Rev 2109 |
Go to most recent revision |
Blame |
Compare with Previous |
Last modification |
View Log
| RSS feed
#ifndef _ANALOG_H
#define _ANALOG_H
#include <inttypes.h>
#include "configuration.h"
/*
About setting constants for different gyros:
Main parameters are positive directions and voltage/angular speed gain.
The "Positive direction" is the rotation direction around an axis where
the corresponding gyro outputs a voltage > the no-rotation voltage.
A gyro is considered, in this code, to be "forward" if its positive
direction is:
- Nose down for pitch
- Left hand side down for roll
- Clockwise seen from above for yaw.
Setting gyro gain correctly: All sensor measurements in analog.c take
place in a cycle, each cycle comprising all sensors. Some sensors are
sampled more than once (oversampled), and the results added.
In the H&I code, the results for pitch and roll are multiplied by 2 (FC1.0)
or 4 (other versions), offset to zero, low pass filtered and then assigned
to the "HiResXXXX" and "AdWertXXXXFilter" variables, where XXXX is nick or
roll. The factor 2 or 4 or whatever is called GYRO_FACTOR_PITCHROLL here.
*/
/*
GYRO_HW_FACTOR is the relation between rotation rate and ADCValue:
ADCValue [units] =
rotational speed [deg/s] *
gyro sensitivity [V / deg/s] *
amplifier gain [units] *
1024 [units] /
3V full range [V]
GYRO_HW_FACTOR is:
gyro sensitivity [V / deg/s] *
amplifier gain [units] *
1024 [units] /
3V full range [V]
Examples:
FC1.3 has 0.67 mV/deg/s gyros and amplifiers with a gain of 5.7:
GYRO_HW_FACTOR = 0.00067 V / deg / s * 5.7 * 1024 / 3V = 1.304 units/(deg/s).
FC2.0 has 6*(3/5) mV/deg/s gyros (they are ratiometric) and no amplifiers:
GYRO_HW_FACTOR = 0.006 V / deg / s * 1 * 1024 * 3V / (3V * 5V) = 1.2288 units/(deg/s).
My InvenSense copter has 2mV/deg/s gyros and no amplifiers:
GYRO_HW_FACTOR = 0.002 V / deg / s * 1 * 1024 / 3V = 0.6827 units/(deg/s)
(only about half as sensitive as V1.3. But it will take about twice the
rotation rate!)
GYRO_HW_FACTOR is given in the makefile.
*/
/*
* How many samples are added in one ADC loop, for pitch&roll and yaw,
* respectively. This is = the number of occurences of each channel in the
* channelsForStates array in analog.c.
*/
#define GYRO_OVERSAMPLING 4
/*
* The product of the 3 above constants. This represents the expected change in ADC value sums for 1 deg/s of rotation rate.
*/
#define GYRO_RATE_FACTOR (GYRO_HW_FACTOR * GYRO_OVERSAMPLING)
/*
* The value of gyro[PITCH/ROLL] for one deg/s = The hardware factor H * the number of samples * multiplier factor.
* Will be about 10 or so for InvenSense, and about 33 for ADXRS610.
*/
/*
* Gyro saturation prevention.
*/
// How far from the end of its range a gyro is considered near-saturated.
#define SENSOR_MIN 32
// Other end of the range (calculated)
#define SENSOR_MAX (GYRO_OVERSAMPLING * 1023 - SENSOR_MIN)
// Max. boost to add "virtually" to gyro signal at total saturation.
#define EXTRAPOLATION_LIMIT 2500
// Slope of the boost (calculated)
#define EXTRAPOLATION_SLOPE (EXTRAPOLATION_LIMIT/SENSOR_MIN)
/*
* This value is subtracted from the gyro noise measurement in each iteration,
* making it return towards zero.
