Testing Logic Gates using Arduino

Question

hello guys is there someone who can help me with my first project. its basically about logic circuits.

by using tact switch and pull-up resistor to set the values to logical 1 or 0. the output can be verified by using a LED as an indicator. so the code goes like this:

//AND GATE          
int pin2=1;         //set pin2=1
int pin3=1;         //set pin3=1

void setup()
{
pinMode(2,INPUT);
pinMode(3,INPUT);
pinMode(4,OUTPUT);
pinMode(11,OUTPUT);    
pinMode(12,OUTPUT);
}
void loop()
{
  pin2=digitalRead(2);
  pin3=digitalRead(3);

 if(pin2==1)            //turn led on pin11 when pin2 =1
 {
 digitalWrite(11,HIGH);
 }
 else
 {
 digitalWrite(11,LOW);
 }

 if(pin3==1)          ////turn led on pin12 when pin3 =1
 {
   digitalWrite(12,HIGH);
 }
 else
 {
   digitalWrite(12,LOW);
 }

//TRUTH TABLE OF AND 

  if(pin2 && pin3)       
  {
    digitalWrite(4,HIGH);
  }
  else
  {
  digitalWrite(4,LOW);
  }
}

//OR GATE          
int pin2=1;
int pin3=1;

void setup()
{
pinMode(2,INPUT);
pinMode(3,INPUT);
pinMode(4,OUTPUT);
pinMode(11,OUTPUT);
pinMode(12,OUTPUT);
}
void loop()
{
  pin2=digitalRead(2);
  pin3=digitalRead(3);

 if(pin2==1)            
 {
 digitalWrite(11,HIGH);
 }
 else
 {
 digitalWrite(11,LOW);
 }

 if(pin3==1)          
 {
   digitalWrite(12,HIGH);
 }
 else
 {
   digitalWrite(12,LOW);
 }

//TRUTH TABLE OF OR 

  if(pin2 || pin3)       
  {
    digitalWrite(4,HIGH);
  }
  else
  {
  digitalWrite(4,LOW);
  }
}

//NAND GATE          
int pin2=1;
int pin3=1;

void setup()
{
pinMode(2,INPUT);
pinMode(3,INPUT);
pinMode(4,OUTPUT);
pinMode(11,OUTPUT);
pinMode(12,OUTPUT);
}
void loop()
{
  pin2=digitalRead(2);
  pin3=digitalRead(3);

 if(pin2==1)            
 {
 digitalWrite(11,HIGH);
 }
 else
 {
 digitalWrite(11,LOW);
 }

 if(pin3==1)          
 {
   digitalWrite(12,HIGH);
 }
 else
 {
   digitalWrite(12,LOW);
 }

//TRUTH TABLE OF NAND 

  if(!(pin2 && pin3))       
  {
    digitalWrite(4,HIGH);
  }
  else
  {
  digitalWrite(4,LOW);
  }
}

can you guys help me to run this in one sketch by using tact switch to select the logic gate to be tested or run? thank you in advance

Answer 1

What about something like this:

const uint8_t    inA =  2;
const uint8_t    inB =  3;
const uint8_t   outA =  4;
const uint8_t   outB = 11;
const uint8_t   outY = 12;
const uint8_t button =  5;

void setup() {
    pinMode(inA, INPUT_PULLUP);
    pinMode(inB, INPUT_PULLUP);
    pinMode(outA, OUTPUT);
    pinMode(outB, OUTPUT);
    pinMode(outY, OUTPUT);

    pinMode(button, INPUT_PULLUP);
}

uint32_t check_time = 0;

uint8_t     counter = 0;
uint8_t       funct = 0b0110; // start with XOR  

void loop() {
    // active low: (for usage with buttons connected to ground with internal pullup)
    // uint8_t state = (digitalRead(inA)==LOW) | (digitalRead(inB)==LOW)<<1;

    // active high:
    uint8_t state = (digitalRead(inA)==HIGH) | (digitalRead(inB)==HIGH)<<1;

    digitalWrite(outA, (state & 1) > 0);
    digitalWrite(outB, (state & 2) > 0);

    digitalWrite(outY, ((funct >> state) & 1) > 0);


    // button handling
    uint32_t actual = millis();
    if (actual > check_time) {
        check_time = actual + 4; // check every 4ms

        if (digitalRead(button) == LOW) { // expects pull-up and active low
            if (++counter == 4) { // debounce - confirmed after 16ms (4*4) and every 256*4 ms again
                funct = (funct + 1) & 0xF;
            }
        } else {
            counter = 0; // reset counter
        }
    }
}

It uses push button to cycle through all 16 possible functions of two inputs. Default is XOR. Assumption is Active HIGH inputs (you can use INPUT instead of INPUT_PULLUP).

Answer 2

For simulating different gates with the same program, an option is to use the serial port to tell it what gate you want it to simulate. Here I am also using a function pointer (called gate) to represent the selected gate:

/* Wiring. */
const int inputA    = 2;
const int inputB    = 3;
const int outputA   = 11;
const int outputB   = 12;
const int outputRes = 4;

void setup()
{
    pinMode(inputA,    INPUT_PULLUP);
    pinMode(inputB,    INPUT_PULLUP);
    pinMode(outputA,   OUTPUT);
    pinMode(outputB,   OUTPUT);    
    pinMode(outputRes, OUTPUT);
    Serial.begin(9600);
    Serial.println(F("Type 'a'(for AND), 'o' (OR) or 'n' (NAND)."));
}

/* Available gates. */
bool AND(bool a, bool b)  { return a && b; }
bool OR(bool a, bool b)   { return a || b; }
bool NAND(bool a, bool b) { return !(a && b); }

/* The gate we want to test. */
bool (*gate)(bool a, bool b) = AND;

void loop()
{
    // Select the gate through the serial port.
    switch (Serial.read()) {
        case 'a': gate = AND;  Serial.println("AND");  break;
        case 'o': gate = OR;   Serial.println("OR");   break;
        case 'n': gate = NAND; Serial.println("NAND"); break;
    }

    // Simulate the gate.
    bool a = !digitalRead(inputA);  // input is in negative logic
    bool b = !digitalRead(inputB);
    digitalWrite(outputA, a);
    digitalWrite(outputB, b);
    digitalWrite(outputRes, gate(a, b));
}

Here is another version, that uses an enum instead of a function pointer to identify the gate. The constants and the setup() are the same as before, then:

void loop()
{
    // The gate we want to test.
    static enum { AND, OR, NAND } gate;

    // Select the gate through the serial port.
    switch (Serial.read()) {
        case 'a': gate = AND;  Serial.println("AND");  break;
        case 'o': gate = OR;   Serial.println("OR");   break;
        case 'n': gate = NAND; Serial.println("NAND"); break;
    }

    // Simulate the gate.
    bool a = !digitalRead(inputA);  // input is in negative logic
    bool b = !digitalRead(inputB);
    digitalWrite(outputA, a);
    digitalWrite(outputB, b);
    bool res = false;
    switch (gate) {
        case AND:  res = a && b;    break;
        case OR:   res = a || b;    break;
        case NAND: res = !(a && b); break;
    }
    digitalWrite(outputRes, res);
}