HAL_UART_Transmit sends wrong data - c

Question

When ch = 0x80, on PC I receive 0x00,
When ch = 0x40, on PC I receive 0x80,
When ch = 0x20, on PC I receive 0x60,
When ch = 0x10, on PC I receive 0x10,
When ch = 0x08, on PC I receive 0x08,
When ch = 0x04, on PC I receive 0x04,
When ch = 0x02, on PC I receive 0x02,
When ch = 0x01, on PC I receive 0x01,
Can't figure what is going on here... I am attaching USART Initialization, Transmit Function and Main. I should be software issue, already tested the hardware and it's ok. MCU = STM32L011
void InitUSART(void)
{
GPIO_InitTypeDef GPIO_InitStruct;
USARTx_CLK_ENABLE();
UartHandle.Instance = USARTx;
UartHandle.Init.BaudRate = 9600;
UartHandle.Init.WordLength = UART_WORDLENGTH_8B;
UartHandle.Init.StopBits = UART_STOPBITS_1;
UartHandle.Init.Parity = UART_PARITY_NONE;
UartHandle.Init.HwFlowCtl = UART_HWCONTROL_NONE;
UartHandle.Init.Mode = UART_MODE_TX_RX;
//UartHandle.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_ENABLE;
HAL_UART_Init(&UartHandle);
/* Transmit Configuration */
USARTx_TX_GPIO_CLK_ENABLE();
GPIO_InitStruct.Pin = USARTx_TX_PIN;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = USARTx_TX_AF;
HAL_GPIO_Init(USARTx_TX_GPIO_PORT, &GPIO_InitStruct);
/* Receive Configuration */
USARTx_RX_GPIO_CLK_ENABLE();
GPIO_InitStruct.Pin = USARTx_RX_PIN;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = USARTx_TX_AF;
HAL_GPIO_Init(USARTx_RX_GPIO_PORT, &GPIO_InitStruct);
HAL_NVIC_SetPriority(USARTx_IRQn, 0, 1);
HAL_NVIC_EnableIRQ(USARTx_IRQn);
}
HAL_StatusTypeDef HAL_UART_Transmit(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size, uint32_t Timeout)
{
uint16_t* tmp;
uint32_t tickstart = 0;
/* Check that a Tx process is not already ongoing */
if(huart->gState == HAL_UART_STATE_READY)
{
if((pData == NULL ) || (Size == 0U))
{
return HAL_ERROR;
}
/* In case of 9bits/No Parity transfer, pData buffer provided as input paramter
should be aligned on a u16 frontier, as data to be filled into TDR will be
handled through a u16 cast. */
if ((huart->Init.WordLength == UART_WORDLENGTH_9B) && (huart->Init.Parity == UART_PARITY_NONE))
{
if((((uint32_t)pData)&1) != 0)
{
return HAL_ERROR;
}
}
/* Process Locked */
__HAL_LOCK(huart);
huart->ErrorCode = HAL_UART_ERROR_NONE;
huart->gState = HAL_UART_STATE_BUSY_TX;
/* Init tickstart for timeout managment*/
tickstart = HAL_GetTick();
huart->TxXferSize = Size;
huart->TxXferCount = Size;
while(huart->TxXferCount > 0U)
{
huart->TxXferCount--;
if(UART_WaitOnFlagUntilTimeout(huart, UART_FLAG_TXE, RESET, tickstart, Timeout) != HAL_OK)
{
return HAL_TIMEOUT;
}
if ((huart->Init.WordLength == UART_WORDLENGTH_9B) && (huart->Init.Parity == UART_PARITY_NONE))
{
tmp = (uint16_t*) pData;
huart->Instance->TDR = (*tmp & (uint16_t)0x01FFU);
pData += 2U;
}
else
{
huart->Instance->TDR = (*pData++ & (uint8_t)0xFFU);
}
}
if(UART_WaitOnFlagUntilTimeout(huart, UART_FLAG_TC, RESET, tickstart, Timeout) != HAL_OK)
{
return HAL_TIMEOUT;
}
/* At end of Tx process, restore huart->gState to Ready */
huart->gState = HAL_UART_STATE_READY;
/* Process Unlocked */
__HAL_UNLOCK(huart);
return HAL_OK;
}
else
{
return HAL_BUSY;
}
}
int main(void)
{
/* STM32L0xx HAL library initialization:
- Configure the Flash prefetch, Flash preread and Buffer caches
- Systick timer is configured by default as source of time base, but user
can eventually implement his proper time base source (a general purpose
timer for example or other time source), keeping in mind that Time base
duration should be kept 1ms since PPP_TIMEOUT_VALUEs are defined and
handled in milliseconds basis.
- Low Level Initialization
*/
HAL_Init();
/* Configure the system clock to 32 MHz */
SystemClock_Config();
InitUSART();
//Transmit(txBuffer, 2);
extern UART_HandleTypeDef UartHandle;
uint16_t ch = 0x80;
TransmitEnable();
while(1){
HAL_UART_Transmit(&UartHandle, &ch, 1, 0xFF);
HAL_Delay(5);
}
}

Answer 1

Looks like it was a clock issue after all. I was using internal 16 MHz oscillator (HSI) multiplied up to 32 MHz with PLL. Single baud width on 9600 baudrate was 110us. Now I switched to 4 MHz (internal MSI) and I am getting 104us per baud. Communication is flawless now.
RCC_ClkInitTypeDef RCC_ClkInitStruct ={0};
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_MSI;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0)!= HAL_OK)
{
while(1);
}
__HAL_RCC_PWR_CLK_ENABLE();
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE3);
__HAL_RCC_PWR_CLK_DISABLE();

Answer 2

Acording your sent source file, you programmed the usart as "8 bits", but this STM HAL routine compute data_bits+parity_bit=8bits(your selection). For standard text transmission, for this STM HAL should be: 9 bits (8_data_bits+one_parity_bit).