View source for TM4C123G LaunchPad - 7 Segment LED Source Code

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/*
 * Display minutes and seconds on the 4-digit 7-segment LED.
 *
*/

#include <stdint.h>
#include <stdlib.h>
#include "inc/tm4c123gh6pm.h"

#define NO_OF_DIGITS    4

/* 0 - 9 pattern for the common cathode configuration */
unsigned char digitPattern[] = {0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D, 0x7D, 0x07, 0x7F, 0x6F};
unsigned char digit_no[] = {0x10, 0x20, 0x40, 0x80};

/* for the common anode configuration */
// unsigned char digitPattern[] = {0xCF, 0xF9, 0xA4, 0xB0, 0x99, 0x92, 0x82, 0xF8, 0x80, 0x90};
// unsigned char digit_no[] = {0x1F, 0x2F, 0x4F, 0x8F};

void One_Second_Delay(void);
void delayMs(int n);

int seconds, minutes, minutesec;

int main(void)
{
    volatile unsigned long delay;
    int digits;


    seconds = 0;
    minutes = 0;
    minutesec = 0;

    SYSCTL_RCGC2_R |= 0x01;     /* enable clock to GPIOA */
    SYSCTL_RCGC2_R |= 0x02;     /* enable clock to GPIOB */
    delay = SYSCTL_RCGC2_R;     /* allow time for clock to start */
    delay = delay;

    GPIO_PORTB_DIR_R = 0xFF;    /* set all PORTB pins as output to drive segments */
    GPIO_PORTB_DEN_R = 0xFF;    /* set all PORTB pins as digital pins */
    GPIO_PORTB_DR8R_R = 0xFF;

    GPIO_PORTA_DIR_R = 0xF0;    /* set PORTA pin 7-4 as output to select digit */
    GPIO_PORTA_DEN_R = 0xF0;    /* set PORTA pin 7-4 as digital pins */
    GPIO_PORTA_DR8R_R = 0xF0;

    One_Second_Delay();

    for(;;) {
        for(digits = 0; digits < NO_OF_DIGITS; digits++ ) {
            GPIO_PORTA_DATA_R = digit_no[digits];           /* select digit */

            switch(digits) {
            case 0:
                if( seconds >= 10)
                    minutesec = digitPattern[seconds%10];
                else
                    minutesec = digitPattern[seconds];
                break;
            case 1:
                if( seconds >= 10)
                    minutesec = digitPattern[seconds/10];
                else
                    minutesec = digitPattern[0];
                break;
            case 2:
                if( minutes >= 10)
                    minutesec = digitPattern[minutes%10];
                else
                    minutesec = digitPattern[minutes];
                break;
            case 3:
                if( minutes >= 10)
                    minutesec = digitPattern[minutes/10];
                else
                    minutesec = digitPattern[0];
                break;
            default:
                break;
            }

            /* drive pattern of that number on the segments */
            GPIO_PORTB_DATA_R = minutesec;

            delayMs(1);

            if( (NVIC_ST_CTRL_R & (1<<16) ) != 0) {
                seconds += 1;
                if(seconds >= 59 ) {
                    minutes++;
                    seconds = 0;
                }
                if(minutes >= 59 ) {
                    minutes = 0;
                    seconds = 0;
                }
            }
        }
    }
}

void One_Second_Delay(void)
{
    NVIC_ST_RELOAD_R = 15999999;    /* Reload Value goes here */
    NVIC_ST_CTRL_R |= 0x5;          /* Triggering with external clock */
}

/* delay n milliseconds (16 MHz CPU clock) */
void delayMs(int n)
{
    int i, j;

    for(i = 0 ; i < n; i++)
        for(j = 0; j < 3180; j++)
            {} /* do nothing for 1 ms */
}
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