIFO element (see Rx Buffer and FIFO Element).

Advantage: Fixed start address for the DMA transfers (relative to MCAN_RXBC.RBSA), no additional configuration required.

For filtering of debug messages Standard / Extended Filter Elements with SFEC / EFEC = ‘111’ have to be set up. Messages matching these filter elements are stored into the Rx Buffers addressed by SFID2 / EFID2[5:0].

After message C has been stored, the DMA request output m_can_dma_req is activated and the three messages can be read from the Message RAM under DMA control. The RAM words holding the debug messages will not be changed by the MCAN while m_can_dma_req is activated. The behavior is similar to that of an Rx Buffer with its New Data flag set.

After the DMA has completed, the MCAN is prepared to receive the next set of debug messages.