[SOLVED]LCD 16x2 showing garbage

I'm using the Arduino Ethernet Shield, so CS is pin 10. I get the problem after calling Wire.begin(), and i have no idea how to avoid that, cause I need that to get or set the date from the RTC.

OK, just avoid pin 4 too:

const int chipSelect = 4;

I guess if you use the Ethernet, avoid pin 10 and 4. Since you have RTC on I2C bus, also avoid analog pins 4 and 5 :slight_smile: You don't have many pins left, do you?

Program upload uses 0,1
Ethershield with SD card uses 4,10,11,12,13
RTC uses 18,19 (aka analog 4,5)

So you have left 2,3,5,6,7,8,9,14,15,16,17
You will use 6 of them and have 5 left for the rest of your project, which is what?

but Prueba4 prints like garbage, just random symbols.

It might look like garbage to you but not to others. We have to know exactly what was supposed to be displayed, what was actually displayed, if the correct number of characters were displayed, if the characters are consistent each time, etc.

Don

Don,

I think his/her problem is pin conflict. The pin 4 is used both as chip select for the SD card and the LCD. Let's wait until that is fixed.

This is the last code i tested. I chaged th pins in the LCD to 9,8,7,6,5,3.
I keep getting the same error, it sends correctly Prueba, Prueba1, Prueba2 and Prueba3, but the it calls Wire.begin() everything gets messed up.

#include <LiquidCrystal.h>
#include <SdFat.h>
SdFat sd;
SdFile myFile;
#include "Wire.h"
#define DS1307_I2C_ADDRESS 0x68  // This is the I2C address


// Global Variables
const int chipSelect = 4;
int command = 0;       // This is the command char, in ascii form, sent from the serial port     
int i;
int second, minute, hour, dayOfWeek, dayOfMonth, month, year;
byte test;
byte zero=0x00;
char nombrearchivo[13];
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(9, 8, 7, 6, 5, 3);

// Convert normal decimal numbers to binary coded decimal
byte decToBcd(byte val)
{  return ( (val/10*16) + (val%10) );}

// Convert binary coded decimal to normal decimal numbers
byte bcdToDec(byte val)
{  return ( (val/16*10) + (val%16) );}
 
// 1) Sets the date and time on the ds1307
// 2) Starts the clock
// 3) Sets hour mode to 24 hour clock
// Assumes you're passing in valid numbers, Probably need to put in checks for valid numbers.
// setDateDs1307() solo se necesita una vez, se mantiene el el codigo, por si se debe cambiar la bateria del RTC o modificar la fecha u hora. 
/*void setDateDs1307()                
{
   second = (byte) ((Serial.read() - 48) * 10 + (Serial.read() - 48)); // Use of (byte) type casting and ascii math to achieve result.  
   minute = (byte) ((Serial.read() - 48) *10 +  (Serial.read() - 48));
   hour  = (byte) ((Serial.read() - 48) *10 +  (Serial.read() - 48));
   dayOfWeek = (byte) (Serial.read() - 48);
   dayOfMonth = (byte) ((Serial.read() - 48) *10 +  (Serial.read() - 48));
   month = (byte) ((Serial.read() - 48) *10 +  (Serial.read() - 48));
   year= (byte) ((Serial.read() - 48) *10 +  (Serial.read() - 48));
   Wire.beginTransmission(DS1307_I2C_ADDRESS);
   Wire.write(zero);
   Wire.write(decToBcd(second) & 0x7f);    // 0 to bit 7 starts the clock
   Wire.write(decToBcd(minute));
   Wire.write(decToBcd(hour));      // If you want 12 hour am/pm you need to set
                                   // bit 6 (also need to change readDateDs1307)
   Wire.write(decToBcd(dayOfWeek));
   Wire.write(decToBcd(dayOfMonth));
   Wire.write(decToBcd(month));
   Wire.write(decToBcd(year));
   Wire.endTransmission();
}*/

