Generic communication interface between the wireless board (mote) and the sensor board. Any kind of sensor board can be connected to the mote using this specification given it provides a SPI peripheral, one input pin with interrupt capability and one digital output. The sensor board must implement a special register set from which all required information can be retrieved. Protocol: http://is.gd/wuQorh Github: http://is.gd/ySj1L9
MMA8451Q.cpp
00001 /* Copyright (c) 2010-2011 mbed.org, MIT License 00002 * 00003 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software 00004 * and associated documentation files (the "Software"), to deal in the Software without 00005 * restriction, including without limitation the rights to use, copy, modify, merge, publish, 00006 * distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the 00007 * Software is furnished to do so, subject to the following conditions: 00008 * 00009 * The above copyright notice and this permission notice shall be included in all copies or 00010 * substantial portions of the Software. 00011 * 00012 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING 00013 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 00014 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 00015 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 00016 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 00017 */ 00018 00019 #include "MMA8451Q.h" 00020 00021 #define REG_WHO_AM_I 0x0D 00022 #define REG_CTRL_REG_1 0x2A 00023 #define REG_OUT_X_MSB 0x01 00024 #define REG_OUT_Y_MSB 0x03 00025 #define REG_OUT_Z_MSB 0x05 00026 00027 #define UINT14_MAX 16383 00028 00029 MMA8451Q::MMA8451Q(PinName sda, PinName scl, int addr) : m_i2c(sda, scl), m_addr(addr) { 00030 // activate the peripheral 00031 uint8_t data[2] = {REG_CTRL_REG_1, 0x01}; 00032 writeRegs(data, 2); 00033 } 00034 00035 MMA8451Q::~MMA8451Q() { } 00036 00037 uint8_t MMA8451Q::getWhoAmI() { 00038 uint8_t who_am_i = 0; 00039 readRegs(REG_WHO_AM_I, &who_am_i, 1); 00040 return who_am_i; 00041 } 00042 00043 float MMA8451Q::getAccX() { 00044 return (float(getAccAxis(REG_OUT_X_MSB))/4096.0); 00045 } 00046 00047 float MMA8451Q::getAccY() { 00048 return (float(getAccAxis(REG_OUT_Y_MSB))/4096.0); 00049 } 00050 00051 float MMA8451Q::getAccZ() { 00052 return (float(getAccAxis(REG_OUT_Z_MSB))/4096.0); 00053 } 00054 00055 void MMA8451Q::getAccAllAxis(float * res) { 00056 res[0] = getAccX(); 00057 res[1] = getAccY(); 00058 res[2] = getAccZ(); 00059 } 00060 00061 int16_t MMA8451Q::getAccAxis(uint8_t addr) { 00062 int16_t acc; 00063 uint8_t res[2]; 00064 readRegs(addr, res, 2); 00065 00066 acc = (res[0] << 6) | (res[1] >> 2); 00067 if (acc > UINT14_MAX/2) 00068 acc -= UINT14_MAX; 00069 00070 return acc; 00071 } 00072 00073 void MMA8451Q::readRegs(int addr, uint8_t * data, int len) { 00074 char t[1] = {addr}; 00075 m_i2c.write(m_addr, t, 1, true); 00076 m_i2c.read(m_addr, (char *)data, len); 00077 } 00078 00079 void MMA8451Q::writeRegs(uint8_t * data, int len) { 00080 m_i2c.write(m_addr, (char *)data, len); 00081 }
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