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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 3 | mjames | 1 | /* |
| 2 | * ap_math.c |
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| 3 | |||
| 4 | * |
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| 5 | * Created on: 31 Jan 2016 |
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| 6 | * Author: Mike |
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| 7 | */ |
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| 8 | #include <math.h> |
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| 9 | #include "stm32l1xx_hal.h" |
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| 10 | #include "ap_math.h" |
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| 11 | /* this is an approximate maths library where all the answers are accurate enough */ |
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| 12 | static uint8_t sintab[90]; |
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| 13 | void ap_init(void) |
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| 14 | { |
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| 15 | uint8_t i; |
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| 16 | for(i=0;i<90;i++) |
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| 17 | { |
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| 18 | sintab[i]=sin(i/180.0*3.14159)*AP_K; |
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| 19 | } |
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| 20 | } |
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| 21 | |||
| 22 | /* returns 255 * sin(ang) where ang is in degrees */ |
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| 23 | int ap_sin(int ang) |
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| 24 | { |
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| 25 | /* wrap into range */ |
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| 26 | while(ang<0) |
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| 27 | { |
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| 28 | ang+= 360; |
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| 29 | } |
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| 30 | while(ang>=360) |
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| 31 | { |
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| 32 | ang-= 360; |
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| 33 | } |
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| 34 | |||
| 35 | if(ang>=0 && ang<90) |
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| 36 | { |
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| 37 | return(sintab[ang]); |
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| 38 | } |
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| 39 | else |
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| 40 | if(ang==90) |
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| 41 | { |
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| 42 | return AP_K; |
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| 43 | } |
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| 44 | else |
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| 45 | if(ang>90 && ang<=180) |
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| 46 | { |
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| 47 | return(sintab[180-ang]); |
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| 48 | } |
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| 49 | else |
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| 50 | if(ang==270) |
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| 51 | { |
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| 52 | return -AP_K; |
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| 53 | } |
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| 54 | if(ang>180 && ang< 270) |
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| 55 | { |
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| 56 | return(-sintab[ang-180]); |
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| 57 | } |
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| 58 | else |
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| 59 | /* ang > 270 and ang < 360 */ |
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| 60 | { |
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| 61 | return(-sintab[360-ang]); |
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| 62 | } |
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| 63 | } |
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| 64 | |||
| 65 | /* returns 255 * cos(ang) where ang is in degrees */ |
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| 66 | int ap_cos(int ang) |
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| 67 | { |
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| 68 | return ap_sin(90-ang); |
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| 69 | } |
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| 70 | |||
| 71 |