Why can I only use 2 GPIO pins?

[Starman]

I am only able to use 2 GPIO pins with an STM32F767ZI on a Nucleo-144 board. The issue doesn't appear to be with any specific pins, it's just that only 2 pins seem to output any voltage at all.

Take this code for example:

main.c

#include "./headers/stm32f767xx.h"
#include <stdint.h>
 
int main(void)
{
    initMotor(0);
    initMotor(1);
    initMotor(2);
    uint32_t a = 0;
    while (1)
    {
        if (a >= 25000)
        {
            stepMotor(0);
            stepMotor(1);
            stepMotor(2);
            a = 0;
        }
        a++;
    }
}

./drivers/motor.c

#include "../headers/stm32f767xx.h"
 
void initMotor(int step_pin)
{
    RCC->AHB1ENR |= RCC_AHB1ENR_GPIOGEN;
    GPIOG->MODER |= (0b01 << (step_pin * 2));
    GPIOG->OTYPER &= ~(0b1 << step_pin);
    GPIOG->ODR &= ~(0b1 << step_pin);
}
 
void stepMotor(int step_pin)
{
    GPIOG->ODR ^= (0b1 << step_pin);
}

Using this code, only 2 of the 3 GPIO ports give out a voltage as I would expect them to. If main.c is modified to remove any of the three motors/pins, the other two will work (they give out a voltage which changes from HIGH to LOW every time period).

This issue extends even when adding LEDs which are already on the board.

Only a maximum of 2 GPIO pins (regardless of whether it is GPIOA, GPIOB, etc.) ever seem to work.

I am very unsure of the cause of this, and would appreciate any direction that people can point me in.

[Starman]

the peripheral clock had already been enabled though, would OR'ing the register (as if enabling it again, but essentially a useless operation) really make a difference?

[waclawek.jan]

Also, it hardly explains that some of the bits are set, others are not.

In 'F7, AFAIK, GPIO is on AHB which runs at the same clock as the Cotex(sic!) core.

JW

[Imen.D]

Hello All,

Thanks @Community member​ , for reporting this typo (Cotex). I raised it internally for fix in the coming release of RM0410.

I will have a look on this reported issue regarding GPIOG register and I will take the necessary action.

Thanks

Imen

[waclawek.jan]

Thanks, Imen.

Jan

@Imen DAHMEN​