I'm using FIQ for serial comms. It works but when transmitting I'm getting extra FIQ UART interrupts at about 330KHz (consuming a lot of processing time) even though the transmitter buffer emty status is not asserted. Has anyone come across this?
I should add this is an ADuC 7026 and I suspect the UART interrupt bit is staying asserted all the time when a transmit is in progress, not just when the TX buffer is empty.
Fixed it myself now. Was monitoring TEMT instead of THRE in the interrupt routine.