Takaaki Numai / FastPWM

inported from local

FastPWM.h@0:60857722c2ff, 2020-03-16 (annotated)

Committer:
NYX
Date:
Mon Mar 16 06:36:03 2020 +0000
Revision:
0:60857722c2ff
initial commit

Who changed what in which revision?

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NYX 0:60857722c2ff 1 /*
NYX 0:60857722c2ff 2 .---. _....._
NYX 0:60857722c2ff 3 / p `\ .-""`: :`"-.
NYX 0:60857722c2ff 4 |__ - | ,' . ' ',
NYX 0:60857722c2ff 5 ._> \ /: : ; :,
NYX 0:60857722c2ff 6 '-. '\`. . : ' \
NYX 0:60857722c2ff 7 `. | .'._.' '._.' '._.'. |
NYX 0:60857722c2ff 8 `;-\. : : ' '/,__,
NYX 0:60857722c2ff 9 .-'`'._ ' . : _.'.__.'
NYX 0:60857722c2ff 10 ((((-'/ `";--..:..--;"` \
NYX 0:60857722c2ff 11 .' / \ \
NYX 0:60857722c2ff 12 jgs ((((-' ((((-'
NYX 0:60857722c2ff 13
NYX 0:60857722c2ff 14 Yeah ASCII art turtle more fun than copyright stuff
NYX 0:60857722c2ff 15 */
NYX 0:60857722c2ff 16
NYX 0:60857722c2ff 17
NYX 0:60857722c2ff 18 #include "mbed.h"
NYX 0:60857722c2ff 19
NYX 0:60857722c2ff 20 #ifndef FASTPWM_H
NYX 0:60857722c2ff 21 #define FASTPWM_H
NYX 0:60857722c2ff 22
NYX 0:60857722c2ff 23 /** Library that allows faster and/or higher resolution PWM output
NYX 0:60857722c2ff 24 *
NYX 0:60857722c2ff 25 * Library can directly replace standard mbed PWM library.
NYX 0:60857722c2ff 26 *
NYX 0:60857722c2ff 27 * Contrary to the default mbed library, this library takes doubles instead of floats. The compiler will autocast if needed,
NYX 0:60857722c2ff 28 * but do take into account it is done for a reason, your accuracy will otherwise be limitted by the floating point precision.
NYX 0:60857722c2ff 29 */
NYX 0:60857722c2ff 30 class FastPWM : public PwmOut {
NYX 0:60857722c2ff 31 public:
NYX 0:60857722c2ff 32 /**
NYX 0:60857722c2ff 33 * Create a FastPWM object connected to the specified pin
NYX 0:60857722c2ff 34 *
NYX 0:60857722c2ff 35 * @param pin - PWM pin to connect to
NYX 0:60857722c2ff 36 * @param prescaler - Clock prescaler, -1 is dynamic (default), 0 is bit random, everything else normal
NYX 0:60857722c