194 строки
4.3 KiB
C++
194 строки
4.3 KiB
C++
#include "MMA7660.h"
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MMA7660::MMA7660(PinName sda, PinName scl, bool active) : _i2c(sda, scl)
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{
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setActive(active);
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samplerate = 64;
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}
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//Since the MMA lacks a WHO_AM_I register, we can only check if there is a device that answers to the I2C address
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bool MMA7660::testConnection( void )
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{
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if (_i2c.write(MMA7660_ADDRESS, NULL, 0) == 0 )
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return true;
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else
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return false;
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}
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void MMA7660::setActive(bool state)
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{
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char modereg = read(MMA7660_MODE_R);
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modereg &= ~(1<<0);
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//If it somehow was in testmode, disable that
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if (modereg && (1<<2)) {
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modereg &= ~(1<<2);
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write(MMA7660_MODE_R, modereg);
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}
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modereg += state;
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write(MMA7660_MODE_R, modereg);
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}
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void MMA7660::readData(int *data)
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{
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if (!active) {
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setActive(true);
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active = true;
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wait(0.012 + 1/samplerate); //Wait until new sample is ready, my experience is that 1/samplerate isnt needed, but datasheet says so
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}
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char temp[3];
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bool alert;
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do {
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alert = false;
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read(MMA7660_XOUT_R, temp, 3);
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for (int i = 0; i<3; i++) {
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if (temp[i] > 63)
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alert = true;
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if (temp[i] > 31)
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temp[i] += 128+64;
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data[i] = (signed char)temp[i];
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}
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} while (alert);
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if (!active)
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setActive(false);
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}
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void MMA7660::readData(float *data)
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{
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int intdata[3];
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readData(intdata);
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for (int i = 0; i<3; i++)
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data[i] = intdata[i]/MMA7660_SENSITIVITY;
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}
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float MMA7660::x( void )
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{
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return getSingle(0);
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}
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float MMA7660::y( void )
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{
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return getSingle(1);
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}
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float MMA7660::z( void )
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{
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return getSingle(2);
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}
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void MMA7660::setSampleRate(int samplerate)
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{
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setActive(false); //Not allowed to be active to change anything
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int rates[] = {120, 64, 32, 16, 8, 4, 2, 1}; //Alowed samplerates (and their number in array is also number required for MMA)
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int sampleLoc = 0, sampleError = 10000, temp;
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for (int i = 0; i<8; i++) {
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temp = abs( rates[i] - samplerate );
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if (temp<sampleError) {
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sampleLoc = i;
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sampleError=temp;
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}
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}
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//Update the samplerate reg
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temp = read(MMA7660_SR_R);
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temp &= ~0x07; //Awake sample rate are lowest 3 bit
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temp |= sampleLoc;
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write(MMA7660_SR_R, temp);
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this->samplerate = rates[sampleLoc];
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setActive(active); //Restore previous active state
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}
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MMA7660::Orientation MMA7660::getSide( void )
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{
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char tiltreg = read(MMA7660_TILT_R);
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//We care about 2 LSBs
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tiltreg &= 0x03;
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if (tiltreg == 0x01)
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return MMA7660::Front;
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if (tiltreg == 0x02)
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return MMA7660::Back;
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return MMA7660::Unknown;
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}
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MMA7660::Orientation MMA7660::getOrientation( void )
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{
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char tiltreg = read(MMA7660_TILT_R);
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//We care about bit 2, 3 and 4 (counting from zero)
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tiltreg &= 0x07<<2;
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tiltreg >>= 2;
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if (tiltreg == 0x01)
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return MMA7660::Left;
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if (tiltreg == 0x02)
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return MMA7660::Right;
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if (tiltreg == 0x05)
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return MMA7660::Down;
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if (tiltreg == 0x06)
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return MMA7660::Up;
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return MMA7660::Unknown;
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}
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//////////////////////////////////////////////
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///////////////PRIVATE////////////////////////
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//////////////////////////////////////////////
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void MMA7660::write(char address, char data)
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{
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char temp[2];
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temp[0]=address;
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temp[1]=data;
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_i2c.write(MMA7660_ADDRESS, temp, 2);
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}
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char MMA7660::read(char address)
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{
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char retval;
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_i2c.write(MMA7660_ADDRESS, &address, 1, true);
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_i2c.read(MMA7660_ADDRESS, &retval, 1);
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return retval;
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}
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void MMA7660::read(char address, char *data, int length)
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{
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_i2c.write(MMA7660_ADDRESS, &address, 1, true);
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_i2c.read(MMA7660_ADDRESS, data, length);
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}
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float MMA7660::getSingle( int number )
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{
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if (!active) {
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setActive(true);
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wait(0.012 + 1/samplerate); //Wait until new sample is ready
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}
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signed char temp;
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bool alert;
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do {
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alert = false;
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temp = read(MMA7660_XOUT_R + number);
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if (temp > 63)
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alert = true;
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if (temp > 31)
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temp += 128+64;
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} while (alert);
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if (!active)
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setActive(false);
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return temp / MMA7660_SENSITIVITY;
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}
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