// Gets the date and time from the ds1307 and prints result
void getDateDs1307()
{
  // Reset the register pointer
  Wire.beginTransmission(DS1307_I2C_ADDRESS);
  Wire.write(zero);
  Wire.endTransmission();
  Wire.requestFrom(DS1307_I2C_ADDRESS, 7);
  // A few of these need masks because certain bits are control bits
  second     = bcdToDec(Wire.read() & 0x7f);
  minute     = bcdToDec(Wire.read());
  hour       = bcdToDec(Wire.read() & 0x3f);  // Need to change this if 12 hour am/pm
  dayOfWeek  = bcdToDec(Wire.read());
  dayOfMonth = bcdToDec(Wire.read());
  month      = bcdToDec(Wire.read());
  year       = bcdToDec(Wire.read());
  
  snprintf(nombrearchivo,13,"%02d%02d20%02d.txt", second, month, year); //merge together
}
 
 
void setup() {
  Serial.begin(9600);
   while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }
  lcd.begin(16, 2);
  lcd.print("Prueba");
  delay(500);
  lcd.clear();
  
  
  // Open serial communications and wait for port to open:
  
  // set up the LCD's number of columns and rows: 
  lcd.print("Prueba1");
  delay(500);
  lcd.clear();
  
  // Initialize SdFat or print a detailed error message and halt
  // Use half speed like the native library.
  // change to SPI_FULL_SPEED for more performance.
  
  lcd.print("Prueba2");
  delay(500);
  lcd.clear();
  
  if (!sd.begin(chipSelect, SPI_HALF_SPEED)) sd.initErrorHalt();
  lcd.print("Prueba3");
  delay(500);
  lcd.clear();
  
  Wire.begin();
  lcd.print("Prueba4");
  delay(500);
  
}
 
void loop() {
     /*if (Serial.available()) {      // Look for char in serial que and process if found
      command = Serial.read();
      if (command == 84 || command == 116) {      //If command = "Tt" Set Date
       //setDateDs1307();
       getDateDs1307();
       
       
       if (!myFile.open(nombrearchivo, O_RDWR | O_CREAT | O_AT_END)) {
        sd.errorHalt("opening test.txt for write failed");
      }
      // if the file is available, write to it:
      Serial.print("Writing to test.txt...");
      myFile.println("testing 1, 2, 3.");

      // close the file:
      myFile.close();
      Serial.println("done.");

      }
      else if (command == 82 || command == 114) {      //If command = "Rr" Read Date ... BBR
       getDateDs1307();
       Serial.println(" ");
      }
      
      Serial.print("Command: ");
      Serial.println(command);     // Echo command CHAR in ascii that was sent
      }
      command = 0;                 // reset command 
      delay(100);*/
      getDateDs1307();
      year+=2000;
      if (!myFile.open(nombrearchivo, O_RDWR | O_CREAT | O_AT_END)) {
        sd.errorHalt("opening test.txt for write failed");
      }
      // if the file is available, write to it:
      Serial.print("Writing");
      lcd.setCursor(0, 0);
      lcd.print("Writing:");
      delay(1000);
      lcd.setCursor(0, 1);
      lcd.print(nombrearchivo);
      myFile.println("testing 1, 2, 3.");
      if(!myFile.timestamp(T_WRITE,year,month,dayOfMonth,hour,minute,second)){
      Serial.println("Mod date failed");
      }
      // close the file:
      myFile.close();
      Serial.println("done.");
      lcd.clear();
      delay(250);
      
      
  }

I'll add some pictures so I can explain myself.

I skipped "Prueba2" and "Prueba3", but they work. I already changed the pins.

From reply #10:
"It might look like garbage to you but not to others. We have to know exactly what was supposed to be displayed, what was actually displayed, if the correct number of characters were displayed, if the characters are consistent each time, etc."
You have responded to one of these points ....

There's no need to clear the LCD each time. Just reposition the cursor and write over the old information.

but Prueba4 prints like garbage, just random symbols.

You haven't shown us this 'garbage' yet.

I think his/her problem is pin conflict. The pin 4 is used both as chip select for the SD card and the LCD. Let's wait until that is fixed.

That could certainly mess up the information on the LCD.

