USART Tx interrupt (STM32)

[uplifting_mind]

Hello,
I need complete program with interrupt from USART Rx and Tx. Rx interrupt is working fine, but with Tx I have problems. As I was awared, I must use a FIFO buffer for storing data from printf function and in interrupt handler I must send this data from FIFO to USART transmit register.
In my code, first step of this is working - data from printf are actualy going to FIFO buffer. But in second step, code in interrupt handler don´t send any data from FIFO to USART.

In order to tx interrupt I wrote this function, which is placing characters from printf to FIFO buffer. It is calling from fputc(int ch, FILE *f) function and works fine.

void FIFO_PUT(char ch)
{
      if(COUNT < FIFO_SIZE)
      {
       FIFO[COUNT] = ch;
       COUNT ++;
      }
}

The next function I wrote is this one. It should be sending a characters from FIFO buffer to USART. It is calling from interrupt handler.

void FIFO_GET(void)
{
    char j;
    char ch;
         
    for (j=0;j<10; j++)
    {
    ch = FIFO[j];
    USART_SendData(USART1, ch);
    ch = 0;
    }
}

I was been awared that USART_SendData() can only be used once per TXE interrupt. So I tried to replace this piece of code by this one (from example code for STM32F10...):

if (USART_GetITStatus(USART1, USART_IT_TXE) != RESET)
{
      USART_SendData(USART1, FIFO[COUNT]);
         
      if(COUNT == FIFO_SIZE)
    {
      /* Disable the USARTx Transmit interrupt */
      USART_ITConfig(USART1, USART_IT_TXE, DISABLE);
    }
}

It still don´t work. Can someone help me?

 

[jayanth.devarayanadurga]

Hope these will help

**broken link removed**

https://www.micromouseonline.com/2009/12/31/stm32-usart-basics/#axzz2h3Y5iYeP

https://www.keil.com/download/docs/359.asp

 

[milind.a.kulkarni]

I think Jayanth post no 1 gives you answer - there is interrupt driven UART is written by 'devil' at Posted: 3/13/2013 6:42 PM ...... I think that should work..... try that my through was you need to modify -

 USART_ITConfig(USART1, USART_IT_TXE, DISABLE); // original
// Modified to 
 USART_ITConfig(USART1, USART_IT_TXE, ENABLE); // as you need to made TXE enable interrupt