LAB: GPIO Digital InOut 7-segment

Date: 2023-09-22

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(main*.c, ecRCC.h, ecGPIO.h etc...).

  • Only the source files. Do not submit project files

Requirement

Hardware

• MCU

  • NUCLEO-F411RE

• Actuator/Sensor/Others:

  • 7-segment display(5101ASR)

  • Array resistor (330 ohm)

  • decoder chip(74LS47)

  • breadboard

Software

• Keil uVision, CMSIS, EC_HAL library

Exercise

Fill in the table

Port/Pin	Description	Register setting
Port A Pin 5	Clear Pin5 mode	GPIOA->MODER &=~(3<<(5*2))
Port A Pin 5	Set Pin5 mode = Output	GPIOA->MODER |=____________
Port A Pin 6	Clear Pin6 mode	GPIOA->MODER &=~___________
Port A Pin 6	Set Pin6 mode = Output	GPIOA->MODER |=____________
Port A Pin Y	Clear PinY mode	GPIOA->MODER &=~___________
Port A Pin Y	Set PinY mode = Output	GPIOA->MODER |=____________
Port A Pin 5~9	Clear Pin5~9 mode	GPIOA->MODER &=~___________
	Set Pin5~9 mode = Output	GPIOA->MODER |=____________
Port X Pin Y	Clear Pin Y mode	GPIOX->MODER &=~___________
	Set Pin Y mode = Output	GPIOX->MODER |=____________
Port A Pin5	Set Pin5 otype=push-pull	GPIOA->OTYPER =____________
Port A PinY	Set PinY otype=push-pull	GPIOA-> OTYPER =____________
Port A Pin5	Set Pin5 ospeed=Fast	GPIOA->OSPEEDR =____________
Port A PinY	Set PinY ospeed=Fast	GPIOA-> OSPEEDR =____________
Port A Pin 5	Set Pin5 PUPD=no pullup/down	GPIOA->OTYPER =____________
Port A Pin Y	Set PinY PUPD=no pullup/down	GPIOA-> OTYPER =____________

Problem 1: Connecting 7-Segment Display

Procedure

Review 7-segment Decoder and Display from Digital Logic lecture.

• Read here: 7-segment tutorial

• Read here: How to connect 7-segment decoder to MCU

The popular BCD 7-segment decoder chips are 74LS47 and CD4511.

Instead of using the decoder chip, we are going to make the 7-segment decoder with the MCU programming.

Do not use the 7-segmment decoder

Connect the common anode 7-segment with the given array resistors.

Apply VCC and GND to the 7-segment display.

Apply 'H' to any 7-segment pin 'a'~'g' and observe if that LED is turned on or off

• example: Set 'H' on PA5 of MCU and connect to 'a' of the 7-segment.

Connection Diagram

Circuit diagram

You need to include the circuit diagram

image

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

---

Problem 2: Display 0~9 with button press

Procedure

1. 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”

• Refer to the sample code

You MUST write your name on the source file inside the comment section.

2. Include your updated library in \repos\EC\lib\ to your project.

• ecGPIO.h, ecGPIO.c

• ecRCC.h, ecRCC.c

1. Declare and Define the following functions in your library

   • You can refer to an example code of 7-segment control

   ecGPIO.h

void sevensegment_init(void); 
void sevensegment_decoder(uint8_t  num);

1. First, check if every number, 0 to 9, can be displayed properly

2. Then, create a code to display the number from 0 to 9 with each button press. After the number '9', it should start from '0' again.

Configuration

Digital In for Button (B1)	Digital Out for 7-Segment
Digital In	Digital Out
PC13	PA5, PA6, PA7, PB6, PC7, PA9, PA8, PB10 ('a'~'h', respectively)
PULL-UP	Push-Pull, No Pull-up-Pull-down, Medium Speed

Fill in the table

Code

Sample Code.

#include "stm32f4xx.h"
#include "ecGPIO.h"
#include "ecRCC.h"

#define LED_PIN 	5
#define BUTTON_PIN 13

void setup(void);
	
int main(void) { 
	// Initialiization --------------------------------------------------------
	setup();
	unsigned int cnt = 0;
	
	// Inifinite Loop ----------------------------------------------------------
	while(1){
		sevensegment_decode(cnt % 10);
		if(GPIO_read(GPIOC, BUTTON_PIN) == 0) cnt++; 
		if (cnt > 9) cnt = 0;
		for(int i = 0; i < 500000;i++){}
	}
}


// Initialiization 
void setup(void)
{
	RCC_HSI_init();	
	GPIO_init(GPIOC, BUTTON_PIN, INPUT);  // calls RCC_GPIOC_enable()
	sevensegment_init();
}

Your code goes here: ADD Code LINK such as github

Explain your source code with necessary comments.

// YOUR MAIN CODE ONLY
// YOUR CODE

Results

Experiment images and results

Show experiment images /results

Add demo video link

Problem 3: Using both 7-Segment Decoder and 7-segment display

Procedure

Now, use the decoder chip (74LS47). Connect it to the bread board.

Then, you need only 4 Digital out pins of MCU to display from 0 to 9.

Connection Diagram

Circuit diagram

You need to include the circuit diagram

image

1. Work on the same project and code.

• i.e. : project “LAB_GPIO_7segment”. and source file named as “LAB_GPIO_7segment.c”

void sevensegment_display_init(void); 
void sevensegment_display(uint8_t  num);

1. First, check if every number, 0 to 9, can be displayed properly

2. Then, create a code to display the number from 0 to 9 with each button press. After the number '9', it should start from '0' again.

Configuration

Digital In for Button (B1)	Digital Out for 7-Segment
Digital In	Digital Out
PC13	PA7, PB6, PC7, PA9
PULL-UP	Push-Pull, No Pull-up-Pull-down, Medium Speed

Reference

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

Troubleshooting

(Option) You can write Troubleshooting section