Dallas' DS1820 family temperature sensor. For more details see [https://developer.mbed.org/users/hudakz/code/DS1820/wiki/Homepage]

Dependencies:   OneWire

Dependents:   BLE_nRF24L01 frdm_serialfgmp gather_sensor_data UltiSaverController ... more

Some programs using the DS1820 library:

Import programDS1820_Hello

Simple DS1820 sensor demo showing how to use the DS1820 library [https://developer.mbed.org/users/hudakz/code/DS1820/]

Import programBLE_nRF24L01

Bluetooth Low Energy (BLE) beacon with nRF24L01(+). Data is received and displayed by Android device (Android app source code is attached).

Examples of use:

Single DS1820 sensor

/*
 * Single DS1820 sensor GPIO driven
 *
 * Note: Don't forget to connect a 4.7k Ohm resistor 
 *       between the DS1820's data pin and the +3.3V pin
 *
 *           ----------------
 *          |                |   ----------------------->  +3.3V
 *          |   MBED BOARD   |  |
 *          |                |  |   ------
 *          |          +3.3V |--o--| 4.7k |-------
 *          |                |      ------        |
 *          |                |                    |
 *          |                |                    |
 *          |                |                    |
 *          |                |                    |
 *          |           GPIO |--------------------o----->  1-wire bus/line
 *          |                |
 *          |                |
 *          |            GND |-------------------------->  GND
 *          |                |
 *           ----------------
 *
 */
 
#include "mbed.h"
#include "DS1820.h"
 
Serial serial(USBTX, USBRX);
 
int main() {
    DS1820  ds1820(D8);    // substitute D8 with actual mbed pin name connected to the DS1820 data pin    
                             
    if(ds1820.begin()) {
        while(1) {
            ds1820.startConversion();     // start temperature conversion
            ThisThread::sleep_for(1000);  // let DS1820 complete the temperature conversion
            serial.printf("temp = %3.1f\r\n", ds1820.read());     // read temperature
        }
    } else
        serial.printf("No DS1820 sensor found!\r\n");
}
 

Single DS1820 sensor. Data integrity is assured by performing CRC.

/*
 * Single DS1820 sensor GPIO driven + performing CRC
 *
 * Note: Don't forget to connect a 4.7k Ohm resistor 
 *       between the DS1820's data pin and the +3.3V pin
 *
 *           ----------------
 *          |                |   ----------------------->  +3.3V
 *          |   MBED BOARD   |  |
 *          |                |  |   ------
 *          |          +3.3V |--o--| 4.7k |-------
 *          |                |      ------        |
 *          |                |                    |
 *          |                |                    |
 *          |                |                    |
 *          |                |                    |
 *          |           GPIO |--------------------o----->  1-wire bus/line
 *          |                |
 *          |                |
 *          |            GND |-------------------------->  GND
 *          |                |
 *           ----------------
 *
 */
 
#include "mbed.h"
#include "DS1820.h"
 
Serial serial(USBTX, USBRX);
 
int main() {
    DS1820  ds1820(D8);    // substitute D8 with actual mbed pin name connected to the DS1820 data pin   
    float   temp = 0;
    int     error = 0; 
                             
    if(ds1820.begin()) {
        while(1) {
            ds1820.startConversion();    // start temperature conversion
            ThisThread::sleep_for(1000); // let DS1820 complete the temperature conversion
            error = ds1820.read(temp);   // read temperature from DS1820 and perform cyclic redundancy check (CRC)
            switch(error) {
            case 0:    // no errors -> 'temp' contains the value of measured temperature
                serial.printf("temp = %3.1f\r\n", temp);
                break;
            case 1:    // no sensor present -> 'temp' is not updated
                serial.printf("no sensor present\n\r");
                break;
            case 2:    // CRC error -> 'temp' is not updated
                serial.printf("CRC error\r\n");
            } 
        }
    } else
        serial.printf("No DS1820 sensor found!\r\n");
}
 

Several DS1820 sensors connected to the same 1-wire bus.

