2017-09-06 - Cable Tester with Port Expander

#include "Wire.h"
#include "Adafruit_MCP23017.h"

enum {PASS, FAIL_NOTCONNECTED, FAIL_WRONGCONNECTED, FAIL_SHORTENED };

// pin numbers for use at begin and end of cable
const byte pinsCableBegin[]= { 2, 3, 4, 5, 6, 7};//, 8, 9, 10, 11, 12, 13};
const byte pinsCableEnd[]  = {A0,A1,A2,A3,A4,A5};//, 21, 22, 23, 24,25,26};

const byte NUMCABLES=sizeof(pinsCableBegin);

Adafruit_MCP23017 mcp;

void setup() {

  Serial.begin(9600);

  mcp.begin();
  Wire.begin();
  Wire.beginTransmission(0x20);
  Wire.write(0x00);	//GPIOA
  Wire.write(0x00); //Sets all of bank A as outputs


  if (sizeof(pinsCableBegin)!=sizeof(pinsCableEnd))
  {
    Serial.println("Pin configuration Error.");
    Serial.println("Fix declaration of pinsCableBegin[] and pinsCableEnd[] arrays!");
    while(1); // error stop with endless loop
  }
  Serial.println();
  Serial.println("################################################");
  Serial.println("#                CABLE TESTER                  #");
  Serial.println("################################################");
  Serial.println();
}

void allPinsInputHigh()
{ // set all pins to INPUT_PULLUP in a for-loop
  for (byte i=0;i<NUMCABLES;i++)
  {
    pinMode(pinsCableBegin[i],INPUT_PULLUP); //enables internal 20k pullup resistors
    pinMode(pinsCableEnd[i],INPUT_PULLUP);
    //mcp.pinMode(pinsCableEnd[i], INPUT); //
    //mcp.pullUp(pinsCableEnd[i], HIGH); //
  }
}


void DoOneTest()
{
  byte result;
  Serial.println();
  Serial.println("### TEST ###");
  for (byte i=0;i<NUMCABLES;i++) // test each pin
  {
    result= PASS; // initially there is no error found, assume PASS
    allPinsInputHigh();
    // first test is for continuity and OUTPUT/HIGH
    pinMode(pinsCableBegin[i], OUTPUT);
    if (digitalRead(pinsCableEnd[i])!=HIGH)
    {
        bitSet(result,FAIL_NOTCONNECTED);
    }
    // then check for continuity and OUTPUT/LOW
    digitalWrite(pinsCableBegin[i], LOW);
    if (digitalRead(pinsCableEnd[i])!=LOW)
    {
        bitSet(result,FAIL_NOTCONNECTED);
    }

    // next test: check for wrong connections to other pins
    for (byte j=0;j<NUMCABLES;j++)
    {
      if (j!=i && digitalRead(pinsCableEnd[j])==LOW)
      {
        bitSet(result, FAIL_WRONGCONNECTED);
      }
    }

    Serial.print("Line ");
    Serial.print(i+1);
    if (result== PASS) Serial.print(" PASS");
    else Serial.print(" FAIL");
    if (bitRead(result,FAIL_NOTCONNECTED)) Serial.print(" BREAK");
    if (bitRead(result,FAIL_WRONGCONNECTED)) Serial.print(" WRONG");
    if  (bitRead(result,FAIL_SHORTENED)) Serial.print(" SHORT");
    Serial.println();
  }
  Serial.println("Test finished.");
  Serial.println();
}

void loop() {
  if (Serial.available())
  {
    DoOneTest();
    delay(20);
    while (Serial.available()) Serial.read(); // clear Serial input buffer
  }
}