This is a simple device driver for the 3 axis accelerometer MMA8452 that works with mbed.
Dependents: MMA8452_test S05APP3_routeur
MMA8452.h
00001 // Author: Nicholas Herriot 00002 /* Copyright (c) 2013 Vodafone, MIT License 00003 * 00004 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software 00005 * and associated documentation files (the "Software"), to deal in the Software without restriction, 00006 * including without limitation the rights to use, copy, modify, merge, publish, distribute, 00007 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is 00008 * furnished to do so, subject to the following conditions: 00009 * 00010 * The above copyright notice and this permission notice shall be included in all copies or 00011 * substantial portions of the Software. 00012 * 00013 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING 00014 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 00015 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 00016 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 00017 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 00018 */ 00019 00020 // the SparkFun breakout board defaults to 1, set to 0 if SA0 jumper on the bottom of the board is set 00021 // see the Table 10. I2C Device Address Sequence in Freescale MMA8452Q pdf 00022 00023 //#define SA0 1 00024 //#if SA0 00025 //#define MMA8452_ADDRESS 0x3A // SA0 is high, 0x1C if low - it should be 0x1D, but we shift now to save shifting in the code 00026 //#else 00027 //#define MMA8452_ADDRESS 0x1C 00028 //#endif 00029 00030 //#ifndef MBED_MMA8452 00031 00032 //#define MBED_MMA8452 00033 00034 #include "mbed.h" 00035 00036 /** Accelerometer MMA8452 class 00037 * 00038 * Example: 00039 * @code 00040 * 00041 * #include "mbed.h" 00042 * #include "MMA8452.h" 00043 * 00044 * 00045 * Accelerometer_MMA8452 Acc(p28, p27); 00046 * serial pc(USBTX, USBRX); 00047 * 00048 * int main() 00049 * { 00050 * Acc.init(); 00051 * while(1) 00052 * { 00053 * int x=0, y=0, z=0; 00054 * Acc.read_Tilt(&x, &y, &z); 00055 * pc.printf("Tilt x: %2.2f degree \n", x); // Print the tilt orientation of the X axis 00056 * pc.printf("Tilt y: %2.2f degree \n", y); // Print the tilt orientation of the Y axis 00057 * pc.printf("Tilt z: %2.2f degree \n", z); // Print the tilt orientation of the Z axis 00058 * wait(1); 00059 * } 00060 * } 00061 * @endcode 00062 */ 00063 00064 // More info on MCU Master address can be found on section 5.10.1 of http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MMA8452Q 00065 #define SA0 1 00066 #if SA0 00067 #define MMA8452_ADDRESS 0x1D // SA0 is high, 0x1C if low - 00068 #else 00069 #define MMA8452_ADDRESS 0x1C 00070 #endif 00071 00072 // Register descriptions found in section 6 of pdf 00073 #define STATUS 0x00 // Type 'read' : Real time status, should return 0x00 00074 #define OUT_X_MSB 0x01 // Type 'read' : x axis - 8 most significatn bit of a 12 bit sample 00075 #define OUT_X_LSB 0x02 // Type 'read' : x axis - 4 least significatn bit of a 12 bit sample 00076 #define OUT_Y_MSB 0x03 // Type 'read' : y axis - 8 most significatn bit of a 12 bit sample 00077 #define OUT_Y_LSB 0x04 // Type 'read' : y axis - 4 least significatn bit of a 12 bit sample 00078 #define OUT_Z_MSB 0x05 // Type 'read' : z axis - 8 most significatn bit of a 12 bit sample 00079 #define OUT_Z_LSB 0x06 // Type 'read' : z axis - 4 least significatn bit of a 12 bit sample 00080 00081 #define SYSMOD 0x0B // Type 'read' : This tells you if device is active, sleep or standy 0x00=STANDBY 0x01=WAKE 0x02=SLEEP 00082 #define WHO_AM_I 0x0D // Type 'read' : This should return the device id of 0x2A 00083 00084 #define PL_STATUS 0x10 // Type 'read' : This shows portrait landscape mode orientation 00085 #define PL_CFG 0x11 // Type 'read/write' : This allows portrait landscape configuration 00086 #define PL_COUNT 0x12 // Type 'read' : This is the portraint landscape debounce counter 00087 #define PL_BF_ZCOMP 0x13 // Type 'read' : 00088 #define PL_THS_REG 0x14 // Type 'read' : 00089 00090 #define FF_MT_CFG 0X15 // Type 'read/write' : Freefaul motion functional block configuration 00091 #define FF_MT_SRC 0X16 // Type 'read' : Freefaul motion event source register 00092 #define FF_MT_THS 0X17 // Type 'read' : Freefaul motion threshold register 00093 #define FF_COUNT 0X18 // Type 'read' : Freefaul motion debouce counter 00094 00095 #define ASLP_COUNT 0x29 // Type 'read/write' : Counter settings for auto sleep 00096 #define CTRL_REG_1 0x2A // Type 'read/write' : 00097 #define CTRL_REG_2 0x2B // Type 'read/write' : 00098 #define CTRL_REG_3 0x2C // Type 'read/write' : 00099 #define CTRL_REG_4 0x2D // Type 'read/write' : 00100 #define CTRL_REG_5 0x2E // Type 'read/write' : 00101 00102 // Defined in table 13 of the Freescale PDF 00103 #define STANDBY 0x00 // State value returned after a SYSMOD request, it can be in state STANDBY, WAKE or SLEEP 00104 #define WAKE 0x01 // State value returned after a SYSMOD request, it can be in state STANDBY, WAKE or SLEEP 00105 #define SLEEP 0x02 // State value returned after a SYSMOD request, it can be in state STANDBY, WAKE or SLEEP 00106 #define ACTIVE 0x01 // Stage value returned and set in Control Register 1, it