DS18B20.hpp

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00032 
00033 #ifndef MaximInterfaceDevices_DS18B20_hpp
00034 #define MaximInterfaceDevices_DS18B20_hpp
00035 
00036 #include <MaximInterfaceCore/array.hpp>
00037 #include <MaximInterfaceCore/SelectRom.hpp>
00038 #include <MaximInterfaceCore/Sleep.hpp>
00039 #include "Config.hpp"
00040 
00041 namespace MaximInterfaceDevices {
00042 
00043 /// @brief DS18B20 Programmable Resolution 1-Wire Digital Thermometer
00044 /// @details The DS18B20 digital thermometer provides 9-bit to 12-bit
00045 /// Celsius temperature measurements and has an alarm function with
00046 /// nonvolatile user-programmable upper and lower trigger points. The
00047 /// DS18B20 communicates over a 1-Wire bus that by definition requires
00048 /// only one data line (and ground) for communication with a central
00049 /// microprocessor. In addition, the DS18B20 can derive power directly
00050 /// from the data line ("parasite power"), eliminating the need for an
00051 /// external power supply.
00052 class DS18B20 {
00053 public:
00054   enum ErrorValue { CrcError = 1, DataError };
00055 
00056   static const uint_least8_t nineBitResolution = 0x1F;
00057   static const uint_least8_t tenBitResolution = 0x3F;
00058   static const uint_least8_t elevenBitResolution = 0x5F;
00059   static const uint_least8_t twelveBitResolution = 0x7F;
00060 
00061   /// Holds the contents of the device scratchpad.
00062   typedef Core::array<uint_least8_t, 8> Scratchpad;
00063 
00064   DS18B20(Core::Sleep & sleep, Core::OneWireMaster & master,
00065           const Core::SelectRom & selectRom)
00066       : selectRom(selectRom), master(&master), sleep(&sleep), resolution(0) {}
00067 
00068   void setSleep(Core::Sleep & sleep) { this->sleep = &sleep; }
00069 
00070   void setMaster(Core::OneWireMaster & master) { this->master = &master; }
00071 
00072   void setSelectRom(const Core::SelectRom & selectRom) {
00073     this->selectRom = selectRom;
00074   }
00075 
00076   /// Initializes the device for first time use.
00077   MaximInterfaceDevices_EXPORT Core::Result<void> initialize() const;
00078 
00079   /// @brief Write Scratchpad Command
00080   /// @details If the result of a temperature measurement is higher
00081   /// than TH or lower than TL, an alarm flag inside the device is
00082   /// set. This flag is updated with every temperature measurement.
00083   /// As long as the alarm flag is set, the DS1920 will respond to
00084   /// the alarm search command.
00085   /// @param[in] th 8-bit upper temperature threshold, MSB indicates sign.
00086   /// @param[in] tl 8-bit lower temperature threshold, LSB indicates sign.
00087   /// @param[in] res Resolution of the DS18B20.
00088   MaximInterfaceDevices_EXPORT Core::Result<void>
00089   writeScratchpad(uint_least8_t th, uint_least8_t tl, uint_least8_t res);
00090 
00091   /// @brief Read Scratchpad Command
00092   /// @returns scratchpad Contents of scratchpad.
00093   MaximInterfaceDevices_EXPORT Core::Result<Scratchpad> readScratchpad() const;
00094 
00095   /// @brief Copy Scratchpad Command
00096   /// @details This command copies from the scratchpad into the
00097   /// EEPROM of the DS18B20, storing the temperature trigger bytes
00098   /// and resolution in nonvolatile memory.
00099   MaximInterfaceDevices_EXPORT Core::Result<void> copyScratchpad();
00100 
00101   /// @brief Read Power Supply command
00102   /// @details This command determines if the DS18B20 is parasite
00103   /// powered or has a local supply
00104   /// @returns
00105   /// True if the device is powered by a local power supply, or false if the
00106   /// device is parasitically powered.
00107   MaximInterfaceDevices_EXPORT Core::Result<bool> readPowerSupply() const;
00108 
00109   /// @brief Convert Temperature Command
00110   /// @details This command begins a temperature conversion.
00111   MaximInterfaceDevices_EXPORT Core::Result<void> convertTemperature();
00112 
00113   /// @brief Recall Command
00114   /// @details This command recalls the temperature trigger values
00115   /// and resolution stored in EEPROM to the scratchpad.
00116   MaximInterfaceDevices_EXPORT Core::Result<void> recallEeprom();
00117 
00118   MaximInterfaceDevices_EXPORT static const Core::error_category &
00119   errorCategory();
00120 
00121 private:
00122   Core::SelectRom selectRom;
00123   Core::OneWireMaster * master;
00124   const Core::Sleep * sleep;
00125   mutable uint_least8_t resolution;
00126 };
00127 
00128 /// @brief Reads the current temperature as an integer value with decimal.
00129 /// @param ds18b20 Device to read.
00130 /// @returns Temperature in degrees Celsius multiplied by 16.
00131 MaximInterfaceDevices_EXPORT Core::Result<int>
00132 readTemperature(DS18B20 & ds18b20);
00133 
00134 } // namespace MaximInterfaceDevices
00135 namespace MaximInterfaceCore {
00136 
00137 template <>
00138 struct is_error_code_enum<MaximInterfaceDevices::DS18B20::ErrorValue>
00139     : true_type {};
00140 
00141 } // namespace MaximInterfaceCore
00142 namespace MaximInterfaceDevices {
00143 
00144 inline Core::error_code make_error_code(DS18B20::ErrorValue e) {
00145   return Core::error_code(e, DS18B20::errorCategory());
00146 }
00147 
00148 } // namespace MaximInterfaceDevices
00149 
00150 #endif