Arduino Mega + DS18B20 + TFT

I can’t get my program to print temperature on TFT.

#include <DallasTemperature.h>
#include <OneWire.h>
#include <Adafruit_GFX.h> // Core graphics library
#include <Adafruit_TFTLCD.h> // Hardware-specific library

#define LCD_CS A3 // Chip Select goes to Analog 3
#define LCD_CD A2 // Command/Data goes to Analog 2
#define LCD_WR A1 // LCD Write goes to Analog 1
#define LCD_RD A0 // LCD Read goes to Analog 0

#define LCD_RESET A4 // Can alternately just connect to Arduino’s reset pin

// Assign human-readable names to some common 16-bit color values:
#define BLACK 0x0000
#define BLUE 0x001F
#define RED 0xF800
#define GREEN 0x07E0
#define CYAN 0x07FF
#define MAGENTA 0xF81F
#define YELLOW 0xFFE0
#define WHITE 0xFFFF

Adafruit_TFTLCD tft(LCD_CS, LCD_CD, LCD_WR, LCD_RD, LCD_RESET);

// OneWire DS18S20, DS18B20, DS1822 Temperature Example
//
// http://www.pjrc.com/teensy/td_libs_OneWire.html
//
// The DallasTemperature library can do all this work for you!
// http://milesburton.com/Dallas_Temperature_Control_Library

OneWire ds(22); // on pin 22 (a 4.7K resistor is necessary)

void setup(void) {
Serial.begin(9600);
tft.reset();
}

void loop(void) {

byte i;
byte present = 0;
byte type_s;
byte data[12];
byte addr[8];
float celsius, fahrenheit;

if ( !ds.search(addr)) {
Serial.println(“No more addresses.”);
Serial.println();
ds.reset_search();
delay(2500);
return;
}

Serial.print(“ROM =”);
for( i = 0; i < 8; i++) {
Serial.write(’ ');
Serial.print(addr*, HEX);*

  • }*

  • if (OneWire::crc8(addr, 7) != addr[7]) {*

  • Serial.println(“CRC is not valid!”);*

  • return;*

  • }*

  • Serial.println();*

  • // the first ROM byte indicates which chip*

  • switch (addr[0]) {*

  • case 0x10:*

  • Serial.println(" Chip = DS18S20"); // or old DS1820*

  • type_s = 1;*

  • break;*

  • case 0x28:*

  • Serial.println(" Chip = DS18B20");*

  • type_s = 0;*

  • break;*

  • case 0x22:*

  • Serial.println(" Chip = DS1822");*

  • type_s = 0;*

  • break;*

  • default:*

  • Serial.println(“Device is not a DS18x20 family device.”);*

  • return;*

  • }*

  • ds.reset();*

  • ds.select(addr);*

  • ds.write(0x44, 1); // start conversion, with parasite power on at the end*

  • delay(2500); // maybe 750ms is enough, maybe not*

  • // we might do a ds.depower() here, but the reset will take care of it.*

  • present = ds.reset();*

  • ds.select(addr); *

  • ds.write(0xBE); // Read Scratchpad*

  • Serial.print(" Data = ");*

  • Serial.print(present, HEX);*

  • Serial.print(" ");*

  • for ( i = 0; i < 9; i++) { // we need 9 bytes*
    _ data = ds.read();_
    _ Serial.print(data*, HEX);
    Serial.print(" “);
    }
    Serial.print(” CRC=");
    Serial.print(OneWire::crc8(data, 8), HEX);
    Serial.println();
    // Convert the data to actual temperature*
    * // because the result is a 16 bit signed integer, it should*
    * // be stored to an “int16_t” type, which is always 16 bits*
    * // even when compiled on a 32 bit processor._
    int16_t raw = (data[1] << 8) | data[0];
    if (type_s) {
    _ raw = raw << 3; // 9 bit resolution default*
    * if (data[7] == 0x10) {
    // “count remain” gives full 12 bit resolution*
    * raw = (raw & 0xFFF0) + 12 - data[6];
    }
    } else {
    byte cfg = (data[4] & 0x60);
    // at lower res, the low bits are undefined, so let’s zero them*
    * if (cfg == 0x00) raw = raw & ~7; // 9 bit resolution, 93.75 ms*
    * else if (cfg == 0x20) raw = raw & ~3; // 10 bit res, 187.5 ms*
    * else if (cfg == 0x40) raw = raw & ~1; // 11 bit res, 375 ms*
    * //// default is 12 bit resolution, 750 ms conversion time*
    * }*_

* celsius = (float)raw / 16.0;*
_ fahrenheit = celsius * 1.8 + 32.0;
* Serial.print(" Temperature = “);
Serial.print(celsius);
Serial.print(” Celsius, “);
Serial.print(fahrenheit);
Serial.println(” Fahrenheit");
testText();
}
unsigned long testText() {
tft.setCursor(0, 0);
tft.setTextColor(BLACK); tft.setTextSize(3);
tft.println(“1.Temp:”);
tft.setCursor(135, 0);
tft.println(“140”);*_

}

Maybe the compiler didn't like the italics

I guess there are two issues, only one of which need be a problem.

  1. The temperature code is suss
  2. the display code is suss

Have you succeeded in getting the temperature in a simpler manner, like serial.print to the monitor?
Have you succeeded is some simple hello world test for the display?

I rather suspect it will be no to the first, because the temperature code is junk. The only line of value in it is

// The DallasTemperature library can do all this work for you!

In short, the idiots who allowed that code out the door are telling you it is junk, and you might take the hint, get the DallasTemperature library, and start over.

You might also get some sensible information from

http://www.hacktronics.com/Tutorials/arduino-1-wire-tutorial.html

note that there are two programmes to use, one to sniff the address and the other to use the sensor.