Diff: LM77.h

Revision:

0:8e812deb9f66

diff -r 000000000000 -r 8e812deb9f66 LM77.h
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+++ b/LM77.h	Sat Jan 10 19:10:40 2015 +0000
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+/* mbed LM77 Library, for an I2C Temperature sensor
+ * Copyright (c) 2015, v01: WH, Initial version
+ * 
+ * The LM77 is a digital temperature sensor and thermal window comparator with an I2C Serial Bus interface. 
+ * The open-drain Interrupt (INT) output becomes active whenever temperature goes outside a programmable window,
+ * while a separate Critical Temperature Alarm (T_CRIT_A) output becomes active when the temperature exceeds a 
+ * programmable critical limit. The INT output can operate in either a comparator or event mode, while the T_CRIT_A 
+ * output operates in comparator mode only. The host can program both the upper and lower limits of the window as 
+ * well as the critical temperature limit. Programmable hysterisis as well as a fault queue are available to minimize 
+ * false tripping. Two pins (A0, A1) are available for address selection. The sensor powers up with default thresholds 
+ * of 2°C THYST, 10°C TLOW, 64°C THIGH, and 80°C T_CRIT.
+ * 
+ * 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 THE
+ * AUTHORS OR COPYRIGHT HOLDERS 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.
+ */
+
+#ifndef MBED_LM77_H
+#define MBED_LM77_H
+
+#include "mbed.h"
+
+/** An interface for the LM77 I2C temperature sensor
+ *
+ * @code
+ * #include "mbed.h"
+ * #include "LM77.h"
+ * 
+ * // I2C Communication
+ * I2C i2c(p28,p27); // SDA, SCL
+ *
+ * // Serial Communication*
+ * Serial pc(USBTX,USBRX);
+ *
+ * //Create an LM77 object at the default address (LM77_SA0)
+ * LM77 sensor(&i2c);
+ *
+ * int main() {
+ *   pc.printf("Hello World!\n");
+ *   if (lm77.getStatus()) {
+ *     pc.printf("LM77 status = Ok\n\r");   
+ *
+ *     pc.printf("Critical Alert temperature from LM77 is %.1f [C]\r\n", lm77.getCritAlertTemp());     
+ *     pc.printf("Low Alert temperature from LM77 is %.1f [C]\r\n", lm77.getLowAlertTemp());     
+ *     pc.printf("High Alert temperature from LM77 is %.1f [C]\r\n", lm77.getHighAlertTemp());             
+ *     pc.printf("Alert Hysteresis from LM77 is %.1f [C]\r\n", lm77.getAlertHyst());  
+ *     wait(1.0);
+ *
+ *#define CA          95.0f     
+ *#define LA           8.0f     
+ *#define HA          15.0f     
+ *#define HY           3.0f     
+ *     lm77.setCritAlertTemp(CA);     
+ *     lm77.setLowAlertTemp(LA);         
+ *     lm77.setHighAlertTemp(HA);
+ *     lm77.setAlertHyst(HY);             
+ * 
+ *     while(1) {
+ *
+ *       // Show Temperature LM77
+ *       //pc.printf("Ambient temperature from LM77 is %.1f [C]\r\n", (float) lm77.getTemperatureInt() / 10.0f);       
+ *       pc.printf("Ambient temperature from LM77 is %.1f [C]\r\n", lm77.getTemperature());     
+ *       wait(1.0);
+ *     } // while
+ *   }
+ *   else {
+ *       pc.printf("LM77 status = not Ok\n\r");            
+ *   } //if
+ * }
+ * @endcode
+ */
+
+// Device I2C Slave addresses
+#define LM77_SA0    0x90
+#define LM77_SA1    0x92
+#define LM77_SA2    0x94
+#define LM77_SA3    0x96
+
+//I2C register addresses
+#define LM77_REG_TEMP    0x00
+#define LM77_REG_CONF    0x01
+#define LM77_REG_THYST   0x02
+#define LM77_REG_TCRIT   0x03
+#define LM77_REG_TLOW    0x04
+#define LM77_REG_THIGH   0x05
+
+//Temp Register
+#define LM77_FLAG_LOW    0x01
+#define LM77_FLAG_HIGH   0x02
+#define LM77_FLAG_CRIT   0x04
+
+#define LM77_FLAG_MSK    0x07
+
+//Config Register
+#define LM77_PWR_ON      0x00
+#define LM77_PWR_DWN     0x01
+#define LM77_INT_CMP     0x00
+#define LM77_INT_EVENT   0x02
+#define LM77_POL_TCRIT_L 0x00
+#define LM77_POL_TCRIT_H 0x04
+#define LM77_POL_INT_L   0x00
+#define LM77_POL_INT_H   0x08
