Tim B / MMA8451Q_tb

For D

Dependents:   PWM_2_way_level-r1 StepLogger-Serial

MMA8451Q_tb.cpp@2:34878ff9bbd7, 2014-06-09 (annotated)

Committer:
tim_b
Date:
Mon Jun 09 18:09:51 2014 +0000
Revision:
2:34878ff9bbd7
Parent:
1:c6db5b21ad79 
2014-06-09; Same as before

Who changed what in which revision?

UserRevisionLine numberNew contents of line
tim_b 0:7bc6b6007ed1 1 #include "MMA8451Q_tb.h"
tim_b 0:7bc6b6007ed1 2
tim_b 0:7bc6b6007ed1 3 #define REG_WHO_AM_I 0x0D
tim_b 0:7bc6b6007ed1 4 #define XYZ_DATA_CFG 0x0E
tim_b 0:7bc6b6007ed1 5 #define REG_OUT_X_MSB 0x01
tim_b 0:7bc6b6007ed1 6 #define REG_OUT_Y_MSB 0x03
tim_b 0:7bc6b6007ed1 7 #define REG_OUT_Z_MSB 0x05
tim_b 0:7bc6b6007ed1 8 #define REG_SYSMOD 0x0B
tim_b 0:7bc6b6007ed1 9 #define REG_CTRL_REG1 0x2A
tim_b 0:7bc6b6007ed1 10
tim_b 0:7bc6b6007ed1 11 #define UINT14_MAX 16383
tim_b 0:7bc6b6007ed1 12
tim_b 0:7bc6b6007ed1 13
tim_b 0:7bc6b6007ed1 14 MMA8451Q::MMA8451Q(PinName sda, PinName scl, int addr) : m_i2c(sda, scl), m_addr(addr) {
tim_b 0:7bc6b6007ed1 15 // activate the peripheral
tim_b 0:7bc6b6007ed1 16 uint8_t data[2] = {REG_CTRL_REG1, 0x01};
tim_b 0:7bc6b6007ed1 17 writeRegs(data, 2);
tim_b 0:7bc6b6007ed1 18 }
tim_b 0:7bc6b6007ed1 19
tim_b 0:7bc6b6007ed1 20 MMA8451Q::~MMA8451Q() { }
tim_b 0:7bc6b6007ed1 21
tim_b 0:7bc6b6007ed1 22 uint8_t MMA8451Q::getWhoAmI() {
tim_b 0:7bc6b6007ed1 23 uint8_t who_am_i = 0;
tim_b 0:7bc6b6007ed1 24 readRegs(REG_WHO_AM_I, &who_am_i, 1);
tim_b 0:7bc6b6007ed1 25 return who_am_i;
tim_b 0:7bc6b6007ed1 26 }
tim_b 0:7bc6b6007ed1 27
tim_b 0:7bc6b6007ed1 28 float MMA8451Q::getAccX() {
tim_b 0:7bc6b6007ed1 29 //divide by 4096 b/c MMA output is 4096 counts per g so this f outputs accelorometer value formatted to g (gravity)
tim_b 0:7bc6b6007ed1 30 return (float(getAccAxis(REG_OUT_X_MSB))/4096.0);
tim_b 0:7bc6b6007ed1 31 }
tim_b 0:7bc6b6007ed1 32
tim_b 0:7bc6b6007ed1 33 float MMA8451Q::getAccY() {
tim_b 0:7bc6b6007ed1 34 return (float(getAccAxis(REG_OUT_Y_MSB))/4096.0);
tim_b 0:7bc6b6007ed1 35 }
tim_b 0:7bc6b6007ed1 36
tim_b 0:7bc6b6007ed1 37 float MMA8451Q::getAccZ() {
tim_b 0:7bc6b6007ed1 38 return (float(getAccAxis(REG_OUT_Z_MSB))/4096.0);
tim_b 0:7bc6b6007ed1 39 }
