Solved
[STM32 + LoRaWAN] LoRaWAN doesn't start when button is pressed (PA0)
Hi everyone,
I'm working with an STM32 microcontroller and the LoRaWAN stack provided by ST. My goal is to initialize LoRaWAN only when a button connected to pin PA0 is pressed.
I verified with a multimeter that PA0 is at 0V when idle and goes to 3.3V when the button is pressed, so the hardware seems fine.
In the code, I'm calling MX_LoRaWAN_Init() only if I detect PA0 is HIGH and a debounce time has passed. However, LoRaWAN never starts, even if I hold the button for several seconds.
Below is the full main.c file, including the logic for PA0 detection and conditional LoRaWAN startup:
/* 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"
#include "app_lorawan.h"
#include "LmHandler.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 */
#define PA0_HIGH_DETECTED 1
#define PA0_LOW_DETECTED 0
/* USER CODE END PD */
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */
/* USER CODE END PM */
/* Private variables ---------------------------------------------------------*/
/* USER CODE BEGIN PV */
uint8_t pa0_state = PA0_LOW_DETECTED;
uint8_t lorawan_started = 0;
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
/* USER CODE BEGIN PFP */
void Check_PA0_State(void);
void Start_LoRaWAN_When_Ready(void);
/* USER CODE END PFP */
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
/* 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();
/* USER CODE BEGIN 2 */
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
Check_PA0_State();
Start_LoRaWAN_When_Ready();
if(lorawan_started == 1)
{
MX_LoRaWAN_Process();
}
else
{
HAL_Delay(100);
}
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
/**
* @brief System Clock Configuration
* @retval None
*/
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
/* Enable HSE Oscillator and Activate PLL with HSE as source */
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
RCC_OscInitStruct.HSEState = RCC_HSE_OFF;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
RCC_OscInitStruct.PLL.PLLMUL = RCC_PLLMUL_6;
RCC_OscInitStruct.PLL.PLLDIV = RCC_PLLDIV_3;
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_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
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_1) != HAL_OK)
{
Error_Handler();
}
}
/**
* @brief GPIO Initialization Function
* @PAram None
* @retval None
*/
static void MX_GPIO_Init(void)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOA_CLK_ENABLE();
__HAL_RCC_GPIOH_CLK_ENABLE();
/* Configure GPIO pin Output Level */
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_10|GPIO_PIN_8, GPIO_PIN_RESET);
/* Configure GPIO pins : PA10 PA8 */
GPIO_InitStruct.Pin = GPIO_PIN_10|GPIO_PIN_8;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/*Configure PA0 as input pin */
GPIO_InitStruct.Pin = GPIO_PIN_0;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
}
/* USER CODE BEGIN 4 */
/**
* @brief Check the state of PA0 pin
* @retval None
*/
void Check_PA0_State(void)
{
pa0_state = (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_0) == GPIO_PIN_SET) ?
PA0_HIGH_DETECTED : PA0_LOW_DETECTED;
}
/**
* @brief Start LoRaWAN stack when PA0 is HIGH
* @retval None
*/
void Start_LoRaWAN_When_Ready(void)
{
static uint32_t last_debounce_time = 0;
const uint32_t debounce_delay = 50; // ms
if(lorawan_started == 1)
return;
if((pa0_state == PA0_HIGH_DETECTED) &&
((HAL_GetTick() - last_debounce_time) > debounce_delay))
{
MX_LoRaWAN_Init();
lorawan_started = 1;
}
else if(pa0_state == PA0_LOW_DETECTED)
{
last_debounce_time = HAL_GetTick();
}
}
/* USER CODE END 4 */
/**
* @brief This function is executed in case of error occurrence.
* @retval None
*/
void Error_Handler(void)
{
__disable_irq();
while (1)
{
}
}Do you have any idea why it doesn’t enter the initialization code?
Could something be wrong in my GPIO config or timing logic?
Any suggestions would be greatly appreciated. Thanks in advance!