1 /* Copyright (c) 2010-2011 mbed.org, MIT License
3 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
4 * and associated documentation files (the "Software"), to deal in the Software without
5 * restriction, including without limitation the rights to use, copy, modify, merge, publish,
6 * distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the
7 * Software is furnished to do so, subject to the following conditions:
9 * The above copyright notice and this permission notice shall be included in all copies or
10 * substantial portions of the Software.
12 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
13 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
14 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
15 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
16 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
21 #define INT_SOURCE 0x0C
22 #define REG_WHO_AM_I 0x0D
23 #define HP_FILTER_CUTOFF 0x0F
24 #define PULSE_CFG 0x21
25 #define PULSE_SRC 0x22
26 #define PULSE_THSX 0x23
27 #define PULSE_THSY 0x24
28 #define PULSE_THSZ 0x25
29 #define PULSE_TMLT 0x26
30 #define PULSE_LTCY 0x27
31 #define PULSE_WIND 0x28
32 #define REG_CTRL_REG_1 0x2A
33 #define CTRL_REG2 0x2B
34 #define CTRL_REG4 0x2D
35 #define CTRL_REG5 0x2E
36 #define REG_OUT_X_MSB 0x01
37 #define REG_OUT_Y_MSB 0x03
38 #define REG_OUT_Z_MSB 0x05
40 #define UINT14_MAX 16383
42 MMA8451Q::MMA8451Q(PinName sda, PinName scl, int addr) : m_i2c(sda, scl), m_addr(addr) {
43 // activate the peripheral
44 uint8_t data[2] = {REG_CTRL_REG_1, 0x01};
48 MMA8451Q::~MMA8451Q() { }
50 uint8_t MMA8451Q::getWhoAmI() {
52 readRegs(REG_WHO_AM_I, &who_am_i, 1);
56 float MMA8451Q::getAccX() {
57 //divide by 4096 b/c MMA output is 4096 counts per g so this f outputs accelorometer value formatted to g (gravity)
58 return (float(getAccAxis(REG_OUT_X_MSB))/4096.0);
61 float MMA8451Q::getAccY() {
62 return (float(getAccAxis(REG_OUT_Y_MSB))/4096.0);
65 float MMA8451Q::getAccZ() {
66 return (float(getAccAxis(REG_OUT_Z_MSB))/4096.0);
69 void MMA8451Q::getAccAllAxis(float * res) {
75 int16_t MMA8451Q::getAccAxis(uint8_t addr) {
78 readRegs(addr, res, 2);
80 acc = (res[0] << 6) | (res[1] >> 2);
81 if (acc > UINT14_MAX/2)
87 void MMA8451Q::setDoubleTap(void){
88 //Implemented directly from Freescale's AN4072
89 //Added to MMA8451Q lib
91 uint8_t CTRL_REG1_Data;
93 uint8_t data[2] = {REG_CTRL_REG_1, 0x08};
95 //400 Hz, Standby Mode
98 //Enable X, Y and Z Double Pulse with DPA = 0 no double pulse abort
99 data[0]=PULSE_CFG;data[1]=0x2A;
102 //SetThreshold 3g on X and Y and 5g on Z
103 //Note: Every step is 0.063g
104 //3 g/0.063g = 48 counts
105 //5g/0.063g = 79 counts
106 data[0]=PULSE_THSX;data[1]=0x30;
107 writeRegs(data,2);//Set X Threshold to 3g
108 data[0]=PULSE_THSY;data[1]=0x30;
109 writeRegs(data,2);//Set Y Threshold to 3g
110 data[0]=PULSE_THSZ;data[1]=0x4F;
111 writeRegs(data,2);//Set Z Threshold to 5g
113 //Set Time Limit for Tap Detection to 60 ms LP Mode
114 //Note: 400 Hz ODR, Time step is 1.25 ms per step
115 //60 ms/1.25 ms = 48 counts
116 data[0]=PULSE_TMLT;data[1]=0x30;
117 writeRegs(data,2);//60 ms
119 //Set Latency Time to 200 ms
120 //Note: 400 Hz ODR LPMode, Time step is 2.5 ms per step 00 ms/2.5 ms = 80 counts
121 data[0]=PULSE_LTCY;data[1]=0x50;
122 writeRegs(data,2);//200 ms
124 //Set Time Window for second tap to 300 ms
125 //Note: 400 Hz ODR LP Mode, Time step is 2.5 ms per step
126 //300 ms/2.5 ms = 120 counts
127 data[0]=PULSE_WIND;data[1]=0x78;
128 writeRegs(data,2);//300 ms
130 //Route INT1 to System Interrupt
131 data[0]=CTRL_REG4;data[1]=0x08;
132 writeRegs(data,2);//Enable Pulse Interrupt in System CTRL_REG4
133 data[0]=CTRL_REG5;data[1]=0x08;
134 writeRegs(data,2);//Route Pulse Interrupt to INT1 hardware Pin CTRL_REG5
136 //Set the device to Active Mode
137 readRegs(0x2A,&CTRL_REG1_Data,1);//Read out the contents of the register
138 CTRL_REG1_Data |= 0x01; //Change the value in the register to Active Mode.
139 data[0]=REG_CTRL_REG_1;
140 data[1]=CTRL_REG1_Data;
141 writeRegs(data,2);//Write in the updated value to put the device in Active Mode
145 void MMA8451Q::readRegs(int addr, uint8_t * data, int len) {
146 char t[1] = {(char)addr};
147 m_i2c.write(m_addr, t, 1, true);
148 m_i2c.read(m_addr, (char *)data, len);
153 void MMA8451Q::writeRegs(uint8_t * data, int len) {
154 m_i2c.write(m_addr, (char *)data, len);