Si7020 Device Driver

Diff: Si7020.h

Revision:

0:9a1febb56203

diff -r 000000000000 -r 9a1febb56203 Si7020.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Si7020.h	Fri Apr 17 09:53:45 2015 -0500
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+/*******************************************************************************
+ * Copyright (C) 2015 Maxim Integrated Products, Inc., All Rights Reserved.
+ *
+ * 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 MAXIM INTEGRATED 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.
+ *
+ * Except as contained in this notice, the name of Maxim Integrated
+ * Products, Inc. shall not be used except as stated in the Maxim Integrated
+ * Products, Inc. Branding Policy.
+ *
+ * The mere transfer of this software does not imply any licenses
+ * of trade secrets, proprietary technology, copyrights, patents,
+ * trademarks, maskwork rights, or any other form of intellectual
+ * property whatsoever. Maxim Integrated Products, Inc. retains all
+ * ownership rights.
+ *******************************************************************************
+ */
+
+#ifndef _SI7020_H_
+#define _SI7020_H_
+
+#include "mbed.h"
+
+/**
+ * Silicon Labs Si7020 Humidity and Temperature Sensor
+ *
+ * @code
+ * #include <stdio.h>
+ * #include "mbed.h"
+ * #include "Si7020.h"
+ * 
+ * I2C i2c(I2C_SDA, I2C_SCL);
+ * Si7020 si(&i2c);
+ * 
+ * int main()
+ * {
+ *     while(1) {
+ * 
+ *         float humid;
+ *         if(si.getHumidity(&humid) != 0) {
+ *             printf("Error getting humidity\n");
+ *             humid = -1;
+ *         }
+ * 
+ *         float temp;
+ *         if(si.getTemperature(&temp) != 0) {
+ *             printf("Error getting temperature");
+ *             temp = -1;
+ *         } 
+ *         printf("Humidity = %f%% Temperature = %fC\n", humid, temp);
+ * 
+ *         wait(1);
+ *     }
+ * }
+ * @endcode
+ */
+class Si7020
+{
+
+public:
+
+    /**
+     * @brief   Measurement resolution.
+     * @details Controls the resolution of the humidity and temperarure readings.
+     */
+    typedef enum {
+        RH_12b_TEMP_14b = 0x0, ///< 12 bits for RH, 14 bits for Temp
+        RH_8b_TEMP_12b = 0x1,  ///< 8 bits for RH, 12 bits for Temp
+        RH_10b_TEMP_13b = 0x2, ///< 10 bits for RH, 13 bits for Temp
+        RH_11b_TEMP_11b = 0x3, ///< 11 bits for RH, 11 bits for Temp
+    } resolution_t;
+
+    /**
+     * Si7020 constructor.
+     *
+     * @param sda mbed pin to use for SDA line of I2C interface.
+     * @param scl mbed pin to use for SCL line of I2C interface.
+     */
+    Si7020(PinName sda, PinName scl);
+
+    /**
+     * Si7020 constructor.
+     *
+     * @param i2c I2C object to use
+     */
+    Si7020(I2C *i2c);
+
+    /**
+     * Si7020 destructor.
+     */
+    ~Si7020();
+
+    /**
+     * @brief   Reset.
+     * @details Sends the rest command.
+     * @returns 0 if no errors, -1 if error.
+     */
+    int reset(void);
+
+    /**
+     * @brief   Get Electronic ID.
+     * @details Gets the Electronic ID of the connected device. Verifies the 
+     *          ID with an 8-bit CRC.
+     *
+     * @param   Character buffer to store the id. Needs to be at least 8 bytes.
+     * @returns 0 if no errors, -1 if error.
+     */
+    int getElectronicId(char *id);
+
+    /**
+     * @brief   Configure sample resolution.
+     * @details Sets the number of bits used for humidity and temperature readings.
+     * @param   resolution Enum for the resolution setting.
+     * @returns 0 if no errors, -1 if error.
+     */
+    int configResolution(Si7020::resolution_t resolution);
+
+    /**
+     * @brief   Get temperature reading.
+     * @details Initiates a temperature reading and blocks until reading has
+     *          been calculated. 
+     * 
+     * @note    Will hold the I2C bus until reading is complete. Refer to datasheet
+     *          for timing specifications.
+     * 
+     * @param   tempCx10 Pointer for temperature reading. Unit is 1/10th degree Celcius.
+     * @returns 0 if no errors, -1 if error.
+     */
+    int getTemperature(int16_t *tempCx10);
+
+    /**
+     * @brief   Get temperature reading.
+     * @details Initiates a temperature reading and blocks until reading has
+     *          been calculated. 
+     * 
+     * @note    Will hold the I2C bus until reading is complete. Refer to datasheet
+     *          for timing specifications.
+     * 
+     * @param   tempC Pointer for temperature reading. Unit is degree Celcius.
+     * @returns 0 if no errors, -1 if error.
+     */
+    int getTemperature(float *tempC);
+
+    /**
+     * @brief   Start temperature reading.
