Diff: DS1820.cpp

Revision:

20:98c261bcb399

Parent:

17:9ff584b9809f

Child:

22:16537aa25bd9

--- a/DS1820.cpp	Sun Jan 27 18:02:01 2019 +0000
+++ b/DS1820.cpp	Sun Mar 10 13:19:03 2019 +0000
@@ -5,34 +5,114 @@
  *
  * Example of use:
  * 
- * #include "DS1820.h"
+ * Single sensor.
  *
- * Serial serial(USBTX, USBRX);
+ * #include "mbed.h"
+ * #include "DS1820.h"
+ * 
+ * Serial      pc(USBTX, USBRX);
+ * DigitalOut  led(LED1);
+ * OneWire     oneWire(D8);    // substitute D8 with actual mbed pin name connected 1-wire bus
+ * float       temp = 0;
+ * int         result = 0;
+ * 
+ * int main()
+ * {
+ *     pc.printf("\r\n--Starting--\r\n");
+ *     if (ds1820.begin()) {
+ *         while (1) {
+ *             ds1820.startConversion();   // start temperature conversion from analog to digital
+ *             wait(1.0);                  // let DS1820 complete the temperature conversion
+ *             result = ds1820.read(temp); // read temperature from DS1820 and perform cyclic redundancy check (CRC)
+ *             switch (result) {
+ *                 case 0:                 // no errors -> 'temp' contains the value of measured temperature
+ *                     pc.printf("temp = %3.1f%cC\r\n", temp, 176);
+ *                     break;
+ * 
+ *                 case 1:                 // no sensor present -> 'temp' is not updated
+ *                     pc.printf("no sensor present\n\r");
+ *                     break;
+ * 
+ *                 case 2:                 // CRC error -> 'temp' is not updated
+ *                     pc.printf("CRC error\r\n");
+ *             }
+ * 
+ *             led = !led;
+ *         }
+ *     }
+ *     else
+ *         pc.printf("No DS1820 sensor found!\r\n");
+ * }
+ * 
+ * 
+ * More sensors connected to the same 1-wire bus.
+ * 
+ * #include "mbed.h"
+ * #include "DS1820.h"
+ * 
+ * #define     SENSORS_COUNT   64      // number of DS1820 sensors to be connected to the 1-wire bus (max 256)
+ * 
+ * Serial      pc(USBTX, USBRX);
+ * DigitalOut  led(LED1);
+ * OneWire     oneWire(D8);            // substitute D8 with actual mbed pin name connected to the DS1820 data pin
+ * DS1820*     ds1820[SENSORS_COUNT];
+ * int         sensors_found = 0;      // counts the actually found DS1820 sensors
+ * float       temp = 0;
+ * int         result = 0;
  * 
  * int main() {
- *     DS1820  ds1820(PA_9);    // substitute PA_9 with actual mbed pin name connected to the DS1820 data pin
- *
- *     if(ds1820.begin()) {
- *        ds1820.startConversion();
- *        wait(1.0);
- *        while(1) {
- *            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
- *        printf("No DS1820 sensor found!\r\n");
+ *     int i = 0;
+ *     
+ *     pc.printf("\r\n Starting \r\n");
+ *     //Enumerate (i.e. detect) DS1820 sensors on the 1-wire bus
+ *     for(i = 0; i < SENSORS_COUNT; i++) {
+ *         ds1820[i] = new DS1820(&oneWire);
+ *         if(!ds1820[i]->begin()) {
+ *             delete ds1820[i];
+ *             break;
+ *         }
+ *     }
+ *     
+ *     sensors_found = i;
+ *     
+ *     if (sensors_found == 0) {
+ *         pc.printf("No DS1820 sensor found!\r\n");
+ *         return -1;
+ *     }
+ *     else
+ *         pc.printf("Found %d sensors.\r\n", sensors_found);
+ *     
+ *     while(1) {
+ *         pc.printf("-------------------\r\n");
+ *         for(i = 0; i < sensors_found; i++)
+ *             ds1820[i]->startConversion();   // start temperature conversion from analog to digital       
+ *         wait(1.0);                          // let DS1820s complete the temperature conversion
+ *         for(int i = 0; i < sensors_found; i++) {
+ *             if(ds1820[i]->isPresent())
+ *                 pc.printf("temp[%d] = %3.1f%cC\r\n", i, ds1820[i]->read(), 176);     // read temperature
+ *         }
+ *     }
  * }
- *
  * 
- * Note: Don't forget to connect a 4.7k Ohm resistor 
- *       between the DS1820's data pin and the +3.3V pin
- *
  */
  
 #include "DS1820.h"
 
