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hitsumen
hitsumen
Associate III
November 14, 2016
Question

How to configure GPIO input?

  • November 14, 2016
  • 2 replies
  • 1375 views
Posted on November 14, 2016 at 21:35

Good day,

What I want is:

If I put GND to GPIOD_4 I want to LED ON.

If high impedance then LED OFF.

I attached my schematic with CHRG pin connected to GPIOD_4.

Is it possible to pull up internally gpio?

I wrote some code:

void SysTick_Handler(void)

{

if(GPIO_ReadInputDataBit(GPIOD, GPIO_Pin_4)){

STM_EVAL_LEDOn(LED3);

}

        else

{

STM_EVAL_LEDOff(LED3);

}

TimingDelay_Decrement();

}

void input_init(void){

  GPIO_InitTypeDef GPIO_InitStructure;

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);

 

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;

  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;

  GPIO_Init(GPIOD, &GPIO_InitStructure);

}

int main(void)

{

DBGU_Init();

 

printf(''\nSysTick_Configuration!'');

SysTick_Configuration();

 

STM_EVAL_LEDInit(LED3);

  

input_init();

  while(1);

}

    This topic has been closed for replies.

    2 replies

    Walid FTITI_O
    Walid FTITI_O
    Visitor II
    November 15, 2016
    Posted on November 15, 2016 at 10:44

    Hi

    kovaliov.nikolaj,

    If an input is configured with an internal pull-up, it will be high unless it is externally driven low.

    The converse is true with pull-down inputs.

    -Hannibal-

    hitsumen
    hitsumenAuthor
    Associate III
    November 17, 2016
    Posted on November 17, 2016 at 09:40

    Ah, i tested it on discovery board on which PD4 pin is connected to CS43L22 RESET pin which is R43 10k pulled low. So thats why it did not worked for me.

    Modified code abit which worked.

    void SysTick_Handler(void){

    if(GPIO_ReadInputDataBit(GPIOD, GPIO_Pin_6)){

    STM_EVAL_LEDOff(LED3);

    }

    else{

    STM_EVAL_LEDOn(LED3);

    }

    TimingDelay_Decrement();

    }

    void input_init(void){

    GPIO_InitTypeDef GPIO_InitStructure;

    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;

    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;

    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;

    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;

    GPIO_Init(GPIOD, &GPIO_InitStructure);

    }

    int main(void)

    {

    DBGU_Init();

    printf(''\nSysTick_Configuration!'');

    SysTick_Configuration();

    STM_EVAL_LEDInit(LED3);

      

    input_init();

    while(1);

    }

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