Don

I have been looking at this wrong! This is fellow is using the new leonardo board. Pins 2 and 3 are I2C bus that you use for wire library, avoid these pins instead. All the UNO talk about SPI bus 11,12,13 are irrelavent, except for pin 4 and 10 is still to be avoided. Oh my. Maybe I should get myself a leonardo board now.

That did it, I was using pin 2 for the last bit of the LCD. Thank you very much!

Where can I look at all the pin usage? Maybe this will save me a lot of trouble in the future.

mrescude:
That did it, I was using pin 2 for the last bit of the LCD. Thank you very much!

Where can I look at all the pin usage? Maybe this will save me a lot of trouble in the future.

Look at the middle of the page "input and output". For shields, you should be able to find pin usage where you buy them.

What happened today is a good thing for me. As a shield designer I should have looked at Leonardo. Now that I have, I'll spend some time thinking what to do with my shield update, especially with pins 2 and 3 now.

Well, just in case anyone wants to see the working code... I just changed the pin usage in the LCD to LiquidCrystal lcd(13,12,11,9,8,7),

#include <LiquidCrystal.h>
#include <SdFat.h>
SdFat sd;
SdFile myFile;
#include "Wire.h"
#define DS1307_I2C_ADDRESS 0x68  // This is the I2C address


// Global Variables
const int chipSelect = 4;
int command = 0;       // This is the command char, in ascii form, sent from the serial port     
int i;
int second, minute, hour, dayOfWeek, dayOfMonth, month, year;
byte test;
byte zero=0x00;
char nombrearchivo[13];
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(13,12, 11, 9, 8, 7);

// Convert normal decimal numbers to binary coded decimal
byte decToBcd(byte val)
{  return ( (val/10*16) + (val%10) );}

// Convert binary coded decimal to normal decimal numbers
byte bcdToDec(byte val)
{  return ( (val/16*10) + (val%16) );}
 
// 1) Sets the date and time on the ds1307
// 2) Starts the clock
// 3) Sets hour mode to 24 hour clock
// Assumes you're passing in valid numbers, Probably need to put in checks for valid numbers.
// setDateDs1307() solo se necesita una vez, se mantiene el el codigo, por si se debe cambiar la bateria del RTC o modificar la fecha u hora. 
/*void setDateDs1307()                
{
   second = (byte) ((Serial.read() - 48) * 10 + (Serial.read() - 48)); // Use of (byte) type casting and ascii math to achieve result.  
   minute = (byte) ((Serial.read() - 48) *10 +  (Serial.read() - 48));
   hour  = (byte) ((Serial.read() - 48) *10 +  (Serial.read() - 48));
   dayOfWeek = (byte) (Serial.read() - 48);
   dayOfMonth = (byte) ((Serial.read() - 48) *10 +  (Serial.read() - 48));
   month = (byte) ((Serial.read() - 48) *10 +  (Serial.read() - 48));
   year= (byte) ((Serial.read() - 48) *10 +  (Serial.read() - 48));
   Wire.beginTransmission(DS1307_I2C_ADDRESS);
   Wire.write(zero);
   Wire.write(decToBcd(second) & 0x7f);    // 0 to bit 7 starts the clock
   Wire.write(decToBcd(minute));
   Wire.write(decToBcd(hour));      // If you want 12 hour am/pm you need to set
                                   // bit 6 (also need to change readDateDs1307)
   Wire.write(decToBcd(dayOfWeek));
   Wire.write(decToBcd(dayOfMonth));
   Wire.write(decToBcd(month));
   Wire.write(decToBcd(year));
   Wire.endTransmission();
}*/

