UART framing error on STM32F0 device

[gaetanbusson]

Posted on March 19, 2015 at 12:18

Hello!

I am currently using STM32F030R8T8 for communication purpose (RS485). The functions I wrote to communicate seems to be working fine but most of the time the communication stops and refuses to restart.

I implemented the ''HAL_UART_ErrorCallback'' callback function to understand the bug. When the debugger stops in this callback, uart status is the following : ''HAL_UART_ERROR_FE''.

The only way I found to make the communication work again is to power off and on the microcontroller but this is not acceptable for the system I am currently developping.

My question is the following : How can I reinitialize UART softwarly from the ''HAL_UART_ErrorCallback'' callback function ?

I have already tried the following solutions but any of them are working :

-

         - 

Setting the error code to ''HAL_UART_ERROR_NONE''

-

- Setting the uart state to ''HAL_UART_STATE_READY''

-

- Calling ''HAL_UART_DeInit'' and then ''HAL_UART_Init'' functions

About framing error :

My microcontrroller is communicating with another STM32F030R8T8 that has exactly the same program (and so, the same clocking configuration). I use internal oscillator with no PLL and the frequency is low. Can I resolve my framing error by activation the PLL to give my microcontroller more accurency (my uart baudrate is 9600) ?

#uart-framing-error-on-stm32f0-de

[gregkam]

Posted on November 25, 2015 at 16:43

Hello, On My project I found a similar situation and after +3 days debugging to find the cause and its solution, essentially I solved with:

 

void HAL_UART_ErrorCallback(UART_HandleTypeDef *huart)

{

  //I implement this .. but eventually you can decide with different approach

  //Many macros/proc on this code .. is just to be a hint (mem/rec about this possibility)   __HAL_UART_CLEAR_OREFLAG(huart);   __HAL_UART_CLEAR_NEFLAG(huart);   __HAL_UART_CLEAR_FEFLAG(huart);

  /* Disable the UART Error Interrupt: (Frame error, noise error, overrun error) */

  __HAL_UART_DISABLE_IT(huart, UART_IT_ERR);  

 //The most important thing when UART framing error occur/any error is restart the RX process 

 if(huart->Instance == USART1)   {        //Restarting the RX, .. 1 byte. .. u8DATUartShortRxBuffer is My own rx buffer      HAL_UART_Receive_IT(huart, u8DATUartShortRxBuffer1, 1);   }

  if(huart->Instance == USART2)

  {        //Restarting the RX, .. 1 byte.      HAL_UART_Receive_IT(huart, u8DATUartShortRxBuffer2, 1);     }

}

void MX_USART1_UART_Init(void)

{

  huart1.Instance = USART1;

  huart1.Init.BaudRate = 115200;   huart1.Init.WordLength = UART_WORDLENGTH_8B;   huart1.Init.StopBits = UART_STOPBITS_1;   huart1.Init.Parity = UART_PARITY_NONE;   huart1.Init.Mode = UART_MODE_TX_RX;   huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;   huart1.Init.OverSampling = UART_OVERSAMPLING_16;   huart1.Init.OneBitSampling = UART_ONEBIT_SAMPLING_DISABLED ;   huart1.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;   HAL_UART_Init(&huart1);

}

/* USART2 init function */

void MX_USART2_UART_Init(void)

{

  huart2.Instance = USART2;

  huart2.Init.BaudRate = 4800;   huart2.Init.WordLength = UART_WORDLENGTH_8B;   huart2.Init.StopBits = UART_STOPBITS_1;   huart2.Init.Parity = UART_PARITY_NONE;   huart2.Init.Mode = UART_MODE_TX_RX;   huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;   huart2.Init.OverSampling = UART_OVERSAMPLING_16;   huart2.Init.OneBitSampling = UART_ONEBIT_SAMPLING_DISABLED ;   huart2.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;     //When parity is on use, from ST forum => 8-bit + parity is configured as 9-bit in STM32 implementation.   #if 0 //In some case, own ckts, is necessary a pin swap .. on My case it's disabled huart2.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_TXINVERT_INIT | UART_ADVFEATURE_SWAP_INIT; huart2.AdvancedInit.TxPinLevelInvert = UART_ADVFEATURE_TXINV_ENABLE;  huart2.AdvancedInit.Swap = UART_ADVFEATURE_SWAP_ENABLE; #endif     HAL_UART_Init(&huart2);

}

===================================================================================================

On My case, after a power-on the reception stops on UART2, but the transition still happens.

I observed:

1.) that on generated HAL codes was not including a basic code for the function void HAL_UART_ErrorCallback(UART_HandleTypeDef *huart), I put on My own module this above function; 2.) On debug mode by Keil, on TX/RX  no any problem was observed when the firmware was transferred directly (F8) without a new power-on; 3.) I think that when an error occur/HAL_UART_ErrorCallback, the reception must be restarted as on HAL_UART_ErrorCallback, independentlly of the STM32 families (STM32F0x, STM32F1x, STM32F2x, STM32F3x, STM32F4, ..) 4.) On real world Common errors that can happens and eventually stops the reception/communication w/ HAL_UART_ERROR_FE, HAL_UART_ERROR_NE, errors .. be aware and implement the re-start reception as similar above (HAL_UART_ErrorCallback). #define HAL_UART_ERROR_FE        ((uint32_t)0x00000004) #define HAL_UART_ERROR_NE        ((uint32_t)0x00000002)

Minor things that I observed:

With STM32CubeMX was configured all pin outs and generated the HAL device drivers.

After that all pin out was rightly configured I put attention to the clock sources (to be confident that clock jitter is not  problem source) (for UART1 clock Mux, I'm using SYSCLK=48MHz, PLLCLK from  with one crystal of 8MHz that the PLL Source Mux->HSE was adjusted to achieve the desired clock/48MHz) PLL Source Mux -> HSE, PREDiv=/1, VCOInput=8, PLLMul=x6 ..

I'm using Keil MDK-ARM 5.16a IDE, as compiler tools..

Tool Version Numbers: Toolchain:        MDK-ARM Professional  Version: 5.16a Toolchain Path:    C:\Keil_v5\ARM\ARMCC\Bin C Compiler:         Armcc.exe        V5.06 (build 20) Assembler:          Armasm.exe        V5.06 (build 20) Linker/Locator:     ArmLink.exe        V5.06 (build 20) Library Manager:    ArmAr.exe        V5.06 (build 20) Hex Converter:      FromElf.exe        V5.06 (build 20) CPU DLL:               SARMCM3.DLL          V5.16a Dialog DLL:         DCM.DLL              V1.13.2.0 Target DLL:             STLink\ST-LINKIII-KEIL_SWO.dll      V2.0.17.0 Dialog DLL:         TCM.DLL              V1.14.5.0

STM32CubeMX 4.11.0,  Firmware package for Family STM32F0 1.4.0

STM32F042C6Tx uController with LQFP48 package. UART1Tx = PIN30, UART2Rx=PIN31, UART2Tx=12 and UART2Rx=13

My microcontrroller is communicating with another embedded coomunication module (RF/module) by USART2.

Eventually this info can help you or someone else/other, Greg