The following steps can be used to control the TXFIFO empty interrupt:
1.Disable the TXFIFO empty interrupt. Write a 1 to can.IER[14].
2.Clear the TXFIFO empty interrupt. Write a 1 to can.ICR[14].
3.Enable the TXFIFO empty interrupt. Write a 1 to can.IER[14].
4.Read the TXFIFO empty status. Read can.ISR[14]. It indicates the status (whether TXFIFO is empty).