WebSVN - FlightCtrl - /branches/V0.68d Code Redesign killagreg/mm3.c

/*

Copyright 2008, by Killagreg

This program (files mm3.c and mm3.h) is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation;
either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.

Please note: The original implementation was done by Niklas Nold.
All the other files for the project "Mikrokopter" by H. Buss are under the license (license_buss.txt) published by www.mikrokopter.de
*/
#include <stdlib.h>
#include <avr/io.h>
#include <avr/interrupt.h>

#include "mm3.h"
#include "main.h"
#include "mymath.h"
#include "fc.h"
#include "timer0.h"
#include "rc.h"
#include "eeprom.h"

#define MAX_AXIS_VALUE 500

typedef struct
{
uint8_t STATE;
uint16_t DRDY;
uint8_t AXIS;
int16_t x_axis;
int16_t y_axis;
int16_t z_axis;
} MM3_working_t;

// MM3 State Machine
#define MM3_STATE_RESET 0
#define MM3_STATE_START_TRANSFER 1
#define MM3_STATE_WAIT_DRDY 2
#define MM3_STATE_DRDY 3
#define MM3_STATE_BYTE2 4

#define MM3_X_AXIS 0x01
#define MM3_Y_AXIS 0x02
#define MM3_Z_AXIS 0x03

#define MM3_PERIOD_32 0x00
#define MM3_PERIOD_64 0x10
#define MM3_PERIOD_128 0x20
#define MM3_PERIOD_256 0x30
#define MM3_PERIOD_512 0x40
#define MM3_PERIOD_1024 0x50
#define MM3_PERIOD_2048 0x60
#define MM3_PERIOD_4096 0x70

MM3_calib_t MM3_calib;
volatile MM3_working_t MM3;
static volatile uint8_t MM3_Timeout = 0;

/*********************************************/
/* Initialize Interface to MM3 Compass */
/*********************************************/
void MM3_Init(void)
{
uint8_t sreg = SREG;

cli();

// Configure Pins for SPI
// set SCK (PB7), MOSI (PB5) as output
DDRB |= (1<<DDB7)|(1<<DDB5);
// set MISO (PB6) as input
DDRB &= ~(1<<DDB6);

// Output Pins PC4->MM3_SS ,PC5->MM3_RESET
DDRC |= (1<<DDC4)|(1<<DDC5);
// set pins permanent to low
PORTC &= ~((1<<PORTC4)|(1<<PORTC5));

// Initialize SPI-Interface
// Enable interrupt (SPIE=1)
// Enable SPI bus (SPE=1)
// MSB transmitted first (DORD = 0)
// Master SPI Mode (MSTR=1)
// Clock polarity low whn idle (CPOL=0)
// clock phase sample at leading edge (CPHA=0)
// clock rate = SYSCLK/128 (SPI2X=0, SPR1=1, SPR0=1) 20MHz/128 = 156.25kHz
SPCR = (1<<SPIE)|(1<<SPE)|(0<<DORD)|(1<<MSTR)|(0<<CPOL)|(0<<CPHA)|(1<<SPR1)|(1<<SPR0);
SPSR &= ~(1<<SPI2X);

// Init Statemachine
MM3.AXIS = MM3_X_AXIS;
MM3.STATE = MM3_STATE_RESET;

// Read calibration from EEprom
MM3_calib.X_off = (int8_t)GetParamByte(PID_MM3_X_OFF);
MM3_calib.Y_off = (int8_t)GetParamByte(PID_MM3_Y_OFF);
MM3_calib.Z_off = (int8_t)GetParamByte(PID_MM3_Z_OFF);
MM3_calib.X_range = (int16_t)GetParamWord(PID_MM3_X_RANGE);
MM3_calib.Y_range = (int16_t)GetParamWord(PID_MM3_Y_RANGE);
MM3_calib.Z_range = (int16_t)GetParamWord(PID_MM3_Z_RANGE);

MM3_Timeout = 0;

SREG = sreg;
}

/*********************************************/
/* Get Data from MM3 */
/*********************************************/
void MM3_Update() // called every 102.4 µs by timer 0 ISR
{
switch (MM3.STATE)
{
case MM3_STATE_RESET:
PORTC &= ~(1<<PORTC4); // select slave
PORTC |= (1<<PORTC5); // PC5 to High, MM3 Reset
MM3.STATE = MM3_STATE_START_TRANSFER;
return;

case MM3_STATE_START_TRANSFER:
PORTC &= ~(1<<PORTC5); // PC4 auf Low (was 102.4 µs at high level)

