Diff: DS1820.h

Revision:

0:a43dcf6ca539

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DS1820.h	Tue Dec 29 13:08:05 2020 +0000
@@ -0,0 +1,120 @@
+
+#ifndef MBED_DS1820_H
+#define MBED_DS1820_H
+
+#include "mbed.h"
+#include "LinkedList2.h"
+
+#define FAMILY_CODE _ROM[0]
+#define FAMILY_CODE_DS1820 0x10
+#define FAMILY_CODE_DS18B20 0x28
+#define FAMILY_CODE_DS1822  0x22
+
+/** DS1820 Dallas 1-Wire Temperature Probe
+ *
+ * Example for single sensor:
+ * @code
+ * #include "mbed.h"
+ * #include "DS1820.h"
+ *
+ * DS1820 probe(DATA_PIN);
+ *  
+ * int main() {
+ *     while(1) {
+ *         probe.convertTemperature(true, DS1820::all_devices); //Start temperature conversion, wait until completed
+ *         printf("It is %3.1foC\r\n", probe.temperature());
+ *         ThisThread::sleep_for(chrono::milliseconds(1000));
+ *     }
+ * }
+ * @endcode
+ */
+class DS1820 {
+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.
+     *
+     * @param data_pin DigitalInOut pin for the data bus
+     * @param power_pin DigitalOut (optional) pin to control the power MOSFET
+     * @param power_polarity bool (optional) which sets active state (0 for active low (default), 1 for active high)
+     */
+    DS1820(PinName data_pin, PinName power_pin = NC, bool power_polarity = 0); // Constructor with parasite power pin
+    ~DS1820();
+
+    /** Function to see if there are DS1820 devices left on a pin which do not have a corresponding DS1820 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
+      * one or all DS1820 probes. 
+      *
+      * @param wait if true or parisitic power is used, waits up to 750 ms for 
+      * conversion otherwise returns immediatly.
+      * @param device allows the function to apply to a specific device or
+      * to all devices on the 1-Wire bus.
+      * @returns milliseconds untill conversion will complete.
+      */
+    int convertTemperature(bool wait, devices device=all_devices);
+
+    /** This function will return the probe temperature. Approximately 10ms per
+      * probe to read its RAM, do CRC check and convert temperature on the LPC1768.
+      *
+      * @param scale, may be either 'c' or 'f'
+      * @returns temperature for that scale, or DS1820::invalid_conversion (-1000) if CRC error detected.
+      */
+    float temperature(char scale='c');
+
+    /** This function sets the temperature resolution for the DS18B20
+      * in the configuration register.
+      *
+      * @param a number between 9 and 12 to specify resolution
+      * @returns true if successful
+      */ 
+    bool setResolution(unsigned int resolution);  
+    
+    static LinkedList2<node> probes;     
+
+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 RAM_checksum_error();
+    void read_RAM();
+    static bool unassignedProbe(DigitalInOut *pin, char *ROM_address);
+    void write_scratchpad(int data);
+    bool read_power_supply(devices device=this_device);
+
+    DigitalInOut _datapin;
+    DigitalOut _parasitepin;
+    
+    char _ROM[8];
+    char RAM[9];
+};
+
+
+#endif
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