Hi folks,
I'm working with the TM4C129ENCPDT in the current project on a custom PCB. Maybe I encountered an undocumted behavior of the UART receive FIFO.
Overview:
I configured the UART4 having the configuration:
9600Baud, (System clock is 16MHz)
8 databits, no parity, 1 stopbit
FIFO enabled, triggerlevel at 1/8 (2 bytes)
RX and TX interrupt enabled, loopback mode enabled
UART4->IBRD=0x68; UART4->FBRD=0x0B; UART4->LCRH=0x70; //Word-size (8Bit), FIFO active, 1 stoppbit UART4->IFLS=0x00; //FIFO triggerlevel (1/8) UART4->IM=0x30; //TX interrupt, RX interrupt UART4->CTL=0x381; //transmitter active, receiver aktiv, UART EN, LOOBBACK EN
Everyting related to the transmitter works fine. The interrupt handler is called after the FIFO contained less than 2 bytes.
Therefore the NVIC configuration works and the handler is correctly implemented.
Issue:
I'm not able to receive any data when the data bytes are not transfered as a packet. First I enabled the loopback mode when the initial data is transmitted by the device. There the receive FIFO and the associated interrupt works as ecpectet. Still having the loopback mode enabled I changed the data to be transmitted into three single characters, which are transmitted with a delay in between. In this case, no data is received and the receive interrupt is not triggerd. If I cross out the delays, all characters are received and the interrupt is fired.
Is there a configuration I missed during the initialisation? Futhermore, is there a possibility to avoid this behaviour?
Regards, Jannis
