[Arduino] Using 74LS48 decoder and 7 -segment to display number

[Arduino] Using 74LS48 decoder and 7 -segment to display number

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Document :

PDF file 74LS48 Spec



XL-SD105602 - 0.56-inch Single Digit LED 7-Segment Display

According to PDF (74LS48 -- common cathode) and Single Digit LED 7-segment Display.

Connect Output a to LED a. LED a pin location is 7. 74LS48 output a is pin 13.

Connect Output b to LED b. LED b pin location is 6. 74LS48 output b is pin 12.

Connect Output c to LED c. LED c pin location is 4. 74LS48 output c is pin 11.

Connect Output d to LED d. LED d pin location is 2. 74LS48 output d is pin 10.

Connect Output e to LED e. LED e pin location is 1. 74LS48 output e is pin 9.

Connect Output f  to LED f.  LED f pin location is 9. 74LS48 output f is pin 15.

Connect Output g to LED g. LED g pin location is 10. 74LS48 output g is pin 14.



Connect Input A to Arduino Digital pin 2.

Connect Input B to Arduino Digital pin 3.

Connect Input C  to Arduino Digital pin 4.

Connect Input D to Arduino Digital pin 5



Because my Digit LED 7-segment Display is common cathode. 

So 74LS48 GND is pin 8. Let the pin 8 connect to GND of arduino. That will make the LED blink, other connect to VCC won't blink.





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/*

  Blink

  Turns on an LED on for one second, then off for one second, repeatedly.

 

  This example code is in the public domain.

 */

 

// Pin 13 has an LED connected on most Arduino boards.

// give it a name:







#define led2 2

#define led3 3

#define led4 4

#define led5 5





// Pins for A B C D E F G, in sequence

const int segs[4] = { led2, led3, led4, led5};





// Segments that make each number

const byte numbers[10] = {0b0000, 0b0001, 0b0010, 0b0011, 0b0100, 0b0101, 0b0110, 0b0111, 0b1000, 0b1001};



// the setup routine runs once when you press reset:

void setup() {                

  // initialize the digital pin as an output.

  pinMode(led2, OUTPUT);     

  pinMode(led3, OUTPUT);  

  pinMode(led4, OUTPUT);  

  pinMode(led5, OUTPUT);    

}



// the loop routine runs over and over again forever:

void loop() {

  for ( int i = 1 ; i <= 9 ; i++)

  {

    lightSegments(numbers[0]);  

    NolightSegments(numbers[0]);  

  }



 



}





void lightSegments(byte number) {

  for (int i = 0; i < 4; i++) {

    int bit = bitRead(number, i);

    digitalWrite(segs[i], bit);

  }

}



void NolightSegments(byte number) {

  for (int i = 0; i < 4; i++) {

    digitalWrite(segs[i], LOW);

  }

}



//  digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)

//  delay(1000);               // wait for a second

//  digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW

//  delay(1000);