LAB: GPIO Digital InOut 7-segment(eval board)

LAB: GPIO Digital InOut 7-segment

Date: 2025-09-02

Author/Partner:

Github: repository link

Demo Video: Youtube link

PDF version:

Introduction

In this lab, you are required to create a simple program to control a 7-segment display to show a decimal number (0~9) that increases by pressing a push-button.

You must submit

  • LAB Report (*.pdf)

  • Zip source files(lab***.c, ecRCC2.h, ecGPIO2.h etc...).

    • Only the source files. Do not submit project files

Requirement

Hardware

  • MCU

    • NUCLEO-F411RE

  • Actuator/Sensor/Others:

    • eval board

Software

  • PlatformIO, CMSIS, EC_HAL library

Exercise

Fill in the table

Port/Pin

Description

Register setting

Port B Pin 5

Clear Pin5 mode

GPIOB->MODER &=~(3<<(5*2))

Port B Pin 5

Set Pin5 mode = Output

GPIOB->MODER |=____________

Port B Pin 6

Clear Pin6 mode

GPIOB->MODER &=~___________

Port B Pin 6

Set Pin6 mode = Output

GPIOB->MODER |=____________

Port B Pin Y

Clear PinY mode

GPIOB->MODER &=~___________

Port B Pin Y

Set PinY mode = Output

GPIOB->MODER |=____________

Port B Pin 5~9

Clear Pin5~9 mode

GPIOB->MODER &=~___________

Set Pin5~9 mode = Output

GPIOB->MODER |=____________

Port X Pin Y

Clear Pin Y mode

GPIOX->MODER &=~___________

Set Pin Y mode = Output

GPIOX->MODER |=____________

Port B Pin5

Set Pin5 otype=push-pull

GPIOB->OTYPER =____________

Port B PinY

Set PinY otype=push-pull

GPIOB-> OTYPER =____________

Port B Pin5

Set Pin5 ospeed=Fast

GPIOB->OSPEEDR =____________

Port B PinY

Set PinY ospeed=Fast

GPIOB-> OSPEEDR =____________

Port B Pin 5

Set Pin5 PUPD=no pullup/down

GPIOB->OTYPER =____________

Port B Pin Y

Set PinY PUPD=no pullup/down

GPIOB-> OTYPER =____________

Problem 0: Preparation

Procedure

Complete the Tutorial: 7-segment Display.

LogoTutorial: 7-Segment Display | ECykkim.gitbook.io

You must check the 7-segment display can show all the number from 0 to 9.

  • Give 'HIGH' signal to each 7-segment pin of 'a'~'g'

  • Observe if that LED is turned ON or OFF

  • Check another 7-segment display leds

    • Example: Connect VCC to all 'a'~'g' pins

Complete the required functions that displays numbers on 7-segment FND.

These functions must be moved to ecGPIO2.h,ecGPIO2.c

Update your library header

  • ecGPIO2.h, ecGPIO2.c

// Initialize 7 DOUT pins for 7 segment leds
void seven_seg_FND_init(void); 

// Select display: 0 to 3
// Display a number 0 - 9 only
void seven_seg_FND_display(uint8_t  num, uint8_t select);

Problem 1: Display a Number with Button Press

Procedure

Create a new project under the directory \repos\EC\lab\LAB_GPIO_7segment

  • The project name is “LAB_GPIO_7segment”.

  • Create a new source file named as “LAB_GPIO_7segment.c”

  • Update platformio.ini for VS.Code : Read here for detail

Create a code that increases the displayed number from 0 to 9 with each button press.

  • After the number '9', it should start from '0' again.

Configuration

Configure the MCU GPIO

Digital In for Button (B1)
Digital Out for 7-Segment

Digital In

Digital Out

PA4

PB7,PB6,PB5,PB4,PB3,PB2,PB1,PB0 ('a'~'h', respectively) PC3,PC4,PA11,PA10 ('FND_0'~FND_3, respectively)

PULL-UP

Push-Pull, No Pull-up-Pull-down, Medium Speed

Code

Sample Code.

#include "stm32f4xx.h"
#include "ecGPIO2.h"
#include "ecRCC2.h"

#define BUTTON_PIN PA_4

void setup(void){
    // Intialize System Clock
    RCC_HSI_init();
    GPIO_init(BUTTON_PIN, INPUT);  // calls RCC_GPIOC_enable()
    // and Others
    // [YOUR CODE GOES HERE]    
    seven_seg_FND_init(); 
};

int main(void) {
    setup();
    uint8 numDisplay=8;
    uint8 selectFND=0;

    while (1) {
        // [YOUR CODE GOES HERE]    
        seven_seg_FND_display(numDisplay,selectFND);
        // [YOUR CODE GOES HERE]    
        // [YOUR CODE GOES HERE]    
    }
}

Your code goes here: ADD Code LINK such as github

Explain your source code with necessary comments.

// YOUR MAIN CODE ONLY
// YOUR CODE

Your code goes here: ADD Code LINK such as github

Explain your source code with the necessary comments.

// YOUR MAIN CODE ONLY
// YOUR CODE

Connection Diagram

Circuit diagram (if needed)

You need to include the circuit diagram

image

Results

Experiment images and results

Show experiment images /results

Add demo video link

Discussion

  1. Analyze the result and explain any other necessary discussion.

  1. Draw the truth table for the BCD 7-segment decoder with the 4-bit input.

Answer discussion questions

** YOUR Truth-table  goes here**

  1. What are the common cathode and common anode of 7-segment display?

Answer discussion questions

  1. Does the LED of a 7-segment display (common anode) pin turn ON when 'HIGH' is given to the LED pin from the MCU?

Answer discussion questions

Reference

Complete list of all references used (github, blog, paper, etc)

Troubleshooting

(Option) You can write Troubleshooting section

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