Junaid Ahmed
/
202A_HW1
Configuring sensors dynamically using serial bus from the host computer.
MMA8451Q/MMA8451Q.cpp
- Committer:
- mja054
- Date:
- 2014-02-15
- Revision:
- 2:a422a41dbea1
- Parent:
- 0:1efeb3fc4ba6
File content as of revision 2:a422a41dbea1:
/* Copyright (c) 2010-2011 mbed.org, 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 "MMA8451Q.h" #define INT_SOURCE 0x0C #define REG_WHO_AM_I 0x0D #define HP_FILTER_CUTOFF 0x0F #define PULSE_CFG 0x21 #define PULSE_SRC 0x22 #define PULSE_THSX 0x23 #define PULSE_THSY 0x24 #define PULSE_THSZ 0x25 #define PULSE_TMLT 0x26 #define PULSE_LTCY 0x27 #define PULSE_WIND 0x28 #define REG_CTRL_REG_1 0x2A #define CTRL_REG2 0x2B #define CTRL_REG4 0x2D #define CTRL_REG5 0x2E #define REG_OUT_X_MSB 0x01 #define REG_OUT_Y_MSB 0x03 #define REG_OUT_Z_MSB 0x05 #define UINT14_MAX 16383 MMA8451Q::MMA8451Q(PinName sda, PinName scl, int addr) : m_i2c(sda, scl), m_addr(addr) { // activate the peripheral uint8_t data[2] = {REG_CTRL_REG_1, 0x01}; writeRegs(data, 2); } MMA8451Q::~MMA8451Q() { } uint8_t MMA8451Q::getWhoAmI() { uint8_t who_am_i = 0; readRegs(REG_WHO_AM_I, &who_am_i, 1); return who_am_i; } float MMA8451Q::getAccX() { //divide by 4096 b/c MMA output is 4096 counts per g so this f outputs accelorometer value formatted to g (gravity) return (float(getAccAxis(REG_OUT_X_MSB))/4096.0); } float MMA8451Q::getAccY() { return (float(getAccAxis(REG_OUT_Y_MSB))/4096.0); } float MMA8451Q::getAccZ() { return (float(getAccAxis(REG_OUT_Z_MSB))/4096.0); } void MMA8451Q::getAccAllAxis(float * res) { res[0] = getAccX(); res[1] = getAccY(); res[2] = getAccZ(); } int16_t MMA8451Q::getAccAxis(uint8_t addr) { int16_t acc; uint8_t res[2]; readRegs(addr, res, 2); acc = (res[0] << 6) | (res[1] >> 2); if (acc > UINT14_MAX/2) acc -= UINT14_MAX; return acc; } void MMA8451Q::setDoubleTap(void){ //Implemented directly from Freescale's AN4072 //Added to MMA8451Q lib uint8_t CTRL_REG1_Data; // int adds; uint8_t data[2] = {REG_CTRL_REG_1, 0x08}; //400 Hz, Standby Mode writeRegs(data,2); //Enable X, Y and Z Double Pulse with DPA = 0 no double pulse abort data[0]=PULSE_CFG;data[1]=0x2A; writeRegs(data,2); //SetThreshold 3g on X and Y and 5g on Z //Note: Every step is 0.063g //3 g/0.063g = 48 counts //5g/0.063g = 79 counts data[0]=PULSE_THSX;data[1]=0x30; writeRegs(data,2);//Set X Threshold to 3g data[0]=PULSE_THSY;data[1]=0x30; writeRegs(data,2);//Set Y Threshold to 3g data[0]=PULSE_THSZ;data[1]=0x4F; writeRegs(data,2);//Set Z Threshold to 5g //Set Time Limit for Tap Detection to 60 ms LP Mode //Note: 400 Hz ODR, Time step is 1.25 ms per step //60 ms/1.25 ms = 48 counts data[0]=PULSE_TMLT;data[1]=0x30; writeRegs(data,2);//60 ms //Set Latency Time to 200 ms //Note: 400 Hz ODR LPMode, Time step is 2.5 ms per step 00 ms/2.5 ms = 80 counts data[0]=PULSE_LTCY;data[1]=0x50; writeRegs(data,2);//200 ms //Set Time Window for second tap to 300 ms //Note: 400 Hz ODR LP Mode, Time step is 2.5 ms per step //300 ms/2.5 ms = 120 counts data[0]=PULSE_WIND;data[1]=0x78; writeRegs(data,2);//300 ms //Route INT1 to System Interrupt data[0]=CTRL_REG4;data[1]=0x08; writeRegs(data,2);//Enable Pulse Interrupt in System CTRL_REG4 data[0]=CTRL_REG5;data[1]=0x08; writeRegs(data,2);//Route Pulse Interrupt to INT1 hardware Pin CTRL_REG5 //Set the device to Active Mode readRegs(0x2A,&CTRL_REG1_Data,1);//Read out the contents of the register CTRL_REG1_Data |= 0x01; //Change the value in the register to Active Mode. data[0]=REG_CTRL_REG_1; data[1]=CTRL_REG1_Data; writeRegs(data,2);//Write in the updated value to put the device in Active Mode } void MMA8451Q::readRegs(int addr, uint8_t * data, int len) { char t[1] = {addr}; m_i2c.write(m_addr, t, 1, true); m_i2c.read(m_addr, (char *)data, len); } void MMA8451Q::writeRegs(uint8_t * data, int len) { m_i2c.write(m_addr, (char *)data, len); }