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STM32H7B3NIH output PB8 is not working as GPIO, cannot be set high.

Jacob L
Associate II

I have tried everything I can think of to set PB8 high.

This is a custom PCB where PB8 is connected through a 1k resistor to a stepper driver input.

With board off, measuring pin to VCC resistance is 105kOhm, measured to GND is 95kOhm, so not directly shorted to GND

Checked routing - OK

Checked soldermask / pastemask - OK

Checked two different boards - same problem

Checked other GPIOs on port B - OK working fine

Checked errata - OK no mention of it

Checked datasheet - No mention of alternating functions which could cause this

Created new CubeMX project only configuring debugger and PB8 - Still does not work

Tried with TIM16.1 PWM - Not working

Tried setting pull-ups - Pin stays low

Tried configuring as OD mode with pull-up - Pin stays low

Anyone of you seen this problem before?

void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
 
  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOE_CLK_ENABLE();
  __HAL_RCC_GPIOG_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();
  __HAL_RCC_GPIOD_CLK_ENABLE();
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOJ_CLK_ENABLE();
  __HAL_RCC_GPIOI_CLK_ENABLE();
  __HAL_RCC_GPIOK_CLK_ENABLE();
  __HAL_RCC_GPIOF_CLK_ENABLE();
  __HAL_RCC_GPIOH_CLK_ENABLE();
 
  /*Configure GPIO pin : PB8 */
  GPIO_InitStruct.Pin = GPIO_PIN_8;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
 }
 
int main(void)
{
  HAL_Init();
 
  SystemClock_Config();
 
  MX_GPIO_Init();
 
  while (1)
  {
	  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_8, GPIO_PIN_SET);
	  HAL_Delay(100);
	  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_8, GPIO_PIN_RESET); 
  }
}
 
/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
 
  /*AXI clock gating */
  RCC->CKGAENR = 0xFFFFFFFF;
 
  /** Supply configuration update enable
  */
  HAL_PWREx_ConfigSupply(PWR_LDO_SUPPLY);
 
  /** Configure the main internal regulator output voltage
  */
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE3);
 
  while(!__HAL_PWR_GET_FLAG(PWR_FLAG_VOSRDY)) {}
 
  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLM = 1;
  RCC_OscInitStruct.PLL.PLLN = 10;
  RCC_OscInitStruct.PLL.PLLP = 2;
  RCC_OscInitStruct.PLL.PLLQ = 2;
  RCC_OscInitStruct.PLL.PLLR = 2;
  RCC_OscInitStruct.PLL.PLLRGE = RCC_PLL1VCIRANGE_3;
  RCC_OscInitStruct.PLL.PLLVCOSEL = RCC_PLL1VCOWIDE;
  RCC_OscInitStruct.PLL.PLLFRACN = 5462;
  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_CLOCKTYPE_D3PCLK1|RCC_CLOCKTYPE_D1PCLK1;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.SYSCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_HCLK_DIV1;
  RCC_ClkInitStruct.APB3CLKDivider = RCC_APB3_DIV2;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_APB1_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_APB2_DIV2;
  RCC_ClkInitStruct.APB4CLKDivider = RCC_APB4_DIV2;
 
  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }
}

Any other tests I can do?

Kind regard, Jacob

4 REPLIES 4
Sarra.S
ST Employee

Hello @Jacob L​ ,

it is possible that the PB8 pin is configured as an alternate function other than GPIO, to check that, try reading the GPIOx_MODER register :

0693W00000Y8d9TQAR.png 

To give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

Add a second delay in the loop so the toggle time high and low are balanced.​

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Up vote any posts that you find helpful, it shows what's working..

That seems to be set correctly. Any other suggestions? Does ST have a test board with an STM32H7B3NIH chip you could try?

0693W00000Y8iP2QAJ.png

Yeah good idea. I am just single stepping though so I would see it go high if it worked...