// write to SPDR triggers automatically the transfer MOSI MISO
// MM3 Period, + AXIS code
switch(MM3.AXIS)
{
case MM3_X_AXIS:
SPDR = MM3_PERIOD_256 + MM3_X_AXIS;
break;
case MM3_Y_AXIS:
SPDR = MM3_PERIOD_256 + MM3_Y_AXIS;
break;
case MM3_Z_AXIS:
SPDR = MM3_PERIOD_256 + MM3_Z_AXIS;
break;
default:
MM3.AXIS = MM3_X_AXIS;
MM3.STATE = MM3_STATE_RESET;
return;
}

// DRDY line is not connected, therefore
// wait before reading data back
MM3.DRDY = SetDelay(8); // wait 8ms for data ready
MM3.STATE = MM3_STATE_WAIT_DRDY;
return;

case MM3_STATE_WAIT_DRDY:
if (CheckDelay(MM3.DRDY))
{
// write something into SPDR to trigger data reading
SPDR = 0x00;
MM3.STATE = MM3_STATE_DRDY;
}
return;
}
}

/*********************************************/
/* Interrupt SPI transfer complete */
/*********************************************/
ISR(SPI_STC_vect)
{
static int8_t tmp;
int16_t value;

switch (MM3.STATE)
{
// 1st byte received
case MM3_STATE_DRDY:
tmp = SPDR; // store 1st byte
SPDR = 0x00; // trigger transfer of 2nd byte
MM3.STATE = MM3_STATE_BYTE2;
return;

case MM3_STATE_BYTE2: // 2nd byte received
value = (int16_t)tmp; // combine the 1st and 2nd byte to a word
value <<= 8; // shift 1st byte to MSB-Position
value |= (int16_t)SPDR; // add 2nd byte

if(abs(value) < MAX_AXIS_VALUE) // ignore spikes
{
switch (MM3.AXIS)
{
case MM3_X_AXIS:
MM3.x_axis = value;
MM3.AXIS = MM3_Y_AXIS;
break;
case MM3_Y_AXIS:
MM3.y_axis = value;
MM3.AXIS = MM3_Z_AXIS;
break;
case MM3_Z_AXIS:
MM3.z_axis = value;
MM3.AXIS = MM3_X_AXIS;
break;
default:
MM3.AXIS = MM3_X_AXIS;
break;
}
}
PORTC |= (1<<PORTC4); // deselect slave
MM3.STATE = MM3_STATE_RESET;
// Update timeout is called every 102.4 µs.
// It takes 2 cycles to write a measurement data request for one axis and
// at at least 8 ms / 102.4 µs = 79 cycles to read the requested data back.
// I.e. 81 cycles * 102.4 µs = 8.3ms per axis.
// The two function accessing the MM3 Data - MM3_Calibrate() and MM3_Heading() -
// decremtent the MM3_Timeout every 100 ms.
// incrementing the counter by 1 every 8.3 ms is sufficient to avoid a timeout.
if ((MM3.x_axis != MM3.y_axis) || (MM3.x_axis != MM3.z_axis) || (MM3.y_axis != MM3.z_axis))
{ // if all axis measurements give diffrent readings the data should be valid
if(MM3_Timeout < 20) MM3_Timeout++;
}
else // something is very strange here
{
if(MM3_Timeout ) MM3_Timeout--;
}
return;

default:
return;
}
}

/*********************************************/
/* Calibrate Compass */
/*********************************************/
void MM3_Calibrate(void)
{
int16_t x_min = 0, x_max = 0, y_min = 0, y_max = 0, z_min = 0, z_max = 0;
uint8_t measurement = 50, beeper = 0;
uint16_t timer;

GRN_ON;
ROT_OFF;

// get maximum and minimum reading of all axis
while (measurement && !MM3_Timeout)
{
if (MM3.x_axis > x_max) x_max = MM3.x_axis;
else if (MM3.x_axis < x_min) x_min = MM3.x_axis;

if (MM3.y_axis > y_max) y_max = MM3.y_axis;
else if (MM3.y_axis < y_min) y_min = MM3.y_axis;

if (MM3.z_axis > z_max) z_max = MM3.z_axis;
else if (MM3.z_axis < z_min) z_min = MM3.z_axis;

if (!beeper)
{
ROT_FLASH;
GRN_FLASH;
BeepTime = 50;
beeper = 50;
}
beeper--;
// loop with period of 10 ms / 100 Hz
timer = SetDelay(10);
while(!CheckDelay(timer));