// Gets the date and time from the ds1307 and prints result
void getDateDs1307()
{
  // Reset the register pointer
  Wire.beginTransmission(DS1307_I2C_ADDRESS);
  Wire.write(zero);
  Wire.endTransmission();
  Wire.requestFrom(DS1307_I2C_ADDRESS, 7);
  // A few of these need masks because certain bits are control bits
  second     = bcdToDec(Wire.read() & 0x7f);
  minute     = bcdToDec(Wire.read());
  hour       = bcdToDec(Wire.read() & 0x3f);  // Need to change this if 12 hour am/pm
  dayOfWeek  = bcdToDec(Wire.read());
  dayOfMonth = bcdToDec(Wire.read());
  month      = bcdToDec(Wire.read());
  year       = bcdToDec(Wire.read());
  
  snprintf(nombrearchivo,13,"%02d%02d20%02d.txt", second, month, year); //merge together
}
 
 
void setup() {
  Serial.begin(9600);
   while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }
  // set up the LCD's number of columns and rows:  
  lcd.begin(16, 2);
  
  lcd.print("Inicializando...");
  delay(1000);
  lcd.clear();
  // Initialize SdFat or print a detailed error message and halt
  // Use half speed like the native library.
  // change to SPI_FULL_SPEED for more performance.
  
    if (!sd.begin(chipSelect, SPI_HALF_SPEED)){ 
      sd.initErrorHalt();
      lcd.print("SD Error!!!     ");
  
  }
  else{lcd.print("SD Lista!!!     "); }
  delay(500);
  lcd.clear();
  Wire.begin();
  lcd.print("Sist Preparado!!");
  delay(500);
  
}
 
void loop() {
     /*if (Serial.available()) {      // Look for char in serial que and process if found
      command = Serial.read();
      if (command == 84 || command == 116) {      //If command = "Tt" Set Date
       //setDateDs1307();
       getDateDs1307();
       
       
       if (!myFile.open(nombrearchivo, O_RDWR | O_CREAT | O_AT_END)) {
        sd.errorHalt("opening test.txt for write failed");
      }
      // if the file is available, write to it:
      Serial.print("Writing to test.txt...");
      myFile.println("testing 1, 2, 3.");

      // close the file:
      myFile.close();
      Serial.println("done.");

      }
      else if (command == 82 || command == 114) {      //If command = "Rr" Read Date ... BBR
       getDateDs1307();
       Serial.println(" ");
      }
      
      Serial.print("Command: ");
      Serial.println(command);     // Echo command CHAR in ascii that was sent
      }
      command = 0;                 // reset command 
      delay(100);*/
      getDateDs1307();
      year+=2000;
      if (!myFile.open(nombrearchivo, O_RDWR | O_CREAT | O_AT_END)) {
        sd.errorHalt("opening test.txt for write failed");
      }
      // if the file is available, write to it:
      Serial.print("Writing");
      lcd.setCursor(0, 0);
      lcd.print("Escribiendo:    ");
      lcd.setCursor(0, 1);
      lcd.print(nombrearchivo);
      myFile.println("testing 1, 2, 3.");
      if(!myFile.timestamp(T_WRITE,year,month,dayOfMonth,hour,minute,second)){
      Serial.println("Mod date failed");
      }
      // close the file:
      myFile.close();
      Serial.println("done.");
      
      delay(500);
      
      
  }

Thank you! I couldn't have done it without your help.

For shields, you should be able to find pin usage where you buy them.

How about here: --> http://shieldlist.org/

Don

floresta:

For shields, you should be able to find pin usage where you buy them.

How about here: --> http://shieldlist.org/

Don

A good starting point but not the most updated list I wish it would be. Most of my shields aren't listed :wink:

Most of my shields aren't listed...

Did you scroll down the page?
"If you know of a shield that needs to be added, please tell me about it!"

On the other hand you probably did.
"There are currently 285 shields submitted that I haven't got to processing yet. Sorry!"

That's not too good considering there are only 288 listed. Maybe he has a day job.

Don

floresta:

Most of my shields aren't listed...

Did you scroll down the page?
"If you know of a shield that needs to be added, please tell me about it!"

On the other hand you probably did.
"There are currently 285 shields submitted that I haven't got to processing yet. Sorry!"

That's not too good considering there are only 288 listed. Maybe he has a day job.

Don

I requested but he was probably too busy.