/*
 * Multiple sensors GPIO driven
 *
 * Note: Don't forget to connect a 4.7k Ohm resistor 
 *       between the 1-wire bus data line and the +3.3V rail
 *
 *           ----------------
 *          |                |   ----------------------->  +3.3V
 *          |   MBED BOARD   |  |
 *          |                |  |   ------
 *          |          +3.3V |--o--| 4.7k |-------
 *          |                |      ------        |
 *          |                |                    |
 *          |                |                    |
 *          |                |                    |
 *          |                |                    |
 *          |           GPIO |--------------------o----->  1-wire bus/line
 *          |                |
 *          |                |
 *          |            GND |-------------------------->  GND
 *          |                |
 *           ----------------
 *
 */

#include "mbed.h"
#include "DS1820.h"

#define     MAX_SENSOSRS   32   // max number of DS1820 sensors to be connected to the 1-wire bus (max 256)

DS1820*     ds1820[MAX_SENSOSRS];
Serial      pc(USBTX, USBRX);
DigitalOut  led(LED1);
OneWire     oneWire(D8);        // substitute D8 with the actual pin name connected to the 1-wire bus
int         sensorsFound = 0;   // counts the actually found DS1820 sensors

int main()
{
    pc.printf("\r\n--Starting--\r\n");
    
    //Enumerate (i.e. detect) DS1820 sensors on the 1-wire bus
    for (sensorsFound = 0; sensorsFound < MAX_SENSOSRS; sensorsFound++) {
        ds1820[sensorsFound] = new DS1820(&oneWire);
        if (!ds1820[sensorsFound]->begin()) {
            delete ds1820[sensorsFound];
            break;
        }
    }

    switch (sensorsFound) {
        case 0:
            pc.printf("No DS1820 sensor found!\r\n");
            return -1;

        case 1:
            pc.printf("One DS1820 sensor found.\r\n");
            break;

        default:
            pc.printf("Found %d DS1820 sensors.\r\n", sensorsFound);
    }

    while (1) {
        pc.printf("----------------\r\n");
        for (int i = 0; i < sensorsFound; i++)
            ds1820[i]->startConversion();        // start temperature conversion from analog to digital
        ThisThread::sleep_for(1000);             // let DS1820 sensors complete the temperature conversion
        for (int i = 0; i < sensorsFound; i++) {
            if (ds1820[i]->isPresent())
                pc.printf("temp[%d] = %3.1f%cC\r\n", i, ds1820[i]->read(), 176); // read temperature
        }
    }
}


Several DS1820 sensors connected to the same 1-wire bus. UART is used to implement the bus

/*
 * Multiple sensors UART driven:
 * 
 *          UART is driving the 1-Wire Bus Master according to Maxim Integrated application note
 *
 *          https://www.maximintegrated.com/en/design/technical-documents/tutorials/2/214.html
 *
 *          In addition to the 4.7k Ohm resistor between the 1-wire data bus/line and the +3.3V pin,
 *          a 470 Ohm resistor shall be tied to the UART's tx and rx pin. UART's rx pin is then used
 *          as 1-wire data bus/line.
 *
 *           ----------------
 *          |                |   ----------------------->  +3.3V
 *          |   MBED BOARD   |  |
 *          |                |  |   ------
 *          |          +3.3V |--o--| 4.7k |-------
 *          |                |      ------        |
 *          |                |      ------        |
 *          |        UART TX |-----|  470 |---    |
 *          |                |      ------    |   |
 *          |                |                |   |
 *          |        UART RX |----------------o---o----->  1-wire bus/line
 *          |                |
 *          |                |
 *          |            GND |-------------------------->  GND
 *          |                |
 *           ----------------
 *
 */
#include "mbed.h"
#include "DS1820.h"

