38.6.6.8 Tx Event Handling

To support Tx event handling the CAN has implemented a Tx Event FIFO. After the CAN has transmitted a message on the CAN bus, Message ID and timestamp are stored in a Tx Event FIFO element. To link a Tx event to a Tx Event FIFO element, the Message Marker from the transmitted Tx Buffer is copied into the Tx Event FIFO element.

The Tx Event FIFO can be configured to a maximum of 32 elements. The Tx Event FIFO element is described in 38.7.4 Tx Event FIFO Element.

When a Tx Event FIFO full condition is signaled by IR.TEFF, no further elements are written to the Tx Event FIFO until at least one element has been read out and the Tx Event FIFO Get Index has been incremented. In case a Tx event occurs while the Tx Event FIFO is full, this event is discarded and interrupt flag IR.TEFL is set.

To avoid a Tx Event FIFO overflow, the Tx Event FIFO watermark can be used. When the Tx Event FIFO fill level reaches the Tx Event FIFO watermark configured by TXEFC.EFWM, interrupt flag IR.TEFW is set.

When reading from the Tx Event FIFO, two times the Tx Event FIFO Get Index TXEFS.EFGI has to be added to the Tx Event FIFO start address TXEFC.EFSA.