*/
#define GYRO_NOISE_MEASUREMENT_DAMPING 5
#define PITCH 0
#define ROLL 1
#define YAW 2
//#define Z 2
/*
* The values that this module outputs
* These first 2 exported arrays are zero-offset. The "PID" ones are used
* in the attitude control as rotation rates. The "ATT" ones are for
* integration to angles. For the same axis, the PID and ATT variables
* generally have about the same values. There are just some differences
* in filtering, and when a gyro becomes near saturated.
* Maybe this distinction is not really necessary.
*/
extern int16_t gyro_PID[3];
extern int16_t gyro_ATT[3];
extern int16_t gyroD[3];
#define GYRO_D_WINDOW_LENGTH 8
extern uint16_t UBat;
extern uint16_t airspeedVelocity;
// 1:11 voltage divider, 1024 counts per 3V, and result is divided by 3.
#define UBAT_AT_5V (int16_t)((5.0 * (1.0/11.0)) * 1024 / (3.0 * 3))
extern sensorOffset_t gyroOffset;
extern uint16_t airpressureOffset;
/*
* This is not really for external use - but the ENC-03 gyro modules needs it.
*/
//extern volatile int16_t rawGyroSum[3];
/*
* The acceleration values that this module outputs. They are zero based.
*/
//extern int16_t acc[3];
//extern int16_t filteredAcc[3];
// extern volatile int32_t stronglyFilteredAcc[3];
/*
* Diagnostics: Gyro noise level because of motor vibrations. The variables
* only really reflect the noise level when the copter stands still but with
* its motors running.
*/
extern uint16_t gyroNoisePeak[3];
/*
* Air pressure.
* The sensor has a sensitivity of 45 mV/kPa.
* An approximate p(h) formula is = p(h[m])[kPa] = p_0 - 11.95 * 10^-3 * h
* p(h[m])[kPa] = 101.3 - 11.95 * 10^-3 * h
* 11.95 * 10^-3 * h = 101.3 - p[kPa]
* h = (101.3 - p[kPa])/0.01195
* That is: dV = -45 mV * 11.95 * 10^-3 dh = -0.53775 mV / m.
* That is, with 38.02 * 1.024 / 3 steps per mV: -7 steps / m
Display pressures
4165 mV-->1084.7
4090 mV-->1602.4 517.7
3877 mV-->3107.8 1503.4
4165 mV-->1419.1
3503 mV-->208.1
Diff.: 1211.0
Calculated Vout = 5V(.009P-0.095) --> 5V .009P = Vout + 5V 0.095 --> P = (Vout + 5V 0.095)/(5V 0.009)
4165 mV = 5V(0.009P-0.095) P = 103.11 kPa h = -151.4m
4090 mV = 5V(0.009P-0.095) P = 101.44 kPa h = -11.7m 139.7m
3877 mV = 5V(0.009P-0.095) P = 96.7 kPa h = 385m 396.7m
4165 mV = 5V(0.009P-0.095) P = 103.11 kPa h = -151.4m
3503 mV = 5V(0.009P-0.095) P = 88.4 kPa h = 384m Diff: 1079.5m
Pressure at sea level: 101.3 kPa. voltage: 5V * (0.009P-0.095) = 4.0835V
This is OCR2 = 143.15 at 1.5V in --> simple pressure =
*/
#define AIRPRESSURE_WINDOW_LENGTH 32
extern uint16_t airspeedVelocity;
/*
* Flag: Interrupt handler has done all A/D conversion and processing.
*/
extern volatile uint8_t analogDataReady;
void analog_init(void);
/*
* This is really only for use for the ENC-03 code module, which needs to get the raw value
* for its calibration. The raw value should not be used for anything else.
*/
//uint16_t rawGyroValue(uint8_t axis);
/*
* Start the conversion cycle. It will stop automatically.
*/
void startAnalogConversionCycle(void);
/*
* Process the sensor data to update the exported variables. Must be called after each measurement cycle and before the data is used.
*/
void analog_update(void);
/*
* Read gyro and acc.meter calibration from EEPROM.
*/
void analog_setNeutral(void);
/*
* Zero-offset gyros and write the calibration data to EEPROM.
*/
void analog_calibrate(void);
#endif //_ANALOG_H