Federico Luis Pinna Gonzalez / FastAtan2

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Dependents:   FastECompass

FastAtan2.h@3:3f469f0aa3b4, 2016-06-15 (annotated)

Committer:
Cotzo
Date:
Wed Jun 15 13:19:26 2016 +0000
Revision:
3:3f469f0aa3b4
Parent:
2:8bff2a7afea1 
Documentation doxygen

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Cotzo 3:3f469f0aa3b4 1 /**@file FastAtan2.h
Cotzo 3:3f469f0aa3b4 2 *
Cotzo 3:3f469f0aa3b4 3 * Computes the arctangent using Lagrange polynomial approximation with fixed-point arithmetic.
Cotzo 3:3f469f0aa3b4 4 *
Cotzo 3:3f469f0aa3b4 5 *
Cotzo 3:3f469f0aa3b4 6 */
Cotzo 1:9110a3da84c9 7
Cotzo 0:88345d07348b 8 #include "mbed.h"
Cotzo 0:88345d07348b 9
Cotzo 1:9110a3da84c9 10 #ifndef FASTATAN2_H_
Cotzo 1:9110a3da84c9 11 #define FASTATAN2_H_
Cotzo 0:88345d07348b 12
Cotzo 0:88345d07348b 13 #define QFORMAT 15
Cotzo 1:9110a3da84c9 14
Cotzo 1:9110a3da84c9 15 /******************* Constant Q15 ********************/
Cotzo 1:9110a3da84c9 16
Cotzo 1:9110a3da84c9 17 #define PI_Q15 0x19220 // Pi
Cotzo 1:9110a3da84c9 18 #define PI2_Q15 0xC910 // Pi/2
Cotzo 1:9110a3da84c9 19 #define PI4_Q15 0x6488 // Pi/4
Cotzo 1:9110a3da84c9 20 #define PIx2_Q15 0x32440 // 2*Pi
Cotzo 1:9110a3da84c9 21 #define C1 0x1F52 // constante c1 = 0.2447
Cotzo 1:9110a3da84c9 22 #define C2 0x819 // constante c2 = 0.0663
Cotzo 1:9110a3da84c9 23
Cotzo 1:9110a3da84c9 24 /*************** Fixed-point operations ****************/
Cotzo 0:88345d07348b 25
Cotzo 0:88345d07348b 26 #define FSUBI(a,b,q) ((a)-((b)<<(q)))
Cotzo 0:88345d07348b 27 #define FMUL(a,b,q) (((a)*(b))>>(q))
Cotzo 0:88345d07348b 28
Cotzo 1:9110a3da84c9 29 /************** Fixed-point conversions ****************/
Cotzo 1:9110a3da84c9 30
Cotzo 0:88345d07348b 31 #define TOFIX(d,q) ((int32_t)( (d)*(float)(1<<(q)) ))
Cotzo 0:88345d07348b 32 #define TOFLT(a,q) ((float)(a)/(float)(1<<(q)))
Cotzo 1:9110a3da84c9 33
Cotzo 0:88345d07348b 34 #define RAD_Q15_TODEG(rad) ((rad*57)+0x25DC)
Cotzo 0:88345d07348b 35
Cotzo 2:8bff2a7afea1 36 /** Calculates the arc tangent using fixed point q15
Cotzo 2:8bff2a7afea1 37 * @param x Coordinate
Cotzo 3:3f469f0aa3b4 38 * @param y Coordinate
Cotzo 2:8bff2a7afea1 39 * @returns
Cotzo 2:8bff2a7afea1 40 * The function returns the principal arc tangent of y/x, in the interval [0,+pi/2] radians in format Q15
Cotzo 2:8bff2a7afea1 41 */
Cotzo 0:88345d07348b 42
Cotzo 0:88345d07348b 43 int32_t atan_q15(uint32_t x,uint32_t y);
Cotzo 2:8bff2a7afea1 44
Cotzo 2:8bff2a7afea1 45 /** Calculates the arc tangent using fixed point q15
Cotzo 2:8bff2a7afea1 46 * @param x Coordinate
Cotzo 2:8bff2a7afea1 47 * @param y Coordinate
Cotzo 2:8bff2a7afea1 48 * @returns
Cotzo 2:8bff2a7afea1 49 * The function returns the principal arc tangent of y/x, with the correct quadrant in the interval [-pi,+pi] radians in format Q15
Cotzo 2:8bff2a7afea1 50 */
Cotzo 2:8bff2a7afea1 51
Cotzo 0:88345d07348b 52 int32_t atan2_q15(int32_t x,int32_t y);
Cotzo 0:88345d07348b 53
Cotzo 3:3f469f0aa3b4 54 #endif /* FASTATAN2_H_ */
Cotzo 0:88345d07348b 55
Cotzo 3:3f469f0aa3b4 56 /**
Cotzo 3:3f469f0aa3b4 57 *
Cotzo 3:3f469f0aa3b4 58 */