Electrical – STM32F103. How to use PB4 as normal GPIO? NJTRST remap not working

hal-librarymicrocontrollerstm32stm32f10x

I need to use PB4 as a normal GPIO digital output pin. I have a custom designed board where this pin is connected to the CS of a SPI device, so just using another pin isn’t possible.

I’m using the HAL for developing the firmware. The code I use for configuring GPIO is:

__HAL_AFIO_REMAP_SWJ_NONJTRST();
__HAL_RCC_GPIOB_CLK_ENABLE();
GPIO_InitTypeDef config_gpio = {0};
config_gpio.Pin = GPIO_PIN_4;
config_gpio.Mode = GPIO_MODE_OUTPUT_PP;
config_gpio.Pull = GPIO_NOPULL;
config_gpio.Speed = GPIO_SPEED_FREQ_HIGH;
HAL_GPIO_Init(GPIOB, &config_gpio);
HAL_GPIO_WritePin(GPIOB, GPIO_PIN_4, GPIO_PIN_RESET);

After that, PB4 is always pulled high and I can't set it low, probably because it keeps behaving as NJTRST, so I can’t use it as a normal output.

It seems that the macro __HAL_AFIO_REMAP_SWJ_NONJTRST() doesn’t do anything.

Best Answer

It is needed to call

__HAL_RCC_AFIO_CLK_ENABLE();

before configuring remaps.

Related Solutions

Electronic – STM32F103 Systick Interrupt stopped working when debugging in ram – (Coocox IDE)

You need to relocate the vector table — right now, the processor is probably still using the copy of the vector table in FLASH, which will point into an old version of your code in FLASH. (Or, if you've erased FLASH since you started developing in SRAM, the vector table in use will be blank.)

If you're using the STM32 Standard Peripheral Library (SPL), you can define the VECT_TAB_SRAM macro to have it set the appropriate flags to use a vector table in SRAM. If you're going the bare-metal route, you need to set the TBLOFF field of VTOR to point to the base of SRAM (0x02000000 on STM32F1).

Electronic – STM32F103 GPIO not working

Here is a simple program that should help:

/* main.c
** Simple program for Olimex STM32-H103 (STM32F103RB) to flash LED on PC12
**
*/

#include <stm32f10x.h>

void delay(void);

void main(void)
{
  // I/O port C clock enable
  RCC->APB2ENR = RCC_APB2ENR_IOPCEN;
  // Set PC_12 to output 
  GPIOC->CRH &= ~(GPIO_CRH_MODE12 | GPIO_CRH_CNF12);
  GPIOC->CRH |= GPIO_CRH_MODE12;

  while(1)
  {
    GPIOC->BSRR = (1<<12);
    delay();
    GPIOC->BRR = (1<<12);
    delay();
  }
}

void delay(void)
{
  volatile unsigned int i;

  for (i = 0; i < 20000; i++)
    ;
}

It was written for the Rowley CrossWorks compiler.

Best Answer

Related Solutions

Electronic – STM32F103 Systick Interrupt stopped working when debugging in ram – (Coocox IDE)

Electronic – STM32F103 GPIO not working

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