[TWAI-3.13.4] Reading the Interrupt Register May Lead to a Transmit Interrupt Being Lost

Affected revisions: v0.0 v1.0 v1.1 v3.0 v3.1

Description

The TWAI controller’s interrupt signals are cleared by reading the INTERRUPT_REG. However, if a transmit interrupt occurs whilst the INTERRUPT_REG is being read (i.e., in the same APB clock cycle), the transmit interrupt is lost.

Workarounds

When a message is awaiting completion of transmission (i.e., transmission has been requested), users should also check the STATUS_TRANSMIT_BUFFER bit each time the INTERRUPT_REG is read. A set STATUS_TRANSMIT_BUFFER bit whilst the TWAI_TRANSMIT_INT_ST is not indicates a lost transmit interrupt.

Solution

No fix scheduled.