Bob Giesberts
Direct copy of the library, but apparently I made a change?
Fork of
SHTx
by 
Roy van Dam
Diff: sht15.hpp
- Revision:
- 0:d55659b0c4a0
- Child:
- 1:8465801be23f
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/sht15.hpp Thu Nov 18 10:23:43 2010 +0000
@@ -0,0 +1,249 @@
+/**
+ * Copyright (c) 2010 Roy van Dam <roy@negative-black.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef _SHT15_HPP_
+#define _SHT15_HPP_
+
+#include "mbed.h"
+#include "i2c.hpp"
+
+namespace SHTx {
+ /**
+ * Class: SHT15
+ * Humidity and Temperature Sensor - SHT15
+ * High level software interface.
+ */
+ class SHT15 {
+ private:
+ I2C i2c;
+
+ bool ready;
+ bool scale;
+
+ uint8_t status_register;
+ uint16_t humidity;
+ uint16_t temperature;
+
+ struct coefficients {
+ // Humidity conversion coefficients
+ float c1[2], c2[2], c3[2];
+
+ // Temperature conversion coefficients
+ float dc[2], df[2], dv[2];
+
+ // Temperature compensation coefficients
+ float t1[2], t2[2];
+
+ // Initialize table
+ coefficients(void) {
+ c1[0] = -2.046f; c2[1] = -2.046f;
+ c2[0] = 0.036f; c2[1] = 0.587f;
+ c3[0] = -0.0000015955f; c2[1] = -0.00040845f;
+
+ dc[0] = 0.01f; dc[1] = 0.04f;
+ df[0] = 0.018f; df[1] = 0.072f;
+ dv[0] = -39.7f; dv[1] = -39.5f;
+
+ t1[0] = 0.01f; t1[1] = 0.01f;
+ t2[0] = 0.00008f; t2[1] = 0.00128f;
+ };
+ } coefficient;
+
+ enum cmd_list {
+ cmd_read_temperature = 0x03,
+ cmd_read_humidity = 0x05,
+ cmd_read_register = 0x07,
+ cmd_write_register = 0x06,
+ cmd_reset_device = 0x1E
+ };
+
+ enum flag_list {
+ flag_resolution = 0x01,
+ flag_reset = 0x02,
+ flag_heater = 0x04,
+ flag_battery = 0x40
+ };
+
+ public:
+ /*
+ * Initializes I2C interface and waits
+ * the 11ms device initialization time.
+ */
+ SHT15(PinName sda, PinName scl);
+
+ /**
+ * Function: getTemperature
+ * Returns the current temperature.
+ *
+ * Values:
+ * returns - current temperature.
+ */
+ float getTemperature(void);
+
+ /**
+ * Function: getHumidity
+ * Returns the current relative humidity.
+ *
+ * Values:
+ * returns - relative humidity.
+ */
+ float getHumidity(void);
+
+ /**
+ * Function: checkBattery
+ * Returns true if battery voltage drops
+ * below 2.4 volt.
+ *
+ * Values:
+ * returns - true on low battery, false otherwise
+ */
+ bool checkBattery(void);
+
+ /**
+ * Function: setHeater
+ * Enable on chip heating element. The heater may
+ * increase the temperature of the sensor by 5C to
+ * 10C beyond ambient temperature.
+ *
+ * Values:
+ * value - true->on, false->off
+ * return - operation result
+ */
+ bool setHeater(bool value);
+
+ /**
+ * Function: setResolution
+ * Set lower measurement resolution to allow
+ * faster update frequencies.
+ *
+ * Resolutions
+ * low: 8bit humid. - 12bit temp.
+ * high: 12bit humid. - 14bit temp.
+ *
+ * Values:
+ * value - true->low, false->high
+ * return - operation result
+ */
+ bool setResolution(bool value);
+
+ /**
+ * Function: setScale
+ * Sets output scale to fahrenheit or celcius.
+ *
+ * Values:
+ * value - true->fahrenheit, false->celcius
+ */
+ void setScale(bool value);
+
+ /**
+ * Function: update
+ * Performs humidity and temperature
+ * sensor readout of the chip.
+ *
+ * Values:
+ * return - operation result
+ */
+ bool update(void);
+
+ /**
+ * Function: reset
+ * Performs full chip reset.
+ *
+ * Values:
+ * return - operation result
+ */
+ bool reset(void);
+
+ private:
+
+ /**
+ * Function: convertTemperature
+ * Convert sensor data to human readable value
+ * on the farenheit or celcius scale.
+ *
+ * Values:
+ * sot - raw temperatue sensor output
+ * res - true->low, false->high
+ * scale - true->fahrenheit, false->celcius
+ * return - temperature
+ */
+ float convertTemperature(uint16_t sot, bool res = false, bool scale = false);
+
+ /**
+ * Function: convertHumidity
+ * Convert sensor data to relative humidity
+ * in percentage.
+ *
+ * Values:
+ * sohr - raw humidity sensor output
+ * sot - raw temperatue sensor output
+ * res - true->low, false->high
+ * return - relative humidity
+ */
+ float convertHumidity(uint16_t sohr, uint16_t sot, bool res = false);
+
+ /**
+ * Function: writeRegister
+ * Write internal chip register.
+ *
+ * Values:
+ * return - operation result
+ */
+ bool writeRegister(void);
+
+ /**
+ * Function: readRegister
+ * Reads internal chip register
+ *
+ * Values:
+ * command - register to be accessed
+ * return - operation result
+ */
+ bool readRegister(cmd_list command);
+
+ /**
+ * Function: setFlag
+ * Modify local register flag.
+ *
+ * Values:
+ * flag - flag to be modified
+ * value - value to be assigned
+ */
+ void setFlag(flag_list flag, bool value);
+
+ /**
+ * Function: getFlag
+ * Get local register flag.
+ *
+ * Values:
+ * returns - flag value
+ */
+ bool getFlag(flag_list flag);
+ };
+}
+
+/* !_SHT15_HPP_ */
+#endif
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