STM32L4A6 GPIO PC8 pin can't be pulled to low

[Owenlu]

Hi,

i Pin PC8 is configured as GPIO,  but unfortuately, after execute following codes

HAL_GPIO_WritePin(GPIOC, GPIO_PIN_8, GPIO_PIN_SET) and

HAL_GPIO_WritePin(GPIOC, GPIO_PIN_8, GPIO_PIN_RESET) , the pin status didn't change,

always keeps in High status. other GPIOs like PD2 wroks with the same way.

Debug MCU configuration register (DBGMCU_CR) is in default setting (0x0).

CUBEIDE Version: 1.13.2

could you please let me know what is wrong?

[Andreas Bolsch]

Did you actually *verify* the GPIO register contents (in particular MODER, OTYPE, ODR, IDR) after the calls of HAL_GPIO_Write_pin against expected contents? LCD controller used?

[SofLit]

Hello  @Owenlu,

Please:

Check if you have already enabled GPIOC RCC clock.

Check if you've already configured the pin PC8 in output push-pull.

Check if there is something connected to PC8 pin that forces it to that level.

Check the content of ODR register after writing to the pin PC8.

[Owenlu]

@SofLit 

Check if you have already enabled GPIOC RCC clock.

A:Clock enabled:(RCC_AHB2ENR= 0x4200f)

Check if you've already configured the pin PC8 in output push-pull.

A:  GPIOC_MODER value 0xf2a1595d, MODER8 is 0x1, output

    GPIOC_OTYPER is 0, output push-pull, No PULL up/Down.

Check if there is something connected to PC8 pin that forces it to that level.

A: PC8 now is isolated from PCB, no other connection

Check the content of ODR register after writing to the pin PC8.

A: after setting GPIOC_ODR=0x100 

[Owenlu]

yes, registers value is as expected. 

there is no LCD interface/controller used in the project.