Folks,
I'm having the same problem. I have a shield with combined RTC and SD card. I've wired up the LCD (16 x 2) and it works perfectly when I use the simple sample code for the LCD. I've noticed that it also works fine when I integrate the code into my program which utilizes the RTC and SD card IF AND ONLY IF I write to the LCD before initializing the SD or RTC. Actually, I saw the comments about SPI conflicts etc, so I modified the pins for the LCD a few times and found that in the original configuration, I could write to the LCD successfully AFTER the RTC initialization, but not after the SD card. Then, after I switched the pins, and it ONLY works if I write to the LCD at the beginning of the Setup() function before both RTC and SD calls. I thought I understood the potential conflicts so I've wired the LCD to pins as follows:

LiquidCrystal lcd(7,8,9,6,5,0);

This doesn't seem to be using any pins that conflict, but maybe I'm missing something? I have an Uno and am also using pins 2-4 for an optical sensor so they are not avail. Thoughts on how to resolve the conflict? Oh, the problem I'm having is that any writes to the LCD are correct ahead of the RTC/SD initializations, but I get gibberish when I write after those calls.
Thanks,
Cameron

Are you using the SD slot in the ethernet shield? If so, the SD chip select is pin 4, that could be causing your problems.

LiquidCrystal lcd(7,8,9,6,5,0);

Are you going to keep us in the dark about your code? For example, are you using the Serial Monitor?

By the way, you tacked this on to an old thread that is marked [SOLVED], not really a good idea.

Don

Thanks guys. Yes. I'm using the SD card, the Serial Monitor and the RTC. Everything works fine if I leave out the code for the LCD, so I don' t see how pin 4 might be conflicting with my optical sensor. I also thought that the chipselect was pin 10. Here is the code.

 #include "SD.h"
#include <Wire.h>
#include "RTClib.h"
#include <LiquidCrystal.h>

//These define the pin connections of the Arduino.  
//They can be changed but only use digital in 2 or 3 for the Freq pin
#define TSL_FREQ_PIN 2 // output use digital pin2 for interrupt

float fD = 0.1; // Dark frequency
float Re = 2.3; // Irradiance responsivity
float eff475 = 0.113; // Luminous efficiency at 475nm, for dinoflagellate bioluminescence

RTC_DS1307 RTC; // define the Real Time Clock object

#define ECHO_TO_SERIAL   1 // echo data to serial port
#define WAIT_TO_START    0 // Wait for serial input in setup()

// the digital pins that connect to the LEDs
#define redLEDpin 3
#define greenLEDpin 4

// for the data logging shield, we use digital pin 10 for the SD cs line
const int chipSelect = 10;

// the logging file
File logfile;

void error(char *str)
{
  Serial.print("error: ");
  Serial.println(str);
  
  // red LED indicates error
  digitalWrite(redLEDpin, HIGH);
  
  while(1);
}

int timing = 1000; // in milliseconds
volatile unsigned long pulse_cnt = 0;

 // initialize the library with the numbers of the interface pins
LiquidCrystal lcd(7,8,9,6,5,0);

void setup() {
   // IF I PUT THE LCD CODE HERE, IT WORKS FINE (see bottom)

  Serial.begin(9600);
  Serial.println();
  Wire.begin();
  RTC.begin();

#if WAIT_TO_START
  Serial.println("Type any character to start");
  while (!Serial.available());
#endif //WAIT_TO_START

  Serial.print("Initializing SD card...");
  // make sure that the default chip select pin is set to
  // output, even if you don't use it:
  pinMode(chipSelect, OUTPUT);
  
  // see if the card is present and can be initialized:
  if (!SD.begin(chipSelect)) {
    Serial.println("Card failed, or not present");
    // don't do anything more:
    return;
  }
  Serial.println("card initialized.");
// PROBLEM CODE IS HERE:
    // set up the LCD's number of columns and rows: 
  lcd.begin(16, 2);
 lcd.setCursor(0, 0);
  // Print a message to the LCD.
 lcd.print("LCD not working!");

Thanks guys. Yes. I'm using the SD card, the Serial Monitor and the RTC.

It is probably the Serial Monitor and the LCD competing for the use of pin 0.

Don