LIS2DH.cpp

00001 /*******************************************************************************
00002  * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
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00010  *
00011  * The above copyright notice and this permission notice shall be included
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00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
00015  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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00024  * Products, Inc. Branding Policy.
00025  *
00026  * The mere transfer of this software does not imply any licenses
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00033 
00034 #include "LIS2DH.h"
00035 #include "Streaming.h"
00036 #include "Peripherals.h"
00037 
00038 void lis2dh_int_handler(void);
00039 /** buffer array to hold fifo contents for packetizing
00040 */
00041 uint32_t lis2dh_buffer[LIS2DH_MAX_DATA_SIZE];
00042 
00043 static int debug_int_count = 0;
00044 int16_t motion_cached[3];
00045 LIS2DH *LIS2DH::instance = NULL;
00046 
00047 //******************************************************************************
00048 LIS2DH::LIS2DH(PinName sda, PinName scl, int slaveAddress) : 
00049         slaveAddress(slaveAddress) {
00050   i2c = new I2C(sda, scl);
00051   i2c->frequency(400000);
00052   isOwner = true;
00053   instance = this;
00054 }
00055 
00056 //******************************************************************************
00057 LIS2DH::LIS2DH(I2C *i2c, int slaveAddress) : 
00058         slaveAddress(slaveAddress) {
00059   this->i2c = i2c;
00060   i2c->frequency(400000);
00061   isOwner = false;
00062   instance = this;
00063 }
00064 
00065 //******************************************************************************
00066 LIS2DH::~LIS2DH(void) {
00067   if (isOwner == true) {
00068     delete i2c;
00069   }
00070 }
00071 
00072 //******************************************************************************
00073 int LIS2DH::writeReg(char reg, char value) {
00074   int result;
00075   char cmdData[2] = {(char)reg, value};
00076   result = i2c->write(slaveAddress, cmdData, 2);
00077   if (result != 0)
00078     return -1;
00079   return 0;
00080 }
00081 
00082 //******************************************************************************
00083 int LIS2DH::readReg(char reg, char *value) {
00084   int result;
00085   char cmdData[1] = {(char)reg};
00086 
00087   result = i2c->write(slaveAddress, cmdData, 1);
00088   if (result != 0)
00089     return -1;
00090   result = i2c->read(slaveAddress, value, 1);
00091   if (result != 0)
00092     return -1;
00093   return 0;
00094 }
00095 
00096 //******************************************************************************
00097 static void I2c_Reset(uint8_t index, int speed) {
00098   mxc_i2cm_regs_t *regs = MXC_I2CM_GET_I2CM(index);
00099   /* reset module */
00100   regs->ctrl = MXC_F_I2CM_CTRL_MSTR_RESET_EN;
00101   regs->ctrl = 0;
00102   /* enable tx_fifo and rx_fifo */
00103   regs->ctrl |= (MXC_F_I2CM_CTRL_TX_FIFO_EN | MXC_F_I2CM_CTRL_RX_FIFO_EN);
00104 }
00105 
00106 //******************************************************************************
00107 //  Interrupt handler, this empties the hardware fifo and packetizes it for
00108 //  streaming
00109 void LIS2DH::int_handler(void) {
00110   char fifo_src;
00111   int16_t valueX;
00112   int16_t valueY;
00113   int16_t valueZ;
00114   int num;
00115   int index;
00116 
00117   I2c_Reset(2, 1);
00118   num = 0;
00119   index = 0;
00120   fifo_src = 0;
00121   while ((fifo_src & 0x20) != 0x20) {
00122     get_motion_fifo(&valueX, &valueY, &valueZ);
00123     lis2dh_buffer[index++] = valueX;
00124     lis2dh_buffer[index++] = valueY;
00125     lis2dh_buffer[index++] = valueZ;
00126     readReg(LIS2DH_FIFO_SRC_REG, &fifo_src);
00127     num++;
00128     if (num >= 32)
00129       break;
00130   }
00131   motion_cached[0] = valueX;
00132   motion_cached[1] = valueY;
00133   motion_cached[2] = valueZ;
00134 
00135   StreamPacketUint32(PACKET_LIS2DH, lis2dh_buffer, index);
00136 }
00137 
00138 //******************************************************************************
00139 void LIS2DH::init(void) {
00140   stop();
00141   configure_interrupt();
00142 }
00143 
00144 //******************************************************************************
00145 void LIS2DH::configure_interrupt(void) {
00146   // interrupt enabled on INT1, interrupt active low
00147   lis2dh_ctrl_reg6.all = 0;
00148   lis2dh_ctrl_reg6.bit.I2_INT1 = 1;      // interrupt 1 function enabled on int1 pin