can be STANDBY=00, or ACTIVE=01 00107 00108 00109 00110 #define TILT_STATUS 0x03 // Tilt Status (Read only) 00111 #define SRST_STATUS 0x04 // Sample Rate Status Register (Read only) 00112 #define SPCNT_STATUS 0x05 // Sleep Count Register (Read/Write) 00113 #define INTSU_STATUS 0x06 // Interrupt Setup Register 00114 #define MODE_STATUS 0x07 // Mode Register (Read/Write) 00115 #define SR_STATUS 0x08 // Auto-Wake and Active Mode Portrait/Landscape Samples per Seconds Register (Read/Write) 00116 #define PDET_STATUS 0x09 // Tap/Pulse Detection Register (Read/Write) 00117 #define PD_STATUS 0xA // Tap/Pulse Debounce Count Register (Read/Write) 00118 00119 00120 00121 00122 00123 00124 class Accelerometer_MMA8452 00125 { 00126 public: 00127 00128 00129 /** Create an accelerometer object connected to the specified I2C object 00130 * 00131 * @param sda I2C data port 00132 * @param scl I2C8452 clock port 00133 * 00134 */ 00135 Accelerometer_MMA8452(PinName sda, PinName scl, int frequency); 00136 //Accelerometer_MMA8452(PinName sda, PinName scl); 00137 00138 /** Destroys an MMA8452 object 00139 * 00140 */ 00141 ~Accelerometer_MMA8452(); 00142 00143 00144 00145 /** Get system mode of the MMA8452 (not required) 00146 * returns 0 for success in reading the system mode of the chip 00147 * returns 1 for failure in reading the system mode of the chip 00148 * -currently no retries or waiting is done, this method tries 1 time then exits. 00149 * 00150 * This method is used to find out the system mode of the chip ACTIVE = 0x00 or STANDBY = 0x01 00151 */ 00152 int get_SystemMode(int& deviceSystemMode); 00153 00154 00155 00156 /** Get status of the MMA8452 (not required) 00157 * returns 0 for success in reading the status of the chip 00158 * returns 1 for failure in reading the status of the chip 00159 * -currrently no retries or waiting is done, this method tries 1 time then exits. 00160 * 00161 * This method is used to find out the real time status of the device it shows if 00162 * x,y and z values have been overwritten before they have been read since a change happened. 00163 * 00164 */ 00165 int get_Status(int& deviceStatus); 00166 00167 00168 00169 /** Activate the MMA8452 (required) 00170 * returns 0 for success in activating the chip 00171 * returns 1 for failure in activating the chip 00172 * -currrently no retries or waiting is done, this method tries 1 time the exits. 00173 * 00174 * This will set the device 'active' even if it's already active. It's just a way to force that state. 00175 */ 00176 int activate(); 00177 00178 00179 00180 /** Standby the MMA8452 (not required) 00181 * returns 0 for success in activating the chip 00182 * returns 1 for failure in activating the chip 00183 * -currrently no retries or waiting is done, this method tries 1 time the exits. 00184 * 00185 * This will set the device 'standby' even if it's already in standby. It's just a way to force that state. 00186 */ 00187 int standby(); 00188 00189 00190 /** get_CTRL_Reg1 the MMA8452 (not required) 00191 * returns 0 for success in activating the chip 00192 * returns 1 for failure in activating the chip 00193 * -currrently no retries or waiting is done, this method tries 1 time the exits. 00194 * 00195 * This will return the state of the control register 1. This holds and sets values for auto wake, sleep mode 00196 * output data rate, fast read mode and active/standby. More info on 6.7 of pdf for MMA8452 Freescale doc. 00197 */ 00198 int get_CTRL_Reg1(int& CTRL_Reg); 00199 00200 00201 /** Initialization of device MMA8452 (required) 00202 */ 00203 void init(); 00204 00205 /** Read the device ID from the accelerometer 00206 * 00207 * @param *deviceID Value of device - is should be 0x2A 00208 * return 0 for success or 00209 * return 1 for failure. 00210 */ 00211 int get_DeviceID(int& deviceID); 00212 00213 int read_y(); 00214 00215 int read_z(); 00216 00217 /** Read the x register of the MMA8452 00218 * 00219 * @returns The value of x acceleration 00220 */ 00221 int read_x_raw(char *xaxis); 00222 //int read_x(int& xaxisLSB); 00223 /** Read the y register of the MMA8452 00224 * 00225 * @returns The value of y acceleration 00226 */ 00227 int read_y_raw(char *yaxis); 00228 00229 /** Read the z register of the MMA8452 00230 * 00231 * @returns The value of z acceleration 00232 */ 00233 int read_z_raw(char * zaxis); 00234 00235 /** Read the x,y and z registers of the MMA8452 00236 * 00237 * takes a 2 byte char buffer to store the value 00238 * for each axis. 00239 * returns 0 for success, and 1 for failure 00240 * 00241 */ 00242 int read_xyz(char *x, char *y, char *z); 00243 00244 /** Read from specified MMA8452 register 00245 * 00246 * @param addr The internal registeraddress of the MMA8452 00247 * @returns The value of the register 00248 */ 00249 char read_reg(char addr); 00250 00251 /** Write to specified MMA8452 register 00252 * 00253 * @param addr The internal registeraddress of the MMA8452 00254 * @param data New value of the register 00255 */ 00256 void write_reg(char addr, char data); 00257 00258 00259 private: 00260 I2C m_i2c; 00261 int m_frequency; 00262 00263 }; 00264 00265 //#endif
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