UART communication using STM8L discovery

[Suthar.Narendra]

Posted on August 23, 2015 at 08:54

Hi,

I am new to use STM8L controller.

I am just trying to put Simple character on UART using STM8L discovery board.

But I am failed to do this.

Following is my code for this.

void main(void)

{

    

    u8 Data = 'N';

    

    CLK_DeInit();

    GPIO_DeInit(GPIOC); 

    

    CLK_HSICmd(ENABLE);

    CLK_SYSCLKSourceConfig(CLK_RTCCLKSource_HSI);

    CLK_SYSCLKDivConfig(CLK_SYSCLKDiv_1);

        

    GPIO_ExternalPullUpConfig(GPIOA, GPIO_Pin_3, ENABLE);

    GPIO_ExternalPullUpConfig(GPIOA, GPIO_Pin_2, ENABLE);

    

    USART_DeInit(USART1);

    CLK_PeripheralClockConfig(CLK_Peripheral_USART1, ENABLE);

    USART_Init(USART1, 9600, USART_WordLength_8b, USART_StopBits_1, USART_Parity_No, USART_Mode_Tx | USART_Mode_Rx);

    USART_ClockInit(USART1, USART_Clock_Disable, USART_CPOL_Low, USART_CPHA_1Edge, USART_LastBit_Disable);

    USART_Cmd(USART1, ENABLE);        

    

    while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET)             // Wait for transmition to complete

    {

    }

    

    USART_SendData8(USART1, Data);

             

    GPIO_Init(GPIOC, GPIO_Pin_7, GPIO_Mode_Out_PP_High_Fast);                   // Init Blue LED

//    GPIO_Init(GPIOE, GPIO_Pin_7, GPIO_Mode_Out_PP_High_Fast);                   // Init Green LED

    

    /* Infinite loop */

    while (1)

    {

  // Wait for transmition to complete

        {

        }

    

        USART_SendData8(USART1, Data);

        GPIO_SetBits(GPIOC, GPIO_Pin_7);

        delay_ms(1000);

        

        GPIO_ResetBits(GPIOC, GPIO_Pin_7);

        delay_ms(1000);

        

    }

}

I am using IAR workbetch for STM8 evolution version.

[Philipp Krause]

Posted on August 26, 2015 at 10:31

There is a tutorial for using the UART on the STM8L-Discovery at

http://colecovision.eu/stm8/STM8L-DISCOVERY%20Serial.shtml

it uses SDCC, but that shouldn't be a problem, since IAR and SDCC are the two most standard-compliant compielrs for the STM8, so porting between them is easy.

Philipp

P.S.: It seems in your code, you are trying to use the library provided by STM. I also tried to use that one a two years ago, but there was a bug in UART handling in there. Don't knwo if its fixed by now. The tutorial linked above does not use the library provided by STM.

[Suthar.Narendra]

Posted on September 03, 2015 at 15:53

It is working..

Thanks..

[munish4u911ex]

Posted on October 04, 2016 at 15:00

Hello Krause,

I am using STM8L051 with STVD Cosmic compiler + Std peripheral lib and have been successful at transmitting characters but I am having problem in receiving, both in Interrupt & polling modes. Can you plz state what is the library bug you were referring to? I am using version

V1.6.1 / 30-September-2014

of the library. I can see a change in the release notes for V1.6.0 / 28-June-2013 as:

stm8l15x_usart.c/.h Update ''USART_ClearITPendingBit()'' function and parameter list. I dont know if the bug is corrected by that. Anyway my polling code is as follows:

void main(void) 

 { GPIO_Init(GPIOA, GPIO_Pin_All ,GPIO_Mode_Out_PP_Low_Slow);
GPIO_Init(GPIOB, GPIO_Pin_All, GPIO_Mode_Out_PP_Low_Slow);

//GPIO_Init(GPIOC, GPIO_Pin_All, GPIO_Mode_Out_PP_Low_Fast); //UART Pins: PC5, PC6
GPIO_Init(GPIOD, GPIO_Pin_0, GPIO_Mode_Out_PP_Low_Slow);
//EXTI_SetPinSensitivity(EXTI_Pin_1, EXTI_Trigger_Falling); //Push Button
CLK_PeripheralClockConfig(CLK_Peripheral_USART1, ENABLE);
GPIO_ExternalPullUpConfig(GPIOC, GPIO_Pin_5|GPIO_Pin_6, ENABLE); 
//Pullups on PC5, PC6
USART_Init(USART1, 115200, USART_WordLength_8b, USART_StopBits_1, USART_Parity_No, (USART_Mode_Rx|USART_Mode_Tx));
USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
USART_Cmd(USART1, ENABLE);
enableInterrupts();
printf(
''UART Tx OK!

''
); 
//working
/**/
while
(1)
{ 
while
(USART_GetFlagStatus(USART1,USART_FLAG_RXNE) == RESET); 
//wait till Rxd ... HANGS HERE

temp8 = USART_ReceiveData8(USART1);
USART_ClearFlag(USART1, USART_FLAG_RXNE);
USART_SendData8(USART1, temp8);
while
(USART_GetFlagStatus(USART1,USART_FLAG_TXE)==RESET); 
//wait till Txd
delay_ms(100);
}
while
(1) 
//working
{ printf(
''Count: %d 

''
, temp++);
delay_ms(1000);
}
}
//main() ends
char
putchar(
char
c) 
//implementation for printf
{
USART_SendData8(USART1, c);
while
(USART_GetFlagStatus(USART1,USART_FLAG_TXE)==RESET); 
//wait till Txd
}

When using Interrupts, the interrupt never comes. I am able to view waveforms on Rx pin of STM8, so I know data is going to it. What am I doing wrong?