Question
STM32F4xx HAL UART BAUD Timing Issues
Posted on January 24, 2015 at 19:54
Hi there... Using the non-hal on an STM32F2xx, I can read/write at 3,333,333 BAUD without a problem. When I port the code to STM32F4xx, I am unable to read/write to the USART1 at the same BAUD rate - instead, it times out.
If I change the baud rate to 4,300,000 - it works. If I change it back to 3,333,333 - it doesn't work. Does anyone have an idea of why this could be happening? Here is my non-working code...UART_HandleTypeDef huart1;
int main(void) {
HAL_Init();
__GPIOA_CLK_ENABLE();
__GPIOB_CLK_ENABLE();
__GPIOC_CLK_ENABLE();
GPIO_InitTypeDef GPIO_InitStruct;
// --------------------------------------------------------------------------- LED
GPIO_InitStruct.Pin = GPIO_PIN_15;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
// --------------------------------------------------------------------------- USART 1
/**USART1 GPIO Configuration
PA9 ------> USART1_TX
PA10 ------> USART1_RX
PA11 ------> USART1_CTS
PA12 ------> USART1_RTS
*/
__USART1_CLK_ENABLE();
GPIO_InitStruct.Pin = GPIO_PIN_9 | GPIO_PIN_10;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_PULLUP;
GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF7_USART1;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
GPIO_InitStruct.Pin = GPIO_PIN_11 | GPIO_PIN_12;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF7_USART1;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
huart1.Instance = USART1;
huart1.Init.BaudRate = 3333333;
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_RTS_CTS;
huart1.Init.OverSampling = UART_OVERSAMPLING_8;
HAL_UART_Init(&huart1);
// ---------------------------------------------------------------------------
for (;;) {
HAL_GPIO_WritePin(GPIOC, GPIO_PIN_15, GPIO_PIN_SET);
HAL_Delay(250);
HAL_GPIO_WritePin(GPIOC, GPIO_PIN_15, GPIO_PIN_RESET);
HAL_Delay(250);
HAL_UART_Transmit(&huart1, (uint8_t *)&''Hello'', 5, 1000);
}
} 