Arduino Mega ADK R3 Pinout confusion.

Projects Programming
1

I have the Mega ASK R3 board with the Ethernet Shield R3.. I have been working on a sketch for simple LED control. All of my testing has been using the lower pins 2 through 8 while testing functionality. Everything seems to be working correctly when using pins 2 through 8. I tried changing the pin assignments to use pins on the digital header, pins 35 through 42.. The 2560 PinMapping chart indicates where those pins are found on the header but some pins show in the wrong spot and others don't show up at all. Out of the 8 pins, I can only find pins 38 and 39. Pin 38 shows up on header pin 47 and Pin 39 shows up on header pin 27.

Am I missing something very basic? I'm pulling my hair out on this one.

My sketch for reference.

#include <Ethernet.h>
#include <SPI.h>
//network NB: Pins 10, 11, 12 and 13 are reserved for Ethernet module. 
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
byte ip[] = { 192, 168, 1, 177 };
byte gateway[] = { 192, 168, 1, 1 };
byte subnet[] = { 255, 255, 255, 0 };

String inString = String(35);

String Led;

int led[] = {00, 35, 36, 37, 38, 39, 40, 41, 42};
//int led[] = {00, 2, 3, 4, 5, 6, 7, 8};
int numofleds = 42; //numofleds
//String value[] = {"on","on","on","on","on","on","on","on","on"}; //startup all led are off


EthernetServer server(80);
String data;
void setup()
{
  Serial.begin(9600);
  Ethernet.begin(mac, ip,gateway,subnet); 
  server.begin();
 //set pin mode
  for (int j = 35; j < (numofleds + 1); j++){
    pinMode(led[j], OUTPUT);
    digitalWrite(led[j],LOW);
 }
 // for (int k = 45; k < (numofinputs + 1); k++){
 //   pinMode(led[k], INPUT);
 
 
  Serial.println("Serial READY");
  Serial.println("Ethernet READY");
  Serial.println("Server READY");
}

void loop()
{
  EthernetClient client = server.available();
  
  if(client){
    // an http request ends with a blank line
    boolean current_line_is_blank = true;
    while (client.connected()) {
     
      if(client.available()) {
      
        char c = client.read();
        // if we've gotten to the end of the line (received a newline
        // character) and the line is blank, the http request has ended,
        // so we can send a reply
        if (inString.length() < 35) {
            inString.concat(c);
           
         } 
        if (c == '\n' && current_line_is_blank) {
             Serial.println(inString);        
          // send a standard http response header
          client.println("HTTP/1.1 200 OK");
          client.println("Content-Type: text/html");
          client.println();
         // client.println("<html><body><form method=get>");
         // client.println("<p>Led controller</p>");
         
         for(int i = 35; i < (numofleds + 1) ;i++){ 
           Led = String("led") + i;
           
          if(inString.indexOf(Led+"=on")>0 || inString.indexOf("all=on")>0){
            Serial.println(Led+"on");
            digitalWrite(led[i], HIGH);

           // value[i] = "off"; 
          }else if(inString.indexOf(Led+"=off")>0 || inString.indexOf("all=off")>0 ){          
            Serial.println(Led+"off");
            digitalWrite(led[i], LOW);

           // value[i] = "on";
          }
          else if(inString.indexOf(Led+"=status")>0 || inString.indexOf("all=status")>0 ){          
            Serial.println(Led+"status");
            if (digitalRead (led[i]) == 0)  {
              client.println("off");
            }
            else {
              client.println("on");
            break;
        }
        if (c == '\n') {
          // we're starting a new line
          current_line_is_blank = true;
        } else if (c != '\r') {
          // we've gotten a character on the current line
          current_line_is_blank = false;
        }
      }
    }
    // give the web browser time to receive the data
    delay(1);
    inString = "";
    client.stop();
    }
      }
    }

  }
}

Moderator edit: [code] ... [/code] tags added. (Nick Gammon)

2

See how half of the code is in italics?

Please edit your post, select the code, and put it between [code] ... [/code] tags.

You can do that by hitting the # button above the posting area.

Read this before posting a programming question

3 
for (int j = 35; j < (numofleds + 1); j++){
    pinMode(led[j], OUTPUT);
    digitalWrite(led[j],LOW);
 }

The value in numofleds is 42, so this loop will iterate while j is 35, 36, 37, 38, 39, 40, 41, and 42.

But:

int led[] = {00, 35, 36, 37, 38, 39, 40, 41, 42};

Your array only has 9 positions, referenced by 0, 1, 2, 3, 4, 5, 6, 7, and 8.

Your loop is reading non-existent locations of the array, and setting the mode and state of some junk pin number. It is NOT setting the mode and state of the pin you think it is.

If you are going to loop from 35 to 42, you don't need an array of pin numbers. If you are going to use an array, you must loop with the correct indices.

By the way, numodleds is wrong. There are not 42 LEDs. And, you should not have an LED on pin 0.

4

That makes sense, I was being sloppy while working through issues. Thank you Paul..