UART interrupt doesn't give interrupt for 1 byte while using FIFO

Hi I am using tm4c123gh6pz UART. I am getting Interrupt but while I enable FIFO and try to get interrupt using following command,

 UARTFIFOLevelSet(UART0_BASE, UART_FIFO_TX1_8, UART_FIFO_RX1_8);

for the Receive, I get interrupt after 2 byte. I think Receive FIFO is 12 bit x 16 FIFO. To get interrupt after each byte I have to disable the FIFO.

Is there any other way to keep the FIFO and get interrrupt after each Byte.

Please let me know

Thanks