+     * @details Initiates a temperature reading. Will not hold the bus or block.
+     * @returns 0 if no errors, -1 if error.
+     */
+    int startTemperature(void);
+
+    /**
+     * @brief   Check temperature reading.
+     * @details Checks to see if the temperature reading has been completed.
+                Returns temperature if reading complete.
+     * @note    Must call startTemperature() prior to calling this function. 
+     * @param   tempCx10 Pointer for temperature reading. Unit is 1/10th degree Celcius.
+     * @returns 0 if reading taken, -1 if reading pending.
+     */
+    int checkTemperature(int16_t *tempCx10);
+
+    /**
+     * @brief   Check temperature reading.
+     * @details Checks to see if the temperature reading has been completed.
+                Returns temperature if reading complete.
+     * @note    Must call startTemperature() prior to calling this function. 
+     * @param   tempC Pointer for temperature reading. Unit is degree Celcius.
+     * @returns 0 if reading taken, -1 if reading pending.
+     */
+    int checkTemperature(float *tempC);
+
+    /**
+     * @brief   Get humidity reading.
+     * @details Initiates a humidity reading and blocks until reading has
+     *          been calculated.
+     *
+     * @note    Will hold the I2C bus until reading is complete. Refer to datasheet
+     *          for timing specifications.
+     * 
+     * @param   humidx10 Pointer for humidity reading. Unit is 1/10th percent.
+     * @returns 0 if no errors, -1 if error.
+     */
+    int getHumidity(int16_t *humidx10);
+
+    /**
+     * @brief   Get humidity reading.
+     * @details Initiates a humidity reading and blocks until reading has
+     *          been calculated.
+     *
+     * @note    Will hold the I2C bus until reading is complete. Refer to datasheet
+     *          for timing specifications.
+     * 
+     * @param   humid Pointer for humidity reading. Unit is percent.
+     * @returns 0 if no errors, -1 if error.
+     */
+    int getHumidity(float *humid);
+
+    /**
+     * @brief   Start humidity reading.
+     * @details Initiates a humidity reading. Will not hold the bus or block.
+     * @returns 0 if no errors, -1 if error.
+     */
+    int startHumidity(void);
+
+    /**
+     * @brief   Check humidity reading.
+     * @details Checks to see if the humidity reading has been completed.
+                Returns humidity if reading complete.
+
+     * @note    Must call startHumidity() prior to calling this function. 
+     * @param   humidCx10 Pointer for humidity reading. Unit is 1/10th percent.
+     * @returns 0 if reading taken, -1 if reading pending.
+     */
+    int checkHumidity(int16_t *humidx10);
+
+    /**
+     * @brief   Check humidity reading.
+     * @details Checks to see if the humidity reading has been completed.
+                Returns humidity if reading complete.
+
+     * @note    Must call startHumidity() prior to calling this function. 
+     * @param   humid Pointer for humidity reading. Unit is percent.
+     * @returns 0 if reading taken, -1 if reading pending.
+     */
+    int checkHumidity(float *humid);
+
+    /**
+     * @brief   Get temperature from humidity reading.
+     * @details Gets temperature reading from previous humidity reading.
+     * @note    Must call startHumidity() prior to calling this function. 
+     * @param   tempC Pointer for temperature reading. Unit is degree Celcius.
+     * @returns 0 if reading taken, -1 if reading pending.
+     */
+    int getPrevTemperature(float* tempC);
+
+    /**
+     * @brief   Get temperature from humidity reading.
+     * @details Gets temperature reading from previous humidity reading.
+     * @note    Must call startHumidity() prior to calling this function. 
+     * @param   tempCx10 Pointer for temperature reading. Unit is 1/10th degree Celcius.
+     * @returns 0 if reading taken, -1 if reading pending.
+     */
+    int getPrevTemperature(int16_t *tempCx10);
+
+    /**
+     * @brief   Get firmware revision.
+     * @details Reads the firmware revision, refer to datasheet for codes.
+     * @param   rev Pointer to store firmware revision.
+     * @returns 0 if no errors, -1 if error.
+     */
+    int getRev(char *rev);
+
+    /**
+     * @brief   Control heater.
+     * @details Enable or disable the heater.
+     * @param   enable True to enable heater, false to disable.
+     * @returns 0 if no errors, -1 if error.
+     */
+    int heater(bool enable);
+
+private:
+
+    char crc8(char value, char seed);
+    I2C *i2c_;
+    bool i2c_owner;
+};
+
+#endif /* _SI7020_H_ */