Works with 8g
Fork of MMA8452 by
MMA8452.cpp
- Committer:
- ashleymills
- Date:
- 2013-10-17
- Revision:
- 6:f6bde04bf8be
- Parent:
- 5:b3d0abd97e55
- Child:
- 8:89272163f395
File content as of revision 6:f6bde04bf8be:
// 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" // 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); // setup read and write addresses to avoid duplication _readAddress = (MMA8452_ADDRESS<<1) | 0x01; _writeAddress = (MMA8452_ADDRESS<<1) & 0xFE; } // Destroys instance Accelerometer_MMA8452::~Accelerometer_MMA8452() { } // Setting the control register bit 1 to true to activate the MMA8452 int Accelerometer_MMA8452::activate() { // set control register 1 to active char init[2] = {CTRL_REG_1,ACTIVE}; // perform write and return error code return m_i2c.write(_writeAddress,init,2); } // Get 'Fast Read Mode' called F_READ. If bit 1 is set '1' then F_READ is active. Fast read will skip LSB when reading xyz // resisters from 0x01 to 0x06. When F_READ is '0' then all 6 registers will be read. int Accelerometer_MMA8452::get_CTRL_Reg1(int* CTRL_Reg) { char mcu_address = (MMA8452_ADDRESS<<1); m_i2c.start(); if( m_i2c.write(_writeAddress) == 0) { return 1; // we failed to write the mcu address on the bus to initiate dialogue } if( m_i2c.write( CTRL_REG_1) == 0) { return 1; // we failed to write 'status' to the chip } m_i2c.start(); if( m_i2c.write( mcu_address | 0x01) == 0) // this is asking to read the slave mcu address - even though it's a 'write' method!!! Crap API... { return 1; // we failed to request a read from that mcu - this really is just writing the mcu vaule on the bus } *CTRL_Reg = m_i2c.read(0); m_i2c.stop(); return 0; } // Setting the control register bit 1 to true to activate the MMA8452 int Accelerometer_MMA8452::standby() { char mcu_address = (MMA8452_ADDRESS<<1); char init[2]; init[0] = CTRL_REG_1; // control register 1 init[1] = STANDBY; // set to standby if(m_i2c.write(mcu_address,init,2) == 0) { // pc.printf("The initialisation worked"); return 0; // return 0 to indicate success } else { // pc.printf("The initialisation failed"); return 1; // crumbs it failed!!! } } // 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 } // Get real time status of device - it can be STANDBY, WAKE or SLEEP int Accelerometer_MMA8452::get_SystemMode(int& deviceSystemMode) { char mcu_address = (MMA8452_ADDRESS<<1); m_i2c.start(); if( m_i2c.write( mcu_address & 0xFE) == 0) // just good practice to force bit 1 to a '0' by ANDing with 0xFE { return 1; // we failed to write the mcu address on the bus to initiate dialogue } if( m_i2c.write( SYSMOD) == 0) { return 1; // we failed to write 'status' to the chip } m_i2c.start(); if( m_i2c.write( mcu_address | 0x01) == 0) // this is asking to read the slave mcu address - even though it's a 'write' method!!! Crap API... { return 1; // we failed to request a read from that mcu - this really is just writing the mcu vaule on the bus } deviceSystemMode = m_i2c.read(0); m_i2c.stop(); return 0; } // Get real time status of device - it can be STANDBY, WAKE or SLEEP int Accelerometer_MMA8452::get_Status(int& deviceStatus) { char mcu_address = (MMA8452_ADDRESS<<1); m_i2c.start(); if( m_i2c.write( mcu_address & 0xFE) == 0) // just good practice to force bit 1 to a '0' by ANDing with 0xFE { return 1; // we failed to write the mcu address on the bus to initiate dialogue } if( m_i2c.write( STATUS) == 0) { return 1; // we failed to write 'status' to the chip } m_i2c.start(); if( m_i2c.write( mcu_address | 0x01) == 0) // this is asking to read the slave mcu address - even though it's a 'write' method!!! Crap API... { return 1; // we failed to request a read from that mcu - this really is just writing the mcu vaule on the bus } deviceStatus = m_i2c.read(0); m_i2c.stop(); return 0; } // Get device ID int Accelerometer_MMA8452::get_DeviceID(int& deviceID) { char mcu_address = (MMA8452_ADDRESS<<1); m_i2c.start(); if( m_i2c.write( mcu_address & 0xFE) == 0) // just good practice to force bit 1 to a '0' by ANDing with 0xFE { return 1; // we failed to write the mcu address on the bus to initiate dialogue } if( m_i2c.write( WHO_AM_I) == 0) { return 1; // we failed to write 'who am i' to the chip } m_i2c.start(); if( m_i2c.write( mcu_address | 0x01) == 0) // this is asking to read the slave mcu address - even though it's a 'write' method!!! Crap API... { return 1; // we failed to request a read from that mcu - this really is just writing the mcu vaule on the bus } deviceID = m_i2c.read(0); m_i2c.stop(); return 0; } /* // Reads x data int Accelerometer_MMA8452::read_x(int& xaxisLSB) { char mcu_address = (MMA8452_ADDRESS<<1); m_i2c.start(); if( m_i2c.write( mcu_address & 0xFE) == 0) // just good practice to force bit 1 to a '0' by ANDing with 0xFE { return 1; // we failed to write the mcu address on the bus to initiate dialogue } if( m_i2c.write( OUT_X_MSB) == 0) { return 1; // we failed to write 'X axis LSB' to the chip } m_i2c.start(); if( m_i2c.write( mcu_address | 0x01) == 0) // this is asking to read the slave mcu