DS1920.hpp

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00032 
00033 #ifndef MaximInterfaceDevices_DS1920_hpp
00034 #define MaximInterfaceDevices_DS1920_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 DS1920 1-Wire Temperature iButton
00044 /// @details The iButton® temperature logger (DS1920) provides
00045 /// direct-to-digital 9-bit temperature readings over a range of
00046 /// -55°C to +100°C in 0.5° increments. The iButton communicates with
00047 /// a processor using the 1-Wire® protocol through a hardware port
00048 /// interface. The port interface provides both the physical link and
00049 /// handles the communication protocols that enable the processor to
00050 /// access iButton resources with simple commands. Two bytes of
00051 /// EEPROM can be used either to set alarm triggers or for storing
00052 /// user data.
00053 class DS1920 {
00054 public:
00055   enum ErrorValue { CrcError = 1, DataError };
00056 
00057   /// Holds the contents of the device scratchpad.
00058   typedef Core::array<uint_least8_t, 8> Scratchpad;
00059 
00060   DS1920(Core::Sleep & sleep, Core::OneWireMaster & master,
00061          const Core::SelectRom & selectRom)
00062       : selectRom(selectRom), master(&master), sleep(&sleep) {}
00063 
00064   void setSleep(Core::Sleep & sleep) { this->sleep = &sleep; }
00065 
00066   void setMaster(Core::OneWireMaster & master) { this->master = &master; }
00067 
00068   void setSelectRom(const Core::SelectRom & selectRom) {
00069     this->selectRom = selectRom;
00070   }
00071 
00072   /// @brief Write Scratchpad Command
00073   /// @details If the result of a temperature measurement is higher
00074   /// than TH or lower than TL, an alarm flag inside the device is
00075   /// set. This flag is updated with every temperature measurement.
00076   /// As long as the alarm flag is set, the DS1920 will respond to
00077   /// the alarm search command.
00078   /// @param[in] th 8-bit upper temperature threshold, MSB indicates sign.
00079   /// @param[in] tl 8-bit lower temperature threshold, MSB indicates sign.
00080   MaximInterfaceDevices_EXPORT Core::Result<void>
00081   writeScratchpad(uint_least8_t th, uint_least8_t tl);
00082 
00083   /// @brief Read Scratchpad Command
00084   /// @returns Contents of scratchpad.
00085   MaximInterfaceDevices_EXPORT Core::Result<Scratchpad> readScratchpad() const;
00086 
00087   /// @brief Copy Scratchpad Command
00088   /// @details This command copies from the scratchpad into the
00089   /// EEPROM of the DS1920, storing the temperature trigger bytes
00090   /// in nonvolatile memory.
00091   MaximInterfaceDevices_EXPORT Core::Result<void> copyScratchpad();
00092 
00093   /// @brief Convert Temperature Command
00094   /// @details This command begins a temperature conversion.
00095   MaximInterfaceDevices_EXPORT Core::Result<void> convertTemperature();
00096 
00097   /// @brief Recall Command
00098   /// @details This command recalls the temperature trigger values
00099   /// stored in EEPROM to the scratchpad.
00100   MaximInterfaceDevices_EXPORT Core::Result<void> recallEeprom();
00101 
00102   MaximInterfaceDevices_EXPORT static const Core::error_category &
00103   errorCategory();
00104 
00105 private:
00106   Core::SelectRom selectRom;
00107   Core::OneWireMaster * master;
00108   const Core::Sleep * sleep;
00109 };
00110 
00111 /// @brief Reads the current temperature as an integer value.
00112 /// @param ds1920 Device to read.
00113 /// @returns Temperature in degrees Celsius multiplied by 2.
00114 MaximInterfaceDevices_EXPORT Core::Result<int> readTemperature(DS1920 & ds1920);
00115 
00116 } // namespace MaximInterfaceDevices
00117 namespace MaximInterfaceCore {
00118 
00119 template <>
00120 struct is_error_code_enum<MaximInterfaceDevices::DS1920::ErrorValue>
00121     : true_type {};
00122 
00123 } // namespace MaximInterfaceCore
00124 namespace MaximInterfaceDevices {
00125 
00126 inline Core::error_code make_error_code(DS1920::ErrorValue e) {
00127   return Core::error_code(e, DS1920::errorCategory());
00128 }
00129 
00130 } // namespace MaximInterfaceDevices
00131 
00132 #endif