I got this code from https://github.com/paltrickontpb/Digital_IC_Tester_74xx/blob/master/Gate_Tester_74xx/Gate_Tester_74xx.ino

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1

Does anyone know how i can change the pins so that i can also test for IC 7401 , cause the input and output pins are different

//Digital IC Tester for 74xx Series IC
//By Projjal Gupta & Shreyas

#include <String.h>

//Initializing Input and Output pins
int ip1 = 2;
int ip2 = 3;
int ip3 = 4;
int ip4 = 5;
int ip5 = 6;
int ip6 = 7;
int ip7 = 8;
int ip8 = 9;

int op1 = A0;
int op2 = A1;
int op3 = A2;
int op4 = A3;

String datainput = "";

void setup() {

  // Initializing the type of pin activity
  pinMode(ip1,OUTPUT); 
  pinMode(ip2,OUTPUT);
  pinMode(ip3,OUTPUT);
  pinMode(ip4,OUTPUT);
  pinMode(ip5,OUTPUT);
  pinMode(ip6,OUTPUT);
  pinMode(ip7,OUTPUT);
  pinMode(ip8,OUTPUT);
  
  pinMode(op1,INPUT);//IC pin 3
  pinMode(op2,INPUT);//IC pin 6
  pinMode(op3,INPUT);//IC pin 8
  pinMode(op4,INPUT);//IC pin 11

  Serial.begin(9600);

}

void normalPin(){
  digitalWrite(ip1, LOW);//IC pin 1
  digitalWrite(ip2, LOW);//IC pin 2
  
  digitalWrite(ip3, LOW);//IC pin 4
  digitalWrite(ip4, HIGH);//IC pin 5

  digitalWrite(ip5, HIGH);//IC pin 9
  digitalWrite(ip6, LOW);//IC pin 10

  digitalWrite(ip7, HIGH);//IC pin 12
  digitalWrite(ip8, HIGH);//IC pin 13
}

void TypeTest(String num) { 
  
  //Read the output of the Gates
  int a = digitalRead(op1);
  int b = digitalRead(op2);
  int c = digitalRead(op3);
  int d = digitalRead(op4);

  if (num == "7408") {
    normalPin();
    if (a==0){
      Serial.println("Gate 1 OK");
    } else {
      Serial.println("Gate 1 Not OK");
    }
    if (b==0){
      Serial.println("Gate 2 OK");
    } else {
      Serial.println("Gate 2 Not OK");
    }
    if (c==0){
      Serial.println("Gate 3 OK");
    } else {
      Serial.println("Gate 3 Not OK");
    }
    if (d==1){
      Serial.println("Gate 4 OK");
    } else {
      Serial.println("Gate 4 Not OK");
    }
  } else if (num == "7432") {
    normalPin();
    if (a==0){
      Serial.println("Gate 1 OK");
    } else {
      Serial.println("Gate 1 Not OK");
    }
    if (b==1){
      Serial.println("Gate 2 OK");
    } else {
      Serial.println("Gate 2 Not OK");
    }
    if (c==1){
      Serial.println("Gate 3 OK");
    } else {
      Serial.println("Gate 3 Not OK");
    }
    if (d==1){
      Serial.println("Gate 4 OK");
    } else {
      Serial.println("Gate 4 Not OK");
    }
  } else if (num == "7400") {
    normalPin();
    if (a==1){
      Serial.println("Gate 1 OK");
    } else {
      Serial.println("Gate 1 Not OK");
    }
    if (b==1){
      Serial.println("Gate 2 OK");
    } else {
      Serial.println("Gate 2 Not OK");
    }
    if (c==1){
      Serial.println("Gate 3 OK");
    } else {
      Serial.println("Gate 3 Not OK");
    }
    if (d==0){
      Serial.println("Gate 4 OK");
    } else {
      Serial.println("Gate 4 Not OK");
    }
  } else if (num == "7486") {
    normalPin();
    if (a==0){
      Serial.println("Gate 1 OK");
    } else {
      Serial.println("Gate 1 Not OK");
    }
    if (b==1){
      Serial.println("Gate 2 OK");
    } else {
      Serial.println("Gate 2 Not OK");
    }
    if (c==1){
      Serial.println("Gate 3 OK");
    } else {
      Serial.println("Gate 3 Not OK");
    }
    if (d==0){
      Serial.println("Gate 4 OK");
    } else {
      Serial.println("Gate 4 Not OK");
    }
  } else {
    Serial.println("Invalid Input");
  }
}
void loop() { //Main Function that continuously loops
  Serial.println("================================================");
  Serial.println("================================================");
  Serial.println("===        DIGITAL IC TESTER CIRCUIT         ===");
  Serial.println("================================================");
  Serial.println("================================================");
  Serial.println("========   BY PROJJAL GUPTA & SHREYAS   ========");
  Serial.println("================================================");
  Serial.println("================================================");
  Serial.println("================================================");
  Serial.println("        TYPE IN THE IC NUMBER FOR TESTING       ");
  Serial.println("================================================");
  Serial.println("");
  Serial.println("");
  Serial.println("IC NUMBER :");

  datainput = Serial.readString();
  TypeTest(datainput);
}```
3

That chip requires pullup resistors on the open-collector outputs.

For that chip you'll have to rewrite almost the whole program. You better look for valid code, this one has serious flaws. E.g. normalPin() should be called before testing the outputs or the tests will never succeed.

See the Related Topics below.