536871948 = 0x2000040C the address of rxChar array in memory.
Your handler is now expecting 10 characters, you make no attempt to process them in that form
I'd recommend mastering C coding before trying DMA. Perhaps work with colleagues or supervisors to guide you.
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file : main.c
* @brief : Main program body
******************************************************************************
* @attention
*
* Copyright (c) 2025 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
*/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
/* USER CODE END Includes */
/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
/* USER CODE END PTD */
/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
/* USER CODE END PD */
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */
/* USER CODE END PM */
/* Private variables ---------------------------------------------------------*/
UART_HandleTypeDef huart1;
UART_HandleTypeDef huart2;
DMA_HandleTypeDef hdma_usart1_rx;
/* USER CODE BEGIN PV */
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_DMA_Init(void);
static void MX_USART1_UART_Init(void);
static void MX_USART2_UART_Init(void);
/* USER CODE BEGIN PFP */
/* USER CODE END PFP */
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
#define NMEA_BUFFER_SIZE 512
uint8_t nmeaBuffer[NMEA_BUFFER_SIZE];
uint8_t rxChar[10], rcvd_msg;
volatile uint16_t nmeaIndex = 0;
volatile uint8_t nmeaComplete = 0;
volatile char nmeaSentence[NMEA_BUFFER_SIZE];
/* GNSS configuration commands */
GPIO_PinState Test_Jumper;
const char* GNSS_SET_RATE_1HZ = "$PMSTK220,1000*1F\r\n"; // Set update rate to 1Hz
uint8_t GNSS_SET_BAUD_9600[] = "$PSTMSETPAR,115200*17\r\n"; // Set baud rate to 9600
const char* GNSS_SET_NMEA_OUTPUT = "$PMSTK314,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n"; // Enable GGA and RMC sentences
void GNSS_Init()
{
/* Send configuration commands to GNSS module */
// UART_Start_Receive_DMA(&huart1, nmeaBuffer, NMEA_BUFFER_SIZE);
// HAL_UART_Transmit(&huart1, (uint8_t*)GNSS_SET_BAUD_9600, 25, HAL_MAX_DELAY);
// HAL_Delay(100);
// HAL_UART_Transmit(&huart1, (uint8_t*)GNSS_SET_RATE_1HZ, strlen(GNSS_SET_RATE_1HZ), HAL_MAX_DELAY);
// HAL_Delay(100);
// HAL_UART_Transmit(&huart1, (uint8_t*)GNSS_SET_NMEA_OUTPUT, strlen(GNSS_SET_NMEA_OUTPUT), HAL_MAX_DELAY);
// HAL_Delay(100);
/* Start receiving data in interrupt mode */
HAL_UART_Receive_IT(&huart1, &rxChar[0], sizeof(rxChar));
}
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
if (huart->Instance == USART1)
{
int i;
for(i=0; i<sizeof(rxChar); i++) // For each character requested
{
if (rxChar[i] == '$') // Start of NMEA sentence
{
nmeaIndex = 0;
}
if (nmeaIndex < NMEA_BUFFER_SIZE - 1)
{
nmeaBuffer[nmeaIndex++] = rxChar[i];
if (rxChar[i] == '\n') // End of NMEA sentence
{
nmeaBuffer[nmeaIndex] = '\0';
if (nmeaComplete != 1)
{
strcpy(nmeaSentence, (char *)nmeaBuffer); // copy to an inactive buffer
nmeaComplete = 1;
}
}
}
else
{
nmeaIndex = 0; // Buffer overflow protection
}
/* Restart interrupt reception */
HAL_UART_Receive_IT(&huart1, &rxChar[0], sizeof(rxChar));
}
}
void USART2OutString(char *str)
{
HAL_UART_Transmit(&huart2, (uint8_t *)str, strlen(str), HAL_MAX_DELAY);
}
void ProcessNMEASentence(char* sentence)
{
/* Forward NMEA sentence to debug UART */
USART2OutString(sentence);
/* Add your NMEA parsing code here */
// strstr() seems like a poor choice the sentence starts at the first character
/* Example: Check for specific NMEA sentences
if (strstr(sentence, "$GPRMC") != NULL)
{
// Parse RMC sentence
}
else if(strstr((char*)sentence, "$GPGGA") != NULL)
{
// Parse GGA sentence
}
*/
}
/* USER CODE END 0 */
/**
* @brief The application entry point.