+#define LM77_FQU_1       0x00
+#define LM77_FQU_4       0x10
+
+#define LM77_PWR_MSK       0x01
+#define LM77_INT_MSK       0x02
+#define LM77_POL_TCRIT_MSK 0x04
+#define LM77_POL_INT_MSK   0x08
+#define LM77_FQU_MSK       0x10
+
+/** Create an LM77 Class instance
+ *
+ */ 
+class LM77 {
+
+public:
+   
+    /** Represents the power mode of the LM77
+     */
+    enum PowerMode {
+        POWER_NORMAL,   /**< Chip is enabled and samples every 100ms */
+        POWER_SHUTDOWN  /**< Chip is in low-power shutdown mode */
+    };
+
+    /** Represents INT pin mode of the LM77
+     */
+    enum IntMode {
+        INT_COMPARATOR,  /**< INT pin asserted when temp exceeds an alert threshold, and de-asserted when temp crosses alert hysteresis threshold or when LM77 is read. It will be re-asserted when condition is still true after reading. */
+        INT_EVENT        /**< INT pin asserted when temp reaches an alert threshold or threshold +/- hysteris and only de-asserted when a register has been read. It will be re-asserted when next event occurs. */
+    };
+
+    /** Represents Pin polarity of the LM77
+     */
+    enum PinPolarity {
+        ACTIVE_LOW,     /**< Pin is a logic low when asserted, and a logic high when de-asserted */
+        ACTIVE_HIGH     /**< Pin is a logic high when asserted, and a logic low when de-asserted */
+    };
+
+    /** Represents OS pin fault queue length of the LM77
+     */
+    enum FaultQueue {
+        FAULT_QUEUE_1,   /**< Pins and flags are asserted after 1 fault */
+        FAULT_QUEUE_4,   /**< Pins and flags are asserted after 4 consecutive faults */
+    };
+
+
+   /** Create an LM77 device instance
+     *
+     * @param i2c    I2C Bus 
+     * @param char deviceAddress I2C slaveaddress (defaults to LM77_SA0).
+     */ 
+    LM77(I2C *i2c, char deviceAddress = LM77_SA0);
+
+
+   /** Get the current power mode of the LM77
+     *
+     * @returns The current power mode as a PowerMode enum.
+     */
+    LM77::PowerMode getPowerMode();
+
+   /** Set the power mode of the LM77
+     *
+     * @param mode The new power mode as a PowerMode enum.
+     */
+    void setPowerMode(PowerMode mode);
+
+   /** Get the current INT pin mode of the LM77
+     * Reset value is INT_COMPARATOR            
+     *
+     * @returns The current INT pin mode as an IntMode enum.
+     */
+    LM77::IntMode getIntMode();
+
+   /** Set the INT pin mode of the LM77
+     *
+     * @param mode The new INT pin mode as an IntMode enum.
+     */
+    void setIntMode(IntMode mode);
+
+   /** Get the current INT pin polarity of the LM77
+     * Reset value is ACTIVE_LOW            
+     *
+     * @returns The current INT pin polarity as an PinPolarity enum.
+     */
+    LM77::PinPolarity getIntPolarity();
+
+   /** Set the INT pin polarity of the LM77
+     *
+     * @param polarity The new INT pin polarity as an PinPolarity enum.
+     */
+    void setIntPolarity(PinPolarity polarity);
+
+   /** Get the current T_CRIT_A pin polarity of the LM77
+     * Reset value is ACTIVE_LOW            
+     *
+     * @returns The current T_CRIT_A pin polarity as an PinPolarity enum.
+     */
+    LM77::PinPolarity getTCritPolarity();
+
+   /** Set the T_CRIT_A pin polarity of the LM77
+     *
+     * @param polarity The new T_CRIT_A pin polarity as an PinPolarity enum.
+     */
+    void setTCritPolarity(PinPolarity polarity);
+
+
+   /** Get the current pin and flag fault queue length of the LM77
+     * Reset value is FAULT_QUEUE_1, Pins and flags are asserted after 1 fault
+     *
+     * @returns The current pin and flag fault queue length as an FaultQueue enum.
+     */
+    LM77::FaultQueue getFaultQueue();
+
+   /** Set the pin and flag fault queue length of the LM77
+     *
+     * @param queue The new pin and flag fault queue length as an FaultQueue enum.
