Library for the MMA7660 triple axis accelerometer
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Diff: MMA7660.cpp
- Revision:
- 0:7bc29a9ea016
- Child:
- 1:8997a1b348dd
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/MMA7660.cpp Sun Oct 14 08:02:53 2012 +0000 @@ -0,0 +1,123 @@ +#include "MMA7660.h" + +MMA7660::MMA7660(PinName sda, PinName scl, PinName interrupt) : _i2c(sda, scl) +{ + _interrupt = interrupt; + active = false; + samplerate = 120; +} + +//Since the MMA lacks a WHO_AM_I register, we can only check if there is a device that answers to the I2C address +bool MMA7660::testConnection( void ) +{ + if (_i2c.write(MMA7660_ADDRESS, NULL, 0) == 0 ) + return true; + else + return false; +} + +void MMA7660::setActive(bool state) +{ + char modereg = read(MMA7660_MODE_R); + modereg &= ~(1<<0); + + //If it somehow was in testmode, disable that + if (modereg && (1<<2)) { + modereg &= ~(1<<2); + write(MMA7660_MODE_R, modereg); + } + + modereg += state; + write(MMA7660_MODE_R, modereg); +} + +//Add timeout! +void MMA7660::readData(int *data) +{ + if (!active) { + setActive(true); + active = true; + } + + char temp[3]; + bool alert; + + do { + alert = false; + read(MMA7660_XOUT_R, temp, 3); + for (int i = 0; i<3; i++) { + if (temp[i] > 63) + alert = true; + if (temp[i] > 31) + temp[i] += 128+64; + data[i] = (signed char)temp[i]; + } + } while (alert); +} + +void MMA7660::readData(float *data) +{ + int intdata[3]; + readData(intdata); + for (int i = 0; i<3; i++) + data[i] = intdata[i]/MMA7660_SENSITIVITY; +} + +float MMA7660::getX( void ) { + return getSingle(0); + } + +float MMA7660::getY( void ) { + return getSingle(1); + } + +float MMA7660::getZ( void ) { + return getSingle(2); + } + +void MMA7660::write(char address, char data) +{ + char temp[2]; + temp[0]=address; + temp[1]=data; + + _i2c.write(MMA7660_ADDRESS, temp, 2); +} + +char MMA7660::read(char address) +{ + char retval; + _i2c.write(MMA7660_ADDRESS, &address, 1, true); + _i2c.read(MMA7660_ADDRESS, &retval, 1); + return retval; +} + +void MMA7660::read(char address, char *data, int length) +{ + _i2c.write(MMA7660_ADDRESS, &address, 1, true); + _i2c.read(MMA7660_ADDRESS, data, length); +} + +float MMA7660::getSingle( int number ) +{ + if (!active) { + setActive(true); + active = true; + } + + signed char temp; + bool alert; + + do { + alert = false; + temp = read(MMA7660_XOUT_R + number); + if (temp > 63) + alert = true; + if (temp > 31) + temp += 128+64; + } + + while (alert); + + return temp / MMA7660_SENSITIVITY; +} \ No newline at end of file