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STUser34
Associate III
February 4, 2025
Solved

Internal Pull up STM32G4 series

  • February 4, 2025
  • 12 replies
  • 1864 views

Hello,

I am using the internal pull up for the input pins, but when read the port status using the program, it always reads 0 instead of 1. I expected it to read 1 and if make that pin grounded it shall read 0. 

 

 

This topic has been closed for replies.
Best answer by Hl_st

I couldn´t see anything wrong in your code. I tried to do some easy example and it works right and pin input value is also seen in debugger. Do you have connected anything externally to MCU pins? 

 

 

int main(void)
{
 /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
 HAL_Init();

 /* Configure the system clock */
 SystemClock_Config();

 /* Initialize all configured peripherals */
 MX_GPIO_Init();
 /* USER CODE BEGIN 2 */
 /* USER CODE END 2 */

 /* Infinite loop */
 while (1)
 {
 HAL_GPIO_WritePin(USER_LED_GPIO_Port, USER_LED_Pin, 
 HAL_GPIO_ReadPin(INPUT_PULL_UP_GPIO_Port, INPUT_PULL_UP_Pin));
 }
}

static void MX_GPIO_Init(void)
{
 GPIO_InitTypeDef GPIO_InitStruct = {0};

 /* GPIO Ports Clock Enable */
 __HAL_RCC_GPIOC_CLK_ENABLE();
 __HAL_RCC_GPIOF_CLK_ENABLE();
 __HAL_RCC_GPIOA_CLK_ENABLE();

 /*Configure GPIO pin Output Level */
 HAL_GPIO_WritePin(USER_LED_GPIO_Port, USER_LED_Pin, GPIO_PIN_RESET);

 /*Configure GPIO pin : INPUT_PULL_UP_Pin */
 GPIO_InitStruct.Pin = INPUT_PULL_UP_Pin;
 GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
 GPIO_InitStruct.Pull = GPIO_PULLUP;
 HAL_GPIO_Init(INPUT_PULL_UP_GPIO_Port, &GPIO_InitStruct);

 /*Configure GPIO pin : USER_LED_Pin */
 GPIO_InitStruct.Pin = USER_LED_Pin;
 GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
 GPIO_InitStruct.Pull = GPIO_NOPULL;
 GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
 HAL_GPIO_Init(USER_LED_GPIO_Port, &GPIO_InitStruct);
}

 

 

 

12 replies

Hl_st
ST Employee
February 4, 2025

Hello,

can you also share complete configuration of these pins?

Thank you

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STUser34Author
Associate III
February 4, 2025

This is the code

#define ON 1

static void MX_GPIO_Init(void)
{
	GPIO_InitTypeDef GPIO_InitStruct = {0};

 /* GPIO Ports Clock Enable */
 __HAL_RCC_GPIOC_CLK_ENABLE();
 __HAL_RCC_GPIOF_CLK_ENABLE();
 __HAL_RCC_GPIOG_CLK_ENABLE();
 __HAL_RCC_GPIOA_CLK_ENABLE();
 __HAL_RCC_GPIOB_CLK_ENABLE();
 
 /* USER CODE BEGIN */

 /*Configure GPIO pin Output Level */
 // HAL_GPIO_WritePin(GPIOB, GPIO_PIN_11, GPIO_PIN_RESET);

 /*Configure GPIO pin : PB11 */
 GPIO_InitStruct.Pin = GPIO_PIN_11;
 GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
 GPIO_InitStruct.Pull = GPIO_PULLUP;
 HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

 GPIO_InitStruct.Pin = GPIO_PIN_12|GPIO_PIN_15;
 GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
 GPIO_InitStruct.Pull = GPIO_PULLUP;
 HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

 /*Configure GPIO pins : PC6 PC7 PC8 */
 GPIO_InitStruct.Pin = GPIO_PIN_6|GPIO_PIN_7|GPIO_PIN_8;
 GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
 GPIO_InitStruct.Pull = GPIO_PULLUP;
 HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

 /*Configure GPIO pins : PA8 PA9 PA10 */
 GPIO_InitStruct.Pin = GPIO_PIN_8|GPIO_PIN_9|GPIO_PIN_10;
 GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
 GPIO_InitStruct.Pull = GPIO_PULLUP;
 HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
 /* USER CODE END */
}
MC_VehicleMode_Status_t SetVehicleMode(MCI_Handle_t *pHandle)
{
 uint8_t l_portb_pin11_state_u8=0;
 uint8_t l_portb_pin12_state_u8=0;
 uint8_t l_porta_pin8_state_u8=0;
 uint8_t l_portc_pin7_state_u8 = 0;
 uint8_t l_portb_pin15_state_u8 = 0;
 uint8_t l_porta_pin9_state_u8 = 0;

 l_portb_pin11_state_u8 = HAL_GPIO_ReadPin(GPIOB,GPIO_PIN_11);
 l_portb_pin12_state_u8 = HAL_GPIO_ReadPin(GPIOB,GPIO_PIN_12);
 
 if(l_portb_pin11_state_u8 == ON)
 {
 pHandle->VehicleMode = MCM_REVERSE_MODE;
 }
 else if(l_portb_pin12_state_u8 == ON)
 {
 pHandle->VehicleMode = MCM_CITY_MODE;
 }
}

But in the code when i debug it always reads as 0 instead of 1. I have added only the main section of the code. Please let me know if anything else to be shared or added.

 

    Ozone
    Ozone
    Principal
    February 4, 2025

    I suppose the values are consistent with the input register values of the GPIO in the debugger.

    Have you tried a, say, 5k external pull-up resistor ?
    And have you physically measured the voltage on the respective pins ?

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