* @retval int
*/
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_DMA_Init();
MX_USART1_UART_Init();
MX_USART2_UART_Init();
/* USER CODE BEGIN 2 */
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
GNSS_Init();
uint8_t data[] = "Hello world\n\r";
char msg[100];
USART2OutString(data);
while (1)
{
Test_Jumper = HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_6);
if (Test_Jumper)
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_RESET);
else
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_SET);
if (nmeaComplete)
{
ProcessNMEASentence(nmeaSentence);
nmeaComplete = 0;
}
}
}
/**
* @brief System Clock Configuration
* @retval None
*/
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
/** Initializes the RCC Oscillators according to the specified parameters
* in the RCC_OscInitTypeDef structure.
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSIDiv = RCC_HSI_DIV4;
RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/** Initializes the CPU, AHB and APB buses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI;
RCC_ClkInitStruct.SYSCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.AHBCLKDivider = RCC_HCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_APB1_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
{
Error_Handler();
}
}
/**
* @brief USART1 Initialization Function
* @PAram None
* @retval None
*/
static void MX_USART1_UART_Init(void)
{
/* USER CODE BEGIN USART1_Init 0 */
/* USER CODE END USART1_Init 0 */
/* USER CODE BEGIN USART1_Init 1 */
/* USER CODE END USART1_Init 1 */
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_ONE_BIT_SAMPLE_DISABLE;
huart1.Init.ClockPrescaler = UART_PRESCALER_DIV1;
huart1.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
if (HAL_UART_Init(&huart1) != HAL_OK)
{
Error_Handler();
}
if (HAL_UARTEx_SetTxFifoThreshold(&huart1, UART_TXFIFO_THRESHOLD_1_8) != HAL_OK)
{
Error_Handler();
}
if (HAL_UARTEx_SetRxFifoThreshold(&huart1, UART_RXFIFO_THRESHOLD_1_8) != HAL_OK)
{
Error_Handler();
}
if (HAL_UARTEx_DisableFifoMode(&huart1) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN USART1_Init 2 */
/* USER CODE END USART1_Init 2 */
}
/**
* @brief USART2 Initialization Function
* @PAram None
* @retval None
*/
static void MX_USART2_UART_Init(void)
{
/* USER CODE BEGIN USART2_Init 0 */
/* USER CODE END USART2_Init 0 */
/* USER CODE BEGIN USART2_Init 1 */
/* USER CODE END USART2_Init 1 */
huart2.Instance = USART2;
huart2.Init.BaudRate = 115200;
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_ONE_BIT_SAMPLE_DISABLE;
huart2.Init.ClockPrescaler = UART_PRESCALER_DIV1;
huart2.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
if (HAL_UART_Init(&huart2) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN USART2_Init 2 */
/* USER CODE END USART2_Init 2 */
}
/**
* Enable DMA controller clock
*/
static void MX_DMA_Init(void)
{
/* DMA controller clock enable */
__HAL_RCC_DMA1_CLK_ENABLE();
/* DMA interrupt init */
/* DMA1_Channel1_IRQn interrupt configuration */
HAL_NVIC_SetPriority(DMA1_Channel1_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(DMA1_Channel1_IRQn);
}
/**
* @brief GPIO Initialization Function
* @PAram None
* @retval None
*/
static void MX_GPIO_Init(void)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
/* USER CODE BEGIN MX_GPIO_Init_1 */
/* USER CODE END MX_GPIO_Init_1 */
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOA_CLK_ENABLE();
__HAL_RCC_GPIOB_CLK_ENABLE();
/*Configure GPIO pin Output Level */
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_RESET);
/*Configure GPIO pin : PA5 */
GPIO_InitStruct.Pin = GPIO_PIN_5;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/*Configure GPIO pin : PA6 */
GPIO_InitStruct.Pin = GPIO_PIN_6;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/* USER CODE BEGIN MX_GPIO_Init_2 */
/* USER CODE END MX_GPIO_Init_2 */
}
/* USER CODE BEGIN 4 */
/* USER CODE END 4 */
/**
* @brief This function is executed in case of error occurrence.
* @retval None
*/
void Error_Handler(void)
{
/* USER CODE BEGIN Error_Handler_Debug */
/* User can add his own implementation to report the HAL error return state */
__disable_irq();
while (1)
{
}
/* USER CODE END Error_Handler_Debug */
}
#ifdef USE_FULL_ASSERT
/**
* @brief Reports the name of the source file and the source line number
* where the assert_param error has occurred.
* @PAram file: pointer to the source file name
* @PAram line: assert_param error line source number
* @retval None
*/
void assert_failed(uint8_t *file, uint32_t line)
{
/* USER CODE BEGIN 6 */
/* User can add his own implementation to report the file name and line number,
ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
/* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
