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Diff: MMA8452.cpp
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/MMA8452.cpp Fri Oct 04 14:48:02 2013 +0000 @@ -0,0 +1,193 @@ +// Author: Nicholas Herriot +/* Copyright (c) 2013 Vodafone, MIT License + * + * 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. + */ + +# include "MMA8452.h" + + + +float TILT_XY[64] = {0, 2.69, 5.38, 8.08, 10.81, 13.55, 16.33, 19.16, 22.02, 24.95, 27.95, 31.04, 34.23, 37.54, 41.01, 44.68, 48.59, 52.83, 57.54, 62.95, 69.64, 79.86, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -79.86, -69.64, -62.95, -57.54, -52.83, -48.59, -44.68, -41.01, -37.54, -34.23, -31.04, -27.95, -24.95, -22.02, -19.16, -16.33, -13.55, -10.81, -8.08, -5.38, -2.69}; +float TILT_Z[64] = {90.00, 87.31, 84.62, 81.92, 79.19, 76.45, 73.67, 70.84, 67.98, 65.05, 62.05, 58.96, 55.77, 52.46, 48.99, 45.32, 41.41, 37.17, 32.46, 27.05, 20.36, 10.14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10.14, -20.36, -27.05, -32.46, -37.17, -41.41, -45.32, -48.99, -52.46, -55.77, -58.96, -62.05, -65.05, -67.98, -70.84, -73.67, -76.45, -79.19, -81.92, -84.62}; + + + +// Connect module at I2C address using I2C port pins sda and scl +Accelerometer_MMA8452::Accelerometer_MMA8452(PinName sda, PinName scl,int frequency) : m_i2c(sda, scl): m_frequency(frequency): +{ + //m_i2c.frequency(m_frequency); +} + + +// Destroys instance +Accelerometer_MMA8452::~Accelerometer_MMA8452() +{ + +} + +// Setting the control register bit 1 to true to activate the MMA8452 +int Accelerometer_MMA8452::activate() +{ + char mcu_address = (MMA8452_ADDRESS <1); + char init[2]; + init[0] = CTRL_REG_1; // control register 1 + init[1] = 0x01; // set to active + if(m_i2c.write(mcu_address,init,2) == 0) + { + // pc.printf("The initialisation worked"); + return 0; + } + else + { + // pc.printf("The initialisation failed"); + return 1; + } + +} + + +// Device initialization +void Accelerometer_MMA8452::init() +{ + + write_reg(INTSU_STATUS, 0x10); // automatic interrupt after every measurement + write_reg(SR_STATUS, 0x00); // 120 Samples/Second + write_reg(MODE_STATUS, 0x01); // Active Mode + +} + + +// Reads the tilt angle +void Accelerometer_MMA8452::read_Tilt(float *x, float *y, float *z) +{ + + const char Addr_X = OUT_X_MSB; + char buf[3] = {0,0,0}; + + m_i2c.write(MMA8452_ADDRESS, &Addr_X, 1); // Pointer to the OUT_X_MSB register + m_i2c.read(MMA8452_ADDRESS, buf, 3); // Read register content into buffer with 6bit + + // returns the x, y, z coordinates transformed into full degrees + *x = TILT_XY[(int)buf[0]]; + *y = TILT_XY[(int)buf[1]]; + *z = TILT_Z[(int)buf[2]]; + +} + + +// Reads x data +int Accelerometer_MMA8452::read_x() +{ + char mcu_address = (MMA8452_ADDRESS <1); + + m_i2c.start(); // Start + m_i2c.write(mcu_address); // A write to device 0x98 + m_i2c.write(OUT_X_MSB); // Register to read + m_i2c.start(); + m_i2c.write(mcu_address); // Read from device 0x99 + char x = m_i2c.read(0); // Read the data + m_i2c.stop(); + + return (int)x; + +} + + +// Reads y data +int Accelerometer_MMA8452::read_y() +{ + char mcu_address = (MMA8452_ADDRESS <1); + + m_i2c.start(); // Start + m_i2c.write(mcu_address); // A write to device 0x98 + m_i2c.write(OUT_Y_MSB); // Register to read + m_i2c.start(); + m_i2c.write(mcu_address); // Read from device 0x99 + char y = m_i2c.read(0); // Read the data + m_i2c.stop(); + + return (int)y; + +} + + +// Reads z data +int Accelerometer_MMA8452::read_z() +{ + char mcu_address = (MMA8452_ADDRESS <1); + + m_i2c.start(); // Start + m_i2c.write(mcu_address); // A write to device 0x98 + m_i2c.write(OUT_Z_MSB); // Register to read + m_i2c.start(); + m_i2c.write(mcu_address); // Read from device 0x99 + char z = m_i2c.read(0); // Read the data + m_i2c.stop(); + + return (int)z; + +} + + +// Reads xyz + + + + + // Write register (The device must be placed in Standby Mode to change the value of the registers) +void Accelerometer_MMA8452::write_reg(char addr, char data) +{ + + char cmd[2] = {0, 0}; + + cmd[0] = MODE_STATUS; + cmd[1] = 0x00; // Standby Mode on + m_i2c.write(MMA8452_ADDRESS, cmd, 2); + + cmd[0] = addr; + cmd[1] = data; // New value of the register + m_i2c.write(MMA8452_ADDRESS, cmd, 2); + + cmd[0] = MODE_STATUS; + cmd[1] = 0x01; // Active Mode on + m_i2c.write(MMA8452_ADDRESS, cmd, 2); + +} + + + + // Read from specified MMA7660FC register +char Accelerometer_MMA8452::read_reg(char addr) +{ + + m_i2c.start(); // Start + m_i2c.write(0x98); // A write to device 0x98 + m_i2c.write(addr); // Register to read + m_i2c.start(); + m_i2c.write(0x99); // Read from device 0x99 + char c = m_i2c.read(0); // Read the data + m_i2c.stop(); + + return c; + +} + + + + + +