-//#define DEBUG 1
+#define DEBUG 0
+
+//* Initializing static members
+uint8_t DS1820::lastAddr[8] = {0, 0, 0, 0, 0, 0, 0, 0};
+/**
+ * @brief   Constructs a generic DS1820 sensor
+ * @note    begin() must be called to detect and initialize the actual model
+ * @param   pin: Name of data pin
+ * @retval
+ */
+DS1820::DS1820(PinName pin) {
+    oneWire = new OneWire(pin);
+    present = false;
+    model_s = false;
+}
 
 /**
  * @brief   Constructs a generic DS1820 sensor
@@ -40,34 +120,13 @@
  * @param   pin: Name of data pin
  * @retval
  */
-DS1820::DS1820(PinName pin) :
-    oneWire(pin) {
+DS1820::DS1820(OneWire* wire) :
+    oneWire(wire) {
     present = false;
     model_s = false;
 }
 
 /**
- * @brief   Constructs a specific model
- * @note    No need to call begin() to detect and initialize the model
- * @param   model:  One character model name: 'S', 's', 'B' or 'b'
- *          pin:    Name of data pin
- * @retval
- */
-DS1820::DS1820(char model, PinName pin) :
-    oneWire(pin) {
-    if((model == 'S') or (model == 's')) {
-        present = true;
-        model_s = true;
-    }
-    else if((model == 'B') or (model == 'b')) {
-        present = true;
-        model_s = false;
-    }
-    else
-        present = false;
-}
-
-/**
  * @brief   Detects and initializes the actual DS1820 model
  * @note
  * @param
@@ -75,16 +134,24 @@
             false:  otherwise
  */
 bool DS1820::begin(void) {
-    oneWire.reset_search();
-    wait_ms(250);
-    if(!oneWire.search(addr)) {
+#if DEBUG
+    printf("lastAddr =");
+    for(uint8_t i = 0; i < 8; i++) {
+        printf(" %x", lastAddr[i]);
+    }
+    printf("\r\n");
+#endif
+    if(!oneWire->search(lastAddr)) {
 #if DEBUG
         printf("No addresses.\r\n");
 #endif
-        oneWire.reset_search();
+        oneWire->reset_search();
         wait_ms(250);
         return false;
     }
+    
+    for (int i = 0; i < 8; i++)
+        addr[i] = lastAddr[i];
 
 #if DEBUG
     printf("ROM =");
@@ -168,18 +235,18 @@
     if(model_s)
         res = 9;
        
-    oneWire.reset();
-    oneWire.skip();
-    oneWire.write_byte(0xBE);            // to read Scratchpad
+    oneWire->reset();
+    oneWire->select(addr);
+    oneWire->write_byte(0xBE);            // to read Scratchpad
     for(uint8_t i = 0; i < 9; i++)  // read Scratchpad bytes
-        data[i] = oneWire.read_byte();   
+        data[i] = oneWire->read_byte();   
 
     data[4] |= (res - 9) << 5;      // update configuration byte (set resolution)  
-    oneWire.reset();
-    oneWire.skip();
-    oneWire.write_byte(0x4E);            // to write into Scratchpad
+    oneWire->reset();
+    oneWire->select(addr);
+    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_byte(data[i]);
+        oneWire->write_byte(data[i]);
 }
 
 /**
@@ -194,9 +261,9 @@
  */
 void DS1820::startConversion(void) {
     if(present) {
-        oneWire.reset();
-        oneWire.skip();
-        oneWire.write_byte(0x44);    //start temperature conversion
+        oneWire->reset();
+        oneWire->select(addr);
+        oneWire->write_byte(0x44);    //start temperature conversion
     }
 }
 
@@ -208,11 +275,11 @@
  */
 float DS1820::read(void) {
     if(present) {
-        oneWire.reset();
-        oneWire.skip();
-        oneWire.write_byte(0xBE);           // to read Scratchpad
+        oneWire->reset();
+        oneWire->select(addr);
+        oneWire->write_byte(0xBE);           // to read Scratchpad
         for(uint8_t i = 0; i < 9; i++)      // reading scratchpad registers
-            data[i] = oneWire.read_byte();
+            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]);
@@ -270,13 +337,13 @@
  */
 uint8_t DS1820::read(float& temp) {
     if(present) {
-        oneWire.reset();
-        oneWire.skip();
-        oneWire.write_byte(0xBE);               // to read Scratchpad
+        oneWire->reset();
+        oneWire->select(addr);
+        oneWire->write_byte(0xBE);               // to read Scratchpad
         for(uint8_t i = 0; i < 9; i++)          // reading scratchpad registers
-            data[i] = oneWire.read_byte();
+            data[i] = oneWire->read_byte();
 
-        if(oneWire.crc8(data, 8) != data[8])    // if calculated CRC does not match the stored one
+        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++)