Another method for processor communication is accomplished by it using the Event FIFO for transmitting and receiving. This is initiated by the processor and the TCAN4550-Q1 provides interrupts as described as follows.

For transmitting, enabling the Tx Event FIFO option in the M_CAN requires SPI writes to the Tx Event FIFO acknowledge register to manage the fill level. If these updates are not made, the Tx Event FIFO eventually gives a Tx Event FIFO full (interrupt) and then the Tx Event FIFO Element Lost (interrupt).

For receiving, if the Rx messages are stored in Rx FIFO, then SPI writes are required to the Rx FIFO Acknowledge register to manage the fill level. If this SPI access is not working, the Rx FIFO fills and gives a Rx FIFO 0/1 Full (interrupt) and then Rx FIFO 0/1 Message Lost (interrupt).

These are runtime checks that indirectly ensure the SPI interface is working properly.