Diff: MAX31850.h

Revision:

0:5530bf2d0e94

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+++ b/MAX31850.h	Wed Jan 23 23:44:57 2019 +0000
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+/* mbed MAX31850
+ Library, for the Dallas (Maxim) 1-Wire Digital Thermometer
+ * Copyright (c) 2010, Michael Hagberg Michael@RedBoxCode.com
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ * 
+ * 
+ * This library has been adapted from the DS1820 library to work with MAX31850 thermocouple sensor
+ * Chris Roberts (croberts21@my.whitworth.edu)
+ * Craig Russell (crussell21@my.whitworth.edu)
+ * 
+ * For our application, we modified readAll() (previously convertTemperature) to force a small 
+ * wait rather than it being optional, and removed the ability to select a single sensor.
+ * 
+ * getTemp() (previously temperature) has been updated to deal with the correct number of bits that 
+ * the temperature is stored in as well as updated convertions to all four units
+ * 
+ *  as well as adding a setUnits() function to set the 
+ * units that the sensor will return.
+ * 
+ * We removed some functionality that dealt with parasite power. 
+ * 
+ *
+ */
+
+#ifndef MBED_MAX31850_H
+#define MBED_MAX31850_H
+
+#include "mbed.h"
+#include "LinkedList.h"
+
+#define C 0 //celsius 
+#define K 1 //Kelvin
+#define F 2 //fahrenheit
+#define R 3 //Rankin
+
+extern Serial pc;
+
+/** MAX31850
+ *
+ * Example:
+ * @code
+ * #include "mbed.h"
+ * #include "MAX31850.h"
+ *
+ * MAX31850 probe(DATA_PIN);
+ *  
+ * int main() {
+ *     while(true) {
+ *         probe.convertTemperature(true, MAX31850::all_devices); //Start temperature conversion, wait until ready
+ *         printf("It is %3.1foC\r\n", probe.temperature());
+ *         wait(1);
+ *     }
+ * }
+ * @endcode
+ */
+class MAX31850
+ {
+public:
+    enum devices{
+        this_device,     // command applies to only this device
+        all_devices };   // command applies to all devices
+    
+    enum {
+        invalid_conversion = -1000
+    };
+
+    /** Create a probe object connected to the specified pins
+    * 
+    * The probe might either by regular powered or parasite powered. If it is parasite
+    * powered and power_pin is set, that pin will be used to switch an external mosfet connecting
+    * data to Vdd. If it is parasite powered and the pin is not set, the regular data pin
+    * is used to supply extra power when required. This will be sufficient as long as the 
+    * number of probes is limitted.
+    * 
+    * For our application, we have the functions set up to only use external power. The constructor still supports
+    * parasite power but the functions to not support it.
+    */
+    MAX31850 (PinName data_pin, PinName power_pin = NC, bool power_polarity = 0); // Constructor with parasite power pin
+  
+    ~MAX31850();
+
+    /** Function to see if there are MAX31850
+     *  devices left on a pin which do not have a corresponding MAX31850
+     *  object
+    *
+    * @return - true if there are one or more unassigned devices, otherwise false
+      */
+    static bool unassignedProbe(PinName pin);
+
+    /** This routine will initiate the temperature conversion within
+      *  all MAX31850
+      *  probes. 
+      */
+    void readAll();
+
+    /** This function will return the probe temperature. Approximately 10ms per
+      * probe to read its scratchpad, do CRC check and convert temperature on the LPC1768.
+      *
+      * @scratchpad scale, may be either 'c', 'f', 'k', and 'r'
+      * @returns temperature for that scale, or MAX31850::invalid_conversion (-1000) if CRC error detected.
+      */
+    float getTemp(int scale = 4);     
+
+    /** This function returns the 64 bit address associated with a
+      * particular DS18B20.
+      *
+      * Contributed by John M. Larkin (jlarkin@whitworth.edu)
+      *
+      * @returns unsigned long long
+      */
+    unsigned long long getId();
+
+
+    /** This function sets the _units variable to the 
+     * users desired temperature units
+     */
+    void setUnits(int);
+    
+
+private:
+    bool _parasite_power;
+    bool _power_mosfet;
+    bool _power_polarity;
+    
+    static char CRC_byte(char _CRC, char byte );
+    static bool onewire_reset(DigitalInOut *pin);
+    void match_ROM();
+    void skip_ROM();
+    static bool search_ROM_routine(DigitalInOut *pin, char command, char *ROM_address);
+    static void onewire_bit_out (DigitalInOut *pin, bool bit_data);
+    void onewire_byte_out(char data);
+    static bool onewire_bit_in(DigitalInOut *pin);
+    char onewire_byte_in();
+    static bool ROM_checksum_error(char *_ROM_address);
+    bool scratchpad_checksum_error();
+    void read_scratchpad();
+    static bool unassignedProbe(DigitalInOut *pin, char *ROM_address);
+
+    DigitalInOut _datapin;
+    DigitalOut _parasitepin;
+    
+    char _ROM[8];
+    char scratchpad[9];
+    int _units;
+    
+    static LinkedList<node> probes;
+};
+#endif
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