+     */
+    void setFaultQueue(FaultQueue queue);
+
+   /** Get the current critical alert temperature threshold of the LM77
+     * Reset value is 80.0 °C.      
+     *
+     * @returns The current crtitcal alert temperature threshold in °C.
+     */
+    float getCritAlertTemp();
+
+   /** Set the Critical alert temperature threshold of the LM77
+     * Reset value is 80.0 °C.   
+     *
+     * @param temp The new Critical alert temperature threshold in °C.
+     */
+    void setCritAlertTemp(float temp);
+
+
+   /** Get the current Low temperature alert threshold of the LM77
+     * Reset value is 10.0 °C.      
+     *
+     * @returns The current Low temperature alert threshold in °C.
+     */
+    float getLowAlertTemp();
+
+   /** Set the current Low temperature alert threshold of the LM77
+     * Reset value is 10.0 °C.      
+     *
+     * @param temp The new Low alert temperature threshold in °C.
+     */
+    void setLowAlertTemp(float temp);
+
+    
+   /** Get the current High temperature alert threshold of the LM77
+     * Reset value is 64.0 °C.      
+     *
+     * @returns The current High temperature alert threshold in °C.
+     */
+    float getHighAlertTemp();
+    
+   /** Set the High temperature alert threshold of the LM77
+     * Reset value is 64.0 °C.   
+     *
+     * @param temp The new High temperature alert threshold in °C.
+     */
+    void setHighAlertTemp(float temp);
+
+
+   /** Get the current alert temperature hysteresis of the LM77
+     * Reset value is 2.0 °C.   
+     *
+     * @returns The current alert temperature hysteresis in °C.
+     */
+    float getAlertHyst();
+
+   /** Set the alert temperature hysteresis of the LM77
+     * Reset value is 2.0 °C.
+     *
+     * @param temp The new alert temperature hysteris in °C.
+     */
+    void setAlertHyst(float temp);
+
+   /** Get Temperature as Int in °Celsius x 10
+     *
+     * @return int Temperature in °Celsius x 10
+     */ 
+    int getTemperatureInt(void);
+    
+   /** Get Temperature as float in °Celsius
+     *
+     * @return float Temperature in °Celsius
+     */ 
+    float getTemperature(void);
+
+   /** Get the Alert flags of the LM77
+     *
+     * @returns The current Alert flags as int.
+     */
+    int getAlertFlags(void);
+
+
+#ifdef MBED_OPERATORS
+    /** A shorthand for Temperature()
+     *
+     * @returns The current temperature measurement in °C.
+     */
+    operator float();
+#endif
+
+   /** Convert Temperature from °Celsius into °Fahrenheit
+     *
+     * @param  float celsius in °Celsius  
+     * @return float temperature in °Fahrenheit
+     */ 
+    float celsiusToFahrenheit(float celsius);
+
+
+   /** Get Status
+     *
+     * @return bool Sensor ready 
+    */ 
+    bool getStatus(void);
+    
+private:
+    //Member variables
+    I2C* _i2c;
+    char _slaveAddress;    
+
+    //Member methods
+   /** Read 8 bit value from register
+     *
+     * @param reg Index of register
+     * @return data value from register
+     */       
+    char _readReg8(char reg);
+
+   /** Write 8 bit value to register
+     *
+     * @param reg Index of register
+     * @param data value to write
+     */     
+    void _writeReg8(char reg, char data);
+
+   /** Read 16 bit value from register
+     * Used for Critical temp threshold, Low and High temp threshold window and Hysteresis
+     *
+     * @param reg Index of register
+     * @return data value from register  
+     */     
+    int16_t _readReg16(char reg);
+    
+   /** Write 16 bit value to register
+     * Used for Critical temp threshold, Low and High temp threshold window and Hysteresis
+     *
+     * @param reg Index of register
+     * @param data value to write
+     */         
+    void _writeReg16(char, int16_t data);
+
+   /** Get Temperature as float in °Celsius
+     * Used for Critical temp threshold, Low and High temp threshold window and Hysteresis 
+     *
+     * @param reg Index of register to read temp value
+     * @return float Temperature in °Celsius
+    */     
+    float _readTempHelper(char reg);
+
+   /** Set Temperature as float in °Celsius
+     * Used for Critical temp threshold, Low and High temp threshold window and Hysteresis
+     *
+     * @param reg Index of register to write temp value
+     * @param temp float Temperature value in °Celsius
+     */        
+    void _writeTempHelper(char reg, float temp);
+};
+
+#endif
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