CODEWITHSUNDEEP
cembeddedstm32microcontrollerseven-segment-display
Theja
Theja

Reputation: 75

Nothing shows up on four digit seven segment display in run mode - stm32

Few days ago, I posted a question regarding the seven segment display with stm32(f401re). I have completed the coding part for the display to show particular four digit number that I provide as an input. I number I want to display is 1014.

Here is the code for the I created:

while (1)
  {
    /* USER CODE END WHILE */
      
    num_display_func(1014);

    /* USER CODE BEGIN 3 */
  }

Here is the fucntion that is called :

void num_display_func(uint16_t numtodisplay){

    int place_value = 1000;
    int num = numtodisplay;
    uint16_t active_pin = GPIO_PIN_9;
    int count;
    for(count = 0; count<4; count++){

        uint8_t digit_extract = num/place_value; //dividing the num by 1000 to extract the first digit,1234/1000->1
        num %=place_value;                       
        place_value /=10;                       

        HAL_GPIO_WritePin(GPIOA, active_pin, SET);
        displayDigit(digit_extract);
        HAL_GPIO_WritePin(GPIOA, active_pin, RESET);

        active_pin <<= 1; //shift the pin by 1 to activate the second display
        HAL_Delay(100);


    }
}

displayDigit() is as follows:

void displayDigit(uint8_t number){


    GPIOC->ODR |= GPIOx_SEGMENTS_MASK;  //Clear the segment bits (Setting the bits to HIGH for common Anode config)

    uint8_t digit = segmentCodes[number];

    GPIOC->ODR &= (digit & GPIOx_SEGMENTS_MASK );

}

Here is the demo that shows the problem:
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When I manually debug the code by setting breakpoint at the end of the function,

void displayDigit(uint8_t number)

every time the execution reaches the breakpoint, I see the change in display number.
But when I hit RUN, all the segments are blank and nothing appears on the display.

How to make the display show the number? Is there any delay that am I missing ?

Upvotes: 1

Views: 135

Answers (1)

Der Dipper
Der Dipper

Reputation: 11

I think you should put your HAL Delay directly below your displayDigit Function. I think the Time between enabling the display and disabling it before switching to the next is to short.

I would try this order Enable digit 0 -> Set Pins for displaying the number -> Wait for x ms -> Disable digit 0 -> Enable Digit 1 -> Set Pins for displying the number .....

I think you realy shortly enable the display but thats too short to see it.

Upvotes: 1

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