.info: http://mbed.org/users/aberk/libraries/SCA3000/lsibr6
XxXxXxXxXxXxXxXxXxXxXx SCA3000.cpp XxXxXxXxXxXxXxXxXxXxXx
/**
* @author Aaron Berk
*
* @section LICENSE
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
* @section DESCRIPTION
*
* SCA3000, triple axis, digital interface, accelerometer.
*
* Datasheet:
*
* http://www.sparkfun.com/datasheets/Sensors/Accelerometer/SCA3000-D01.pdf
*/
/**
* Includes
*/
#include "SCA3000.h"
SCA3000::SCA3000(PinName mosi,
PinName miso,
PinName sck,
PinName cs,
PinName nr) : spi_(mosi, miso, sck), nCS_(cs), nR_(nr) {
//1MHz rate.
spi_.frequency(1000000);
//8-bit frame, POL = 0, PHA = 0.
spi_.format(8,0);
//Chip select is active low [so set it high initially].
nCS_ = 1;
//Pulse reset.
nR_ = 0;
wait(0.1);
nR_ = 1;
int status = 0;
//Check whether the device successfully reset by reading
//the CSME bit of the STATUS register.
//0 => no error
//1 => error
status = oneByteRead(SCA3000_STATUS_REG);
//CSME bit = 1... uh oh...
if (status & 0x2) {
}
}
int SCA3000::getRevId(void) {
return oneByteRead(SCA3000_REVID_REG);
}
float SCA3000::getAcceleration(int axis) {
return getCounts(axis) * 0.75;
}
int SCA3000::getCounts(int axis){
int acceleration = 0;
int axis_lsb = 0;
int axis_msb = 0;
switch (axis) {
case SCA3000_X_AXIS:
axis_lsb = oneByteRead(SCA3000_X_LSB);
axis_msb = oneByteRead(SCA3000_X_MSB);
break;
case SCA3000_Y_AXIS:
axis_lsb = oneByteRead(SCA3000_Y_LSB);
axis_msb = oneByteRead(SCA3000_Y_MSB);
break;
case SCA3000_Z_AXIS:
axis_lsb = oneByteRead(SCA3000_Z_LSB);
axis_msb = oneByteRead(SCA3000_Z_MSB);
break;
//An invalid axis value has been passed.
default:
break;
}
int counts = ( axis_msb << 8 | axis_lsb );
//If this looks like nonsense it's because
//the datasheet is completely wrong.
if(counts & 0x8000){
counts = (counts >> 3) & 0x1FFF;
counts = (~counts & 0x1FFF) + 1;
acceleration = counts * -1;
}
else{
counts = (counts >> 3) & 0xFFF;
acceleration = counts;
}
return acceleration;
}
int SCA3000::oneByteRead(int address) {
//Register address sits in the first 6 bits of the transmission.
int tx = ((address << 2) | SCA3000_SPI_READ);
int rx = 0;
nCS_ = 0;
//Send address to read from.
spi_.write(tx);
//Read back contents of address.
rx = spi_.write(0x00);
nCS_ = 1;
return rx;
}
void SCA3000::oneByteWrite(int address, char data) {
//Register address sits in the first 6 bits of the transmission.
int tx = ((address << 2) | SCA3000_SPI_WRITE);
nCS_ = 0;
//Send address to write to.
spi_.write(tx);
//Send data to be written.
spi_.write(data);
nCS_ = 1;
}XxXxXxXxXxXxXxXxXxXxXx SCA3000.h XxXxXxXxXxXxXxXxXxXxXx
/**
* @author Aaron Berk
*
* @section LICENSE
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
* @section DESCRIPTION
*
* SCA3000, triple axis, digital interface, accelerometer.
*
* Datasheet:
*
* http://www.sparkfun.com/datasheets/Sensors/Accelerometer/SCA3000-D01.pdf
*/
#ifndef MBED_SCA3000_H
#define MBED_SCA3000_H
/**
* Includes
*/
#include "mbed.h"
/**
* Defines
*/
//Registers.
#define SCA3000_REVID_REG 0x00
#define SCA3000_STATUS_REG 0x02
#define SCA3000_X_LSB 0x04
#define SCA3000_X_MSB 0x05
#define SCA3000_Y_LSB 0x06
#define SCA3000_Y_MSB 0x07
#define SCA3000_Z_LSB 0x08
#define SCA3000_Z_MSB 0x09
#define SCA3000_SPI_READ 0x00
#define SCA3000_SPI_WRITE 0x02
#define SCA3000_X_AXIS 0x00
#define SCA3000_Y_AXIS 0x01
#define SCA3000_Z_AXIS 0x02
/**
* SCA3000, triple axis, digital interface, accelerometer.
*/
class SCA3000 {
public:
/**
* Constructor.
*
* @param mosi mbed pin to use for MOSI line of SPI interface.
* @param miso mbed pin to use for MISO line of SPI interface.
* @param sck mbed pin to use for SCK line of SPI interface.
* @param cs mbed pin to use for not chip select line of SPI interface.
* @param nr mbed pin to use for the not reset line.
*/
SCA3000(PinName mosi, PinName miso, PinName sck, PinName cs, PinName nr);
/**
* Read the revision ID register on the device.
*
* @return The revision ID number.
*/
int getRevId(void);
/**
* Get the register contents acceleration value for the
* given axis, using the nominal sensitivity values
* found in the datasheet.
*
* @param axis The axis to get acceleration values for.
*
* @return The acceleration on the specified axis in mg.
*/
float getAcceleration(int axis);
/**
* Get the register contents acceleration value for the
* given axis, in counts.
*
* @param axis The axis to get the counts values for.
*
* @return The acceleration on the specified axis in counts.
*/
int getCounts(int axis);
private:
SPI spi_;
DigitalOut nCS_;
DigitalOut nR_;
/**
* Read one byte from a register on the device.
*
* @param address Address of the register to read.
*
* @return The contents of the register address.
*/
int oneByteRead(int address);
/**
* Write one byte to a register on the device.
*
* @param address Address of the register to write to.
* @param data The data to write into the register.
*/
void oneByteWrite(int address, char data);
};
#endif /* MBED_SCA3000_H */XxXxXxXxXxXxXxXxXxXxXx EOF XxXxXxXxXxXxXxXxXxXxXx
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