#define MAX_SENSOSRS    32      // max number of DS1820 sensors to be connected to the 1-wire bus (max 256)
DS1820*     ds1820[MAX_SENSOSRS];
DigitalOut  led(LED1);
OneWire     oneWire(p9, p10);       // LPC1768 (UART Tx pin, UART Rx pin)
//OneWire     oneWire(PA_0, PA_1);    // NUCLE0-F446RE (UART Tx pin, UART Rx pin)
int         sensorsFound = 0;       // counts the actually found DS1820 sensors

/**
 * @brief
 * @note
 * @param
 * @retval
 */
int main()
{
    printf("\r\n--Starting--\r\n");

    //Enumerate (i.e. detect) DS1820 sensors on the 1-wire bus
    for (sensorsFound = 0; sensorsFound < MAX_SENSOSRS; sensorsFound++) {
        ds1820[sensorsFound] = new DS1820(&oneWire);
        if (!ds1820[sensorsFound]->begin()) {
            delete ds1820[sensorsFound];
            break;
        }
    }

    switch (sensorsFound) {
        case 0:
            printf("No DS1820 sensor found!\r\n");
            return -1;

        case 1:
            printf("One DS1820 sensor found.\r\n");
            break;

        default:
            printf("Found %d DS1820 sensors.\r\n", sensorsFound);
    }

    while (1) {
        led = !led;

        printf("----------------\r\n");
        for (int i = 0; i < sensorsFound; i++)
            ds1820[i]->startConversion();   // start temperature conversion from analog to digital
        #if (MBED_MAJOR_VERSION > 5)
            ThisThread::sleep_for(1s);
        #else
            wait(1);
        #endif


        for (int i = 0; i < sensorsFound; i++) {
            if (ds1820[i]->isPresent())
                printf("temp[%d] = %3.1f%cC\r\n", i, ds1820[i]->read(), 176);   // read temperature
        }
    }
}
Revision:
17:9ff584b9809f
Parent:
14:b02fa18b294a
Child:
20:98c261bcb399
--- a/DS1820.cpp	Mon Jan 21 11:38:42 2019 +0000
+++ b/DS1820.cpp	Sat Jan 26 21:22:07 2019 +0000
@@ -16,12 +16,12 @@
  *        ds1820.startConversion();
  *        wait(1.0);
  *        while(1) {
- *            serial.printf("temp = %3.1f\r\n", ds1820.read());     // read temperature
+ *            printf("temp = %3.1f\r\n", ds1820.read());     // read temperature
  *            ds1820.startConversion();     // start temperature conversion
  *            wait(1.0);                    // let DS1820 complete the temperature conversion
  *        }
  *    } else
- *        serial.printf("No DS1820 sensor found!\r\n");
+ *        printf("No DS1820 sensor found!\r\n");
  * }
  *
  * 
@@ -32,11 +32,7 @@
  
 #include "DS1820.h"
 
-#define DEBUG 0
-
-#if DEBUG
-extern Serial serial;
-#endif
+//#define DEBUG 1
 
 /**
  * @brief   Constructs a generic DS1820 sensor
@@ -83,7 +79,7 @@
     wait_ms(250);
     if(!oneWire.search(addr)) {
 #if DEBUG
-        serial.printf("No addresses.\r\n");
+        printf("No addresses.\r\n");
 #endif
         oneWire.reset_search();
         wait_ms(250);
@@ -91,11 +87,11 @@
     }
 
 #if DEBUG
-    serial.printf("ROM =");
+    printf("ROM =");
     for(uint8_t i = 0; i < 8; i++) {
-        serial.printf(" %x", addr[i]);
+        printf(" %x", addr[i]);
     }
-    serial.printf("\r\n");
+    printf("\r\n");
 #endif
 
     if(OneWire::crc8(addr, 7) == addr[7]) {
@@ -106,28 +102,28 @@
         case 0x10:
             model_s = true;
 #if DEBUG
-            serial.printf("DS18S20 or old DS1820\r\n");
+            printf("DS18S20 or old DS1820\r\n");
 #endif            
             break;
 
         case 0x28:
             model_s = false;
 #if DEBUG
-            serial.printf("DS18B20\r\n");
+            printf("DS18B20\r\n");
 #endif            
             break;
 
