Help to use PA15 as GPIO Output on NUCLEO-L476RG

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@DZado.2 wrote:

I did two changes:

1) I removed the lines (as gbm proposed):

//LL_GPIO_SetAFPin_8_15(GPIOA,LL_GPIO_PIN_15,LL_GPIO_AF_5);

//LL_GPIO_SetPinMode(GPIOA,LL_GPIO_PIN_15,LL_GPIO_MODE_OUTPUT);

1) And I added 

LL_AHB2_GRP1_EnableClock(LL_AHB2_GRP1_PERIPH_GPIOA);

in addition to

__HAL_RCC_GPIOA_CLK_ENABLE();

 

Now it is working. I have no clue why.

If I remove LL_AHB2_GRP1_EnableClock(LL_AHB2_GRP1_PERIPH_GPIOA), it does not work.

Would you please explain why?

 

 

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I'm not sure? The LL and HAL are setting the same register/bit, though the LL is static inline

Look at the disassembly to see what each is doing.

// HAL
#define __HAL_RCC_GPIOA_CLK_ENABLE() do { \
 __IO uint32_t tmpreg; \
 SET_BIT(RCC->AHB2ENR, RCC_AHB2ENR_GPIOAEN); \
 /* Delay after an RCC peripheral clock enabling */ \
 tmpreg = READ_BIT(RCC->AHB2ENR, RCC_AHB2ENR_GPIOAEN); \
 UNUSED(tmpreg); \
 } while(0)





// LL
#define LL_AHB2_GRP1_PERIPH_GPIOA RCC_AHB2ENR_GPIOAEN

LL_AHB2_GRP1_EnableClock(LL_AHB2_GRP1_PERIPH_GPIOA);

__STATIC_INLINE void LL_AHB2_GRP1_EnableClock(uint32_t Periphs)
{
 __IO uint32_t tmpreg;
 SET_BIT(RCC->AHB2ENR, Periphs);
 /* Delay after an RCC peripheral clock enabling */
 tmpreg = READ_BIT(RCC->AHB2ENR, Periphs);
 (void)tmpreg;
}