Running Serial and LCD in Tandem

Projects Programming
1

I am trying to run serial and LCD in the setup function. Here is my code:

void setup()
{
  Serial.begin(9600);

  // set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
  // Print a message to the LCD.
  lcd.print("hello, world!");
}

On my LCD, I am not seeing anything. I can provide my full code, if need be. Just wasn't sure why these would be conflicting.

2

The problem is in the code you didn't post. Where is the declaration for lcd? Which library is this using?

Is this a serial LCD? You didn't actually say. But yes, in general, trying to run a serial LCD and the Serial Monitor won't work on many Arduinos. The Due, Leonardo, Micro and Teensy don't have this problem.

3 
/*4x4 Matrix Keypad connected to Arduino
  This code prints the key pressed on the keypad to the serial port*/

#include <Keypad.h>
using namespace std;
#include <LiquidCrystal.h>

LiquidCrystal lcd(1, 0, 13, 12, 11, 10);
const byte numRows = 4; //number of rows on the keypad
const byte numCols = 4; //number of columns on the keypad
int numChars = 0;

//keymap defines the key pressed according to the row and columns just as appears on the keypad
char keymap[numRows][numCols] =
{
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

//Code that shows the the keypad connections to the arduino terminals
byte rowPins[numRows] = {9, 8, 7, 6}; //Rows 0 to 3
byte colPins[numCols] = {5, 4, 3, 2}; //Columns 0 to 3

//initializes an instance of the Keypad class
Keypad myKeypad = Keypad(makeKeymap(keymap), rowPins, colPins, numRows, numCols);

void setup()
{
  Serial.begin(9600);

// set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
  // Print a message to the LCD.
  lcd.print("hello, world!");
}

//If key is pressed, this key is stored in 'keypressed' variable
//If key is not equal to 'NO_KEY', then this key is printed out
//if count=17, then count is reset back to 0 (this means no key is pressed during the whole keypad scan process
void loop()
{
  // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 1);
  // print the number of seconds since reset:
  lcd.print(millis() / 1000);
  
  char keypressed = myKeypad.getKey();
  char keys[5];

  if (keypressed != NO_KEY)
  {
    Serial.print(keypressed);
    keys[numChars] = keypressed;
    numChars++;
    
  }
}
5

Was afraid of that... so that leads me to another question....

I have no more Digital ports left on my uno. Many are already being used by a keypad. Is there any way to expand this, or do I need to upgrade to a different device to be able to use both the keypad and the LCD?

6

Use the analog pins; they can be used as digital IO.