LPC UART receive issue

Question

I have a problem with UART RX FIFO. If I power up my UART peripheral I receive a RXFE error in my LSR register, UART TX works well.

I use LPC4088 with 120MHz PCLK and 115200Baud

I tried to read the register to clear the pending error but without success. Hope some of you can help.

void UART3_Init(void){
    LPC_SYSCTL->PCONP |= (1 << 25);                 // Enable Power & CLock for UART3
    LPC_UART3->LCR = (3 << 0)                   // Word Length: 8 Bit
            |(0 << 2)                   // Stop Bit: 1 Bit
            |(0 << 3)                   // Parity Enable: disabled
            |(1 << 7);                  // Divisor Latch: enabled
    LPC_UART3->DLL = 65;                        // Divisor Latch: 65 for 115200 Baud
    LPC_UART3->DLM = 0;                     // Divisor Latch: 0 for 115200 Baud
    LPC_UART3->FCR = (1 << 0)                   // FIFO enable: enabled
            |(1 << 1)                   // RX FIFO reset: enabled
            |(1 << 2);                  // TX FIFO reset: enabled
    LPC_UART3->FDR = (0 << 0)                   // Baudrate prescaler Value: DIVADDL = 0
            |(1 << 4);                  // Baudrate prescaler Value: MULVAL = 1
    LPC_UART3->LCR &= ~(1 << 7);                    // disable to lock Baud - without this no UART communication
}


char UART3_receive(void){
    while(!(LPC_UART3->LSR & (1 << 0)));                //wait until data arrives in Rx FIFO
    return LPC_UART3->RBR;
}

int main(void){
    CCLK runs with 120MHz

    //UART 3 Pins
    LPC_IOCON->p[0][25] = (3 << 0);         //UART3 TX  p[0][25]
    LPC_GPIO->DIR = (1 << 25);
    LPC_IOCON->p[0][26] = (3 << 0);         //UART3 RX  p[0][26]
    LPC_GPIO->DIR = (0 << 26);

    UART3_Init();

    char data = 0;

    while(1){
        data = UART3_receive();

        if(data == ENTER){
            //PRINT back to terminal "SUCCESS"
            ...
            ...
        }
    }
}

Answer 1

it looks like sending device has problems frame error or parity, check the senders buad rate, loop back test will make sure everything works fine.