address - even though it's a 'write' method!!! Crap API... { return 1; // we failed to request a read from that mcu - this really is just writing the mcu vaule on the bus } xaxisLSB = m_i2c.read(0); m_i2c.stop(); return 0; } */ // Reads x data. This method reads two registers containing the x-axis values from the accelerometer. // It takes a 2 byte char array and copies the register values into the buffer. If it fails the char array // is set to '0'. It returns '0' success '1' fail. This method does nothing to the registers - just returns // the raw data. //int Accelerometer_MMA8452::read_x(int& xaxisLSB) int Accelerometer_MMA8452::read_x_raw(char *xaxis) { char mcu_address = (MMA8452_ADDRESS<<1); // this is the slave address on the bus we want data from char xaxis_buffer[2]; // this will contain data from that register char xaxis_register[1]; xaxis_register[0] = OUT_X_MSB; // this is the register we want to get data from //signed short s = 0; if(m_i2c.write(mcu_address,xaxis_register,1) == 0) { if(m_i2c.read(mcu_address,xaxis_buffer,2) == 0) { //strcpy(xaxis, xaxis_buffer); memcpy(xaxis, xaxis_buffer, 2); //xaxis[0] = 0x00; // make sure the array is set to zero //xaxis[1] = 0x00; //s = *reinterpret_cast<short*>(&xaxis); return 0; // great we got the two octets } else { xaxis[0] = 0x00; // make sure the array is set to zero xaxis[1] = 0x00; return 1; // failed to read the 12 bit x value } } else { xaxis[0] = 0x00; // make sure the array is set to zero xaxis[1] = 0x00; return 1; // failed to write and request the OUT_X_MSB bit } } // Reads y data. This method reads two registers containing the x-axis values from the accelerometer. // It takes a 2 byte char array and copies the register values into the buffer. If it fails the char array // is set to '0'. It returns '0' success '1' fail. This method does nothing to the registers - just returns // the raw data. int Accelerometer_MMA8452::read_y_raw(char *yaxis) { char mcu_address = (MMA8452_ADDRESS<<1); // this is the slave address on the bus we want data from char yaxis_buffer[2]; // this will contain data from that register char yaxis_register[1]; yaxis_register[0] = OUT_Y_MSB; // this is the register we want to get data from //signed short s = 0; if(m_i2c.write(mcu_address,yaxis_register,1) == 0) { if(m_i2c.read(mcu_address,yaxis_buffer,2) == 0) { //strcpy(yaxis, yaxis_buffer); memcpy(yaxis, yaxis_buffer, 2); //yaxis[0] = 0x00; // make sure the array is set to zero //yaxis[1] = 0x00; //s = *reinterpret_cast<short*>(&xaxis); return 0; // great we got the two octets } else { yaxis[0] = 0x00; // make sure the array is set to zero yaxis[1] = 0x00; return 1; // failed to read the 12 bit y value } } else { yaxis[0] = 0x00; // make sure the array is set to zero yaxis[1] = 0x00; return 1; // failed to write and request the OUT_Y_MSB bit } } // Reads z data. This method reads two registers containing the x-axis values from the accelerometer. // It takes a 2 byte char array and copies the register values into the buffer. If it fails the char array // is set to '0'. It returns '0' success '1' fail. This method does nothing to the registers - just returns // the raw data. int Accelerometer_MMA8452::read_z_raw(char *zaxis) { char mcu_address = (MMA8452_ADDRESS<<1); // this is the slave address on the bus we want data from char zaxis_buffer[2]; // this will contain data from that register char zaxis_register[1]; zaxis_register[0] = OUT_Z_MSB; // this is the register we want to get data from //signed short s = 0; if(m_i2c.write(mcu_address,zaxis_register,1) == 0) { //if(m_i2c.read(mcu_address,zaxis_buffer,2) == 0) if(m_i2c.read(mcu_address,zaxis,2) == 0) { //strcpy(yaxis, yaxis_buffer); //memcpy(zaxis, zaxis_buffer, 2); //yaxis[0] = 0x00; // make sure the array is set to zero //yaxis[1] = 0x00; //s = *reinterpret_cast<short*>(&xaxis); return 0; // great we got the two octets } else { zaxis[0] = 0x00; // make sure the array is set to zero zaxis[1] = 0x00; return 1; // failed to read the 12 bit y value } } else { zaxis[0] = 0x00; // make sure the array is set to zero zaxis[1] = 0x00; return 1; // failed to write and request the OUT_Y_MSB bit } } // 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 int y = m_i2c.read(0); // Read the data m_i2c.stop(); return 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 int z = m_i2c.read(0); // Read the data m_i2c.stop(); return z; } // Reads xyz int Accelerometer_MMA8452::read_xyz(char *x, char *y, char *z) { char mcu_address = (MMA8452_ADDRESS <<1); char register_buffer[6] ={0,0,0,0,0,0}; const char Addr_X = OUT_X_MSB; m_i2c.write(mcu_address); // A write to device 0x98 m_i2c.write(MMA8452_ADDRESS, &Addr_X, 1); // Pointer to the OUT_X_MSB register if(m_i2c.write(mcu_address,&Addr_X,1) == 0) { if(m_i2c.read(mcu_address,register_buffer,6) == 0) { *x = register_buffer[1]; *y = register_buffer[3]; *z = register_buffer[5]; return 0; // yahoooooo } else { return 1; // failed oh nooo! } } else { return 1; // failed oh nooo! } } // 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; }