Updated OCE 360 Assignment 4
Dependents: Barros_Assignment4
MMA8452Q.cpp
- Committer:
- Kaitlyn_Barros
- Date:
- 2017-12-07
- Revision:
- 2:1d10bcf263d2
- Parent:
- 0:098406435cd2
File content as of revision 2:1d10bcf263d2:
// Library for our MMA8452Q 3-axis accelerometer // Based on the MMA8452Q Arduino Library by Jim Lindblom (SparkFun Electronics) #include "mbed.h" #include "MMA8452Q.h" // Constructor MMA8452Q::MMA8452Q(PinName sda, PinName scl, int addr) : m_i2c(sda, scl), m_addr(addr) { // Initialize members scale = DEFAULT_FSR; } // Destructor MMA8452Q::~MMA8452Q() { } // Initialization bool MMA8452Q::init() { // Check to make sure the chip's ID matches the factory ID uint8_t c = readRegister(REG_WHO_AM_I); if( c != FACTORY_ID ) { return false; } // Set default scale and data rate standby(); setScale(DEFAULT_FSR); setODR(DEFAULT_ODR); active(); return true; } // Set the full-scale range for x, y, and z data void MMA8452Q::setScale(uint8_t fsr) { uint8_t config = readRegister(REG_XYZ_DATA_CFG); scale = fsr; config &= 0xFC; // Mask out FSR bits fsr = fsr >> 2; // Trick to translate scale to FSR bits fsr &= 0x03; // Mask out acceptable FSRs config |= fsr; // Write FSR bits to config byte writeRegister(REG_XYZ_DATA_CFG, config); // Write config back to register } // Set the Output Data Rate void MMA8452Q::setODR(uint8_t odr) { uint8_t ctrl = readRegister(REG_CTRL_REG1); ctrl &= 0xCF; // Mask out data rate bits odr &= 0x07; // Mask out acceptable ODRs ctrl |= (odr << 3); // Write ODR bits to control byte writeRegister(REG_CTRL_REG1, ctrl); // Write control back to register } // Set accelerometer into standby mode void MMA8452Q::standby() { uint8_t c = readRegister(REG_CTRL_REG1); c &= ~(0x01); // Clear bit 0 to go into standby writeRegister(REG_CTRL_REG1, c); // Write back to CONTROL register } // Set accelerometer into active mode void MMA8452Q::active() { uint8_t c = readRegister(REG_CTRL_REG1); c |= 0x01; // Set bit 0 to go into active mode writeRegister(REG_CTRL_REG1, c); // Write back to CONTROL register } // Set accelerometer into standby mode void MMA8452Q::standby1() { uint8_t k = readRegister(REG_FF_MT_CFG); k &= ~(0x07); writeRegister(REG_FF_MT_CFG, k); } void MMA8452Q::active1() { uint8_t k = readRegister(REG_FF_MT_CFG); k |= ~0x07; writeRegister(REG_FF_MT_CFG, k); } // Read X registers float MMA8452Q::readX() { int16_t x = 0; float cx = 0; // Read MSB and LSB from X registers x = readRegister(OUT_X_MSB); x = x << 8; x |= readRegister(OUT_X_LSB); x = x >> 4; // Calculate human readable X cx = (float)x / (float)2048 * (float)(scale); return cx; } // Read Y registers float MMA8452Q::readY() { int16_t y = 0; float cy = 0; // Read MSB and LSB from Y registers y = readRegister(OUT_Y_MSB); y = y << 8; y |= readRegister(OUT_Y_LSB); y = y >> 4; // Calculate human readable Y cy = (float)y / (float)2048 * (float)(scale); return cy; } // Read Z registers float MMA8452Q::readZ() { int16_t z = 0; float cz = 0; // Read MSB and LSB from Z registers z = readRegister(OUT_Z_MSB); z = z << 8; z |= readRegister(OUT_Z_LSB); z = z >> 4; // Calculate human readable Z cz = (float)z / (float)2048 * (float)(scale); return cz; } // Raw read register over I2C uint8_t MMA8452Q::readRegister(uint8_t reg) { uint8_t dev_addr; uint8_t data; // I2C address are bits [6..1] in the transmitted byte, so we shift by 1 dev_addr = m_addr << 1; // Write device address with a trailing 'write' bit m_i2c.start(); m_i2c.write(dev_addr & 0xFE); // Write register address m_i2c.write(reg); // Write a start bit and device address with a trailing 'read' bit m_i2c.start(); m_i2c.write(dev_addr | 0x01); // Read single byte from I2C device data = m_i2c.read(0); m_i2c.stop(); return data; } // Raw write data to a register over I2C void MMA8452Q::writeRegister(uint8_t reg, uint8_t data) { uint8_t dev_addr; // I2C address are bits [6..1] in the transmitted byte, so we shift by 1 dev_addr = m_addr << 1; // Write device address with a trailing 'write' bit m_i2c.start(); m_i2c.write(dev_addr & 0xFE); // Write register address m_i2c.write(reg); // Write the data to the register m_i2c.write(data); m_i2c.stop(); } //IIC_RegWrite(0x15, 0xB8); //Enable Latch, Freefall, X-axis, Y-axis and Z-axis