UART0 RX FIFO Usage in other Interrupt Routine

Hello Amit

I only wrote this for give general view. Ok I share my own code. 

void Comm()
{
    if(UART0_RIS_R&UART_RIS_RXRIS)        // hardware RX FIFO >= 2 Bytes
    {
      UART0_ICR_R = UART_ICR_RXIC;        // acknowledge RX FIFO
      send_flag = 1;
      rx_timeout = 0;
    }

    rx_timeout++;

    if(rx_timeout>1000)
    {
        UART0_ICR_R = 0x00;        // acknowledge RX FIFO
        rx_timeout = 0;
    }

    if(send_flag ==1)
    {
        UART_OutChar(ADC_Data);
        send_flag =0;
    }
}

void main()

{

while(1)
{


if(DR_Flag ==1)
{

ADC_Data_Reading(); // When Interrupt comes firstly ADC data will read
Comm(); // After ADC reading, I would like to check RX FIFO and if it is N1 byte data , I would like to send N2 byte  data
DR_Flag = 0;
}

}

Hello

I was confused about this implementation. Now I have only one problem. Let me explain it.

I am using RS-485 communication. I get data from terminal program with UART ınterrupt. I see correct data in my receive data register. But when I send it only sends one byte data. I am sharing related code. 

void UART0_Handler(void)
{
  if(UART0_RIS_R&UART_RIS_RXRIS)
  {       // hardware RX FIFO >= 2 items
    UART0_ICR_R = UART_ICR_RXIC;        // acknowledge RX FIFO
    // copy from hardware RX FIFO to software RX FIFO
    while((UART0_FR_R&UART_FR_RXFE) == 0)
    {
        ReceiveData[0] = (char)(UART0_DR_R&0xFF);
        ReceiveData[1] = (char)(UART0_DR_R&0xFF);
        send_flag =1;
    }
  }
}

void main()
{
while(1)
{
if(ReceiveData[0] == 20 && ReceiveData[1] == 30 && send_flag ==1 )
	        {
                    RS_485_COM = 0x01;  // RS485 Transmitter Mode
	            UART_OutChar(0x01);
	            UART_OutChar(0x02);
                    while((UART0_FR_R&UART_FR_TXFE) == 0); // Transmit FIFO empty
	            RS_485_COM = 0x00;  // RS485 Receiver Mode
	            send_flag =0;
	        }
}
}

After runnng, I only see 0x01 value on terminal. But when I send continous data, I see 0x01and 0x02 respectively on terminal screen. 

Before I make RS-485 to receive mode, How can I be sure N byte data sent and I am ready to switch RS-485 in to receiver mode. This problem is related with it. As I said when I contionus send, there is no problem

Regards

Hello Amit

I mean when I siwtch RS-485 to only transmitter mode, It sends 0x01 and 0x02 respectively.

I now realized that It does not send last byte. When I send 5 byte like 

 if(ReceiveData[0] == 20 && ReceiveData[1] == 30 && send_flag ==1 )
	        {
	       setbit(ADC_CS5,6);
               UART_OutChar(0x01);
               UART_OutChar(0x02);
               UART_OutChar(0x03);
               UART_OutChar(0x04);
               UART_OutChar(0x05);
               UART_OutChar(0x06);
               while((UART0_FR_R&UART_FR_TXFE) == 0);
               clrbit(ADC_CS5,6);
	       send_flag =0;
	        }

It sends 4-Byte and 5. Byte does not seem on terminal screen like when I send 2 byte, 2. byte didnt seem on terminbal screen.

I share my UART Initilization code 

void UART_Init(void)
{
  SYSCTL_RCGCUART_R |= 0x01;            // activate UART0
  SYSCTL_RCGCGPIO_R |= 0x01;            // activate port A
  UART0_CTL_R &= ~UART_CTL_UARTEN;      // disable UART
  UART0_IBRD_R = 520;                    
  UART0_FBRD_R = 54;                    
                                        // 8 bit word length (no parity bits, one stop bit, FIFOs)
  UART0_LCRH_R = (UART_LCRH_WLEN_8|UART_LCRH_FEN);
  UART0_IFLS_R &= ~0x3F;                // clear TX and RX interrupt FIFO level fields
                                        // configure interrupt for RX FIFO >= 1/8 full
  UART0_IFLS_R += UART_IFLS_RX1_8;
                                        // enabl RX FIFO interrupts and RX time-out interrupt
  UART0_IM_R |= (UART_IM_RXIM|UART_IM_RTIM);
  UART0_CTL_R |= UART_CTL_UARTEN;       // enable UART
  GPIO_PORTA_AFSEL_R |= 0x03;           // enable alt funct on PA1-0
  GPIO_PORTA_DEN_R |= 0x03;             // enable digital I/O on PA1-0
                                        // configure PA1-0 as UART
  GPIO_PORTA_PCTL_R = (GPIO_PORTA_PCTL_R&0xFFFFFF00)+0x00000011;
  GPIO_PORTA_AMSEL_R = 0;               // disable analog functionality on PA
                                        // UART0=priority 2
  NVIC_PRI1_R = (NVIC_PRI1_R&0xFFFF00FF)|0x00004000; // bits 13-15
  NVIC_EN0_R = NVIC_EN0_INT5;           // enable interrupt 5 in NVIC
}

You are right. There are many devices in RS-485 line I only disable transmit for secure. Yes I added check condition.

Serkan

Hello Serkan,

Serkan said:

There are many devices in RS-485 line I only disable transmit for secure

For what secure? And after adding the check it did not work surprises me. Code please.

Regards

Amit