// If thrust is less than 100, stop calibration with a delay of 0.5 seconds
if (PPM_in[ParamSet.ChannelAssignment[CH_THRUST]] < 100) measurement--;
}
if(!MM3_Timeout)
{
// Rage of all axis
MM3_calib.X_range = (x_max - x_min);
MM3_calib.Y_range = (y_max - y_min);
MM3_calib.Z_range = (z_max - z_min);

// Offset of all axis
MM3_calib.X_off = (x_max + x_min) / 2;
MM3_calib.Y_off = (y_max + y_min) / 2;
MM3_calib.Z_off = (z_max + z_min) / 2;

// save to EEProm
SetParamByte(PID_MM3_X_OFF, (uint8_t)MM3_calib.X_off);
SetParamByte(PID_MM3_Y_OFF, (uint8_t)MM3_calib.Y_off);
SetParamByte(PID_MM3_Z_OFF, (uint8_t)MM3_calib.Z_off);
SetParamWord(PID_MM3_X_RANGE, (uint16_t)MM3_calib.X_range);
SetParamWord(PID_MM3_Y_RANGE, (uint16_t)MM3_calib.Y_range);
SetParamWord(PID_MM3_Z_RANGE, (uint16_t)MM3_calib.Z_range);
}
}

/*********************************************/
/* Calculate north direction (heading) */
/*********************************************/
int16_t MM3_Heading(void)
{
int32_t sin_pitch, cos_pitch, sin_roll, cos_roll, sin_yaw, cos_yaw;
int32_t Hx, Hy, Hz, Hx_corr, Hy_corr;
int16_t angle;
uint16_t div_factor;
int16_t heading;

if (MM3_Timeout)
{
// calibration factor for transforming Gyro Integrals to angular degrees
div_factor = (uint16_t)ParamSet.UserParam3 * 8;

// Offset correction and normalization (values of H are +/- 512)
Hx = (((int32_t)(MM3.x_axis - MM3_calib.X_off)) * 1024) / (int32_t)MM3_calib.X_range;
Hy = (((int32_t)(MM3.y_axis - MM3_calib.Y_off)) * 1024) / (int32_t)MM3_calib.Y_range;
Hz = (((int32_t)(MM3.z_axis - MM3_calib.Z_off)) * 1024) / (int32_t)MM3_calib.Z_range;

// Compensate the angle of the MM3-arrow to the head of the MK by a yaw rotation transformation
// assuming the MM3 board is mounted parallel to the frame.
// User Param 4 is used to define the positive angle from the MM3-arrow to the MK heading
// in a top view counter clockwise direction.
// North is in opposite direction of the small arrow on the MM3 board.
// Therefore 180 deg must be added to that angle.
angle = ((int16_t)ParamSet.UserParam4 + 180);
// wrap angle to interval of 0°- 359°
angle += 360;
angle %= 360;
sin_yaw = (int32_t)(c_sin_8192(angle));
cos_yaw = (int32_t)(c_cos_8192(angle));

Hx_corr = Hx;
Hy_corr = Hy;

// rotate
Hx = (Hx_corr * cos_yaw - Hy_corr * sin_yaw) / 8192;
Hy = (Hx_corr * sin_yaw + Hy_corr * cos_yaw) / 8192;

// tilt compensation

// calibration factor for transforming Gyro Integrals to angular degrees
div_factor = (uint16_t)ParamSet.UserParam3 * 8;

// calculate sinus cosinus of pitch and tilt angle
angle = (IntegralPitch/div_factor);
sin_pitch = (int32_t)(c_sin_8192(angle));
cos_pitch = (int32_t)(c_cos_8192(angle));

angle = (IntegralRoll/div_factor);
sin_roll = (int32_t)(c_sin_8192(angle));
cos_roll = (int32_t)(c_cos_8192(angle));

Hx_corr = Hx * cos_pitch;
Hx_corr -= Hz * sin_pitch;
Hx_corr /= 8192;

Hy_corr = Hy * cos_roll;
Hy_corr += Hz * sin_roll;
Hy_corr /= 8192;

// calculate Heading
heading = c_atan2(Hy_corr, Hx_corr);

// atan returns angular range from -180 deg to 180 deg in counter clockwise notation
// but the compass course is defined in a range from 0 deg to 360 deg clockwise notation.
if (heading < 0) heading = -heading;
else heading = 360 - heading;
}
else // MM3_Timeout = 0 i.e now new data from external board
{
heading = -1;
}
return heading;
}

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