tim_b 0:7bc6b6007ed1 40
tim_b 0:7bc6b6007ed1 41 void MMA8451Q::getAccAllAxis(float * res) {
tim_b 0:7bc6b6007ed1 42 res[0] = getAccX();
tim_b 0:7bc6b6007ed1 43 res[1] = getAccY();
tim_b 0:7bc6b6007ed1 44 res[2] = getAccZ();
tim_b 0:7bc6b6007ed1 45 }
tim_b 0:7bc6b6007ed1 46
tim_b 0:7bc6b6007ed1 47 int16_t MMA8451Q::getAccAxis(uint8_t addr) {
tim_b 0:7bc6b6007ed1 48 int16_t acc;
tim_b 0:7bc6b6007ed1 49 uint8_t res[2];
tim_b 0:7bc6b6007ed1 50 readRegs(addr, res, 2);
tim_b 0:7bc6b6007ed1 51
tim_b 0:7bc6b6007ed1 52 acc = (res[0] << 6) | (res[1] >> 2);
tim_b 0:7bc6b6007ed1 53 if (acc > UINT14_MAX/2)
tim_b 0:7bc6b6007ed1 54 acc -= UINT14_MAX;
tim_b 0:7bc6b6007ed1 55
tim_b 0:7bc6b6007ed1 56 return acc;
tim_b 0:7bc6b6007ed1 57 }
tim_b 0:7bc6b6007ed1 58
tim_b 1:c6db5b21ad79 59 void MMA8451Q::fastRead(float * acc_arr) {
tim_b 1:c6db5b21ad79 60 uint8_t res[6];
tim_b 1:c6db5b21ad79 61 int16_t xt, yt, zt;
tim_b 1:c6db5b21ad79 62
tim_b 1:c6db5b21ad79 63 readRegs(REG_OUT_X_MSB, res, 6);
tim_b 1:c6db5b21ad79 64
tim_b 1:c6db5b21ad79 65 xt = (res[0]<<6)|(res[1]>>2);
tim_b 1:c6db5b21ad79 66 yt = (res[2]<<6)|(res[3]>>2);
tim_b 1:c6db5b21ad79 67 zt = (res[4]<<6)|(res[5]>>2);
tim_b 1:c6db5b21ad79 68
tim_b 1:c6db5b21ad79 69 if (xt > UINT14_MAX/2)
tim_b 1:c6db5b21ad79 70 xt -= UINT14_MAX;
tim_b 1:c6db5b21ad79 71 if (yt > UINT14_MAX/2)
tim_b 1:c6db5b21ad79 72 yt -= UINT14_MAX;
tim_b 1:c6db5b21ad79 73 if (zt > UINT14_MAX/2)
tim_b 1:c6db5b21ad79 74 zt -= UINT14_MAX;
tim_b 1:c6db5b21ad79 75
tim_b 1:c6db5b21ad79 76 acc_arr[0] = float(xt/4096.0);
tim_b 1:c6db5b21ad79 77 acc_arr[1] = float(yt/4096.0);
tim_b 1:c6db5b21ad79 78 acc_arr[2] = float(zt/4096.0);
tim_b 1:c6db5b21ad79 79 }
tim_b 1:c6db5b21ad79 80
tim_b 1:c6db5b21ad79 81
tim_b 0:7bc6b6007ed1 82 void MMA8451Q::readRegs(int addr, uint8_t * data, int len) {
tim_b 0:7bc6b6007ed1 83 char t[1] = {addr};
tim_b 0:7bc6b6007ed1 84 m_i2c.write(m_addr, t, 1, true);
tim_b 0:7bc6b6007ed1 85 m_i2c.read(m_addr, (char *)data, len);
tim_b 0:7bc6b6007ed1 86 }
tim_b 0:7bc6b6007ed1 87
tim_b 0:7bc6b6007ed1 88 void MMA8451Q::writeRegs(uint8_t * data, int len) {
tim_b 0:7bc6b6007ed1 89 m_i2c.write(m_addr, (char *)data, len);
tim_b 0:7bc6b6007ed1 90 }