         case 0x22:
             model_s = false;
 #if DEBUG
-            serial.printf("DS1822\r\n");
+            printf("DS1822\r\n");
 #endif            
             break;
 
         default:
             present = false;
 #if DEBUG
-            serial.printf("Device doesn't belong to the DS1820 family\r\n");
+            printf("Device doesn't belong to the DS1820 family\r\n");
 #endif            
             return false;
         }
@@ -135,7 +131,7 @@
     }
     else {
 #if DEBUG    
-        serial.printf("Invalid CRC!\r\n");
+        printf("Invalid CRC!\r\n");
 #endif    
         return false;
     }
@@ -174,16 +170,16 @@
        
     oneWire.reset();
     oneWire.skip();
-    oneWire.write(0xBE);            // to read Scratchpad
+    oneWire.write_byte(0xBE);            // to read Scratchpad
     for(uint8_t i = 0; i < 9; i++)  // read Scratchpad bytes
-        data[i] = oneWire.read();   
+        data[i] = oneWire.read_byte();   
 
     data[4] |= (res - 9) << 5;      // update configuration byte (set resolution)  
     oneWire.reset();
     oneWire.skip();
-    oneWire.write(0x4E);            // to write into Scratchpad
+    oneWire.write_byte(0x4E);            // to write into Scratchpad
     for(uint8_t i = 2; i < 5; i++)  // write three bytes (2nd, 3rd, 4th) into Scratchpad
-        oneWire.write(data[i]);
+        oneWire.write_byte(data[i]);
 }
 
 /**
@@ -200,7 +196,7 @@
     if(present) {
         oneWire.reset();
         oneWire.skip();
-        oneWire.write(0x44);    //start temperature conversion
+        oneWire.write_byte(0x44);    //start temperature conversion
     }
 }
 
@@ -214,15 +210,15 @@
     if(present) {
         oneWire.reset();
         oneWire.skip();
-        oneWire.write(0xBE);            // to read Scratchpad
-        for(uint8_t i = 0; i < 9; i++)  // read Scratchpad bytes
-            data[i] = oneWire.read();   
+        oneWire.write_byte(0xBE);           // to read Scratchpad
+        for(uint8_t i = 0; i < 9; i++)      // reading scratchpad registers
+            data[i] = oneWire.read_byte();
 
         // Convert the raw bytes to a 16-bit unsigned value
         uint16_t*   p_word = reinterpret_cast < uint16_t * > (&data[0]);
 
 #if DEBUG
-        serial.printf("raw = %#x\r\n", *p_word);
+        printf("raw = %#x\r\n", *p_word);
 #endif            
 
         if(model_s) {
@@ -276,18 +272,24 @@
     if(present) {
         oneWire.reset();
         oneWire.skip();
-        oneWire.write(0xBE);            // to read Scratchpad
-        for(uint8_t i = 0; i < 9; i++)  // reading scratchpad registers
-            data[i] = oneWire.read();
+        oneWire.write_byte(0xBE);               // to read Scratchpad
+        for(uint8_t i = 0; i < 9; i++)          // reading scratchpad registers
+            data[i] = oneWire.read_byte();
 
         if(oneWire.crc8(data, 8) != data[8])    // if calculated CRC does not match the stored one
+        {
+#if DEBUG
+            for(uint8_t i = 0; i < 9; i++)
+                printf("data[%d]=0x%.2x\r\n", i, data[i]);
+#endif            
             return 2;                           // return with CRC error
+        }
 
         // Convert the raw bytes to a 16bit unsigned value
         uint16_t*   p_word = reinterpret_cast < uint16_t * > (&data[0]);
 
 #if DEBUG
-        serial.printf("raw = %#x\r\n", *p_word);
+        printf("raw = %#x\r\n", *p_word);
 #endif
 
         if(model_s) {
@@ -348,4 +350,3 @@
         return (float(word) / 256.0f);
 }
 
-