00149   lis2dh_ctrl_reg6.bit.H_LACTIVE = 1;    // interrupt active low
00150   writeReg(LIS2DH_CTRL_REG6, lis2dh_ctrl_reg6.all);
00151 }
00152 
00153 //******************************************************************************
00154 int LIS2DH::initStart(int dataRate, int fifoThreshold) {
00155   __disable_irq();
00156 
00157   configure_interrupt();
00158 
00159   // enable FIFO
00160   lis2dh_ctrl_reg5.all = 0x0;
00161   lis2dh_ctrl_reg5.bit.FIFO_EN = 0x1;
00162   if (writeReg(LIS2DH_CTRL_REG5, lis2dh_ctrl_reg5.all) == -1) {
00163     __enable_irq();
00164     return -1;
00165   }
00166 
00167   // set FIFO to stream mode, trigger select INT1
00168   lis2dh_fifo_ctrl_reg.all = 0x0;
00169   lis2dh_fifo_ctrl_reg.bit.FTH = fifoThreshold;
00170   lis2dh_fifo_ctrl_reg.bit.FM = LIS2DH_FIFOMODE_STREAM;
00171   lis2dh_fifo_ctrl_reg.bit.TR = 0x0;
00172   if (writeReg(LIS2DH_FIFO_CTRL_REG, lis2dh_fifo_ctrl_reg.all) == -1) {
00173     __enable_irq();
00174     return -1;
00175   }
00176 
00177   // set HR (high resolution)
00178   if (writeReg(LIS2DH_CTRL_REG4, 0x8) == -1) {
00179     __enable_irq();
00180     return -1;
00181   }
00182 
00183   // set the data rate, enable all axis
00184   dataRate = dataRate & 0xF;
00185   if (dataRate > 0x9) dataRate = 0x9;
00186   lis2dh_ctrl_reg1.bit.ODR = dataRate; // set the data rate
00187   lis2dh_ctrl_reg1.bit.LPen = 0x0;     // disable low power mode
00188   lis2dh_ctrl_reg1.bit.Zen = 0x1;      // enable z
00189   lis2dh_ctrl_reg1.bit.Yen = 0x1;      // enable y
00190   lis2dh_ctrl_reg1.bit.Xen = 0x1;      // enable x
00191   if (writeReg(LIS2DH_CTRL_REG1, lis2dh_ctrl_reg1.all) == -1) {
00192     __enable_irq();
00193     return -1;
00194   }
00195 
00196   // enable watermark interrupt
00197   lis2dh_ctrl_reg3.all = 0x00;
00198   lis2dh_ctrl_reg3.bit.I1_WTM = 0x1;
00199   if (writeReg(LIS2DH_CTRL_REG3, lis2dh_ctrl_reg3.all) == -1) {
00200     __enable_irq();
00201     return -1;
00202   }
00203   __enable_irq();
00204 
00205   return 0;
00206 }
00207 
00208 //******************************************************************************
00209 int LIS2DH::detect(char *detected) {
00210   char val;
00211   *detected = 0;
00212   if (readReg(LIS2DH_WHO_AM_I, &val) == -1)
00213     return -1;
00214   if (val == LIS2DH_ID) *detected = 1;
00215   return 0;
00216 }
00217 
00218 //******************************************************************************
00219 int LIS2DH::get_motion_cached(int16_t *valueX, int16_t *valueY,
00220                               int16_t *valueZ) {
00221   *valueX = motion_cached[0];
00222   *valueY = motion_cached[1];
00223   *valueZ = motion_cached[2];
00224   return 0;
00225 }
00226 
00227 //******************************************************************************
00228 int LIS2DH::get_motion_fifo(int16_t *valueX, int16_t *valueY, int16_t *valueZ) {
00229   char reg = LIS2DH_OUT_X_L | 0x80;
00230   char values[6];
00231   int i;
00232 
00233   reg = LIS2DH_OUT_X_L;
00234   for (i = 0; i < 6; i++) {
00235     if (readReg(reg, &values[i]) != 0) {
00236       return -1;
00237     }
00238     reg++;
00239   }
00240 
00241   *valueX = ((short)values[1] << 8) + values[0];
00242   *valueY = ((short)values[3] << 8) + values[2];
00243   *valueZ = ((short)values[5] << 8) + values[4];
00244   motion_cached[0] = *valueX;
00245   motion_cached[1] = *valueY;
00246   motion_cached[2] = *valueZ;
00247   return 0;
00248 }
00249 
00250 //******************************************************************************
00251 // 0x33 = read ID
00252 char LIS2DH::readId(void) {
00253   char val;
00254   readReg(LIS2DH_WHO_AM_I, &val);
00255   return val;
00256 }
00257 
00258 //******************************************************************************
00259 void LIS2DH::stop(void) {
00260   __disable_irq();
00261   writeReg(LIS2DH_CTRL_REG3, 0x00); // Disable watermark interrupt
00262   writeReg(LIS2DH_CTRL_REG1, 0x00); // Data rate = 0Hz
00263   writeReg(LIS2DH_FIFO_CTRL_REG,
00264            0x00);                   // set to bypass mode... clears FIFO_SRC_REG
00265   __enable_irq();
00266 }
00267 
00268 //******************************************************************************
00269 void LIS2DHIntHandler(void) {
00270   char value;
00271   // read the data rate axis enable register, if this is zero then just return,
00272   // we are not ready for interrupts
00273   LIS2DH::instance->readReg(LIS2DH_CTRL_REG1, &value);
00274   if (value == 0x0) {
00275     return;
00276   }
00277   LIS2DH::instance->int_handler();
00278 }