Dear TI support,
we have run into a problem when developing the FlexRay driver for the TMS570LS MCU and we hope you can help resolve it. We would like to know if there is any hardware implemented way of determining if a valid data frame or a null frame was sent out in the static segment to the FlexRay bus upon receiving a TX interrupt.
The problem is that we have no way of knowing in the next TX interrupt after releasing a message buffer for transmission that the data was really sent out to the bus or only a null frame was sent out, and the data frame will only be transmitted in the next cycle. Of course this can be overcome by a software implemented solution, but we would like to avoid the additional processing overhead.
When using the Transfer Unit with the Transfer on Event to System Memory feature enabled, we can easily determine in the TU transfer status interrupt if a received frame was a null frame by checking the NFI flag of the message buffer header which was transferred into the system memory. We are looking for a similar solution for determining in the TX transmit interrupt if the transmitted frame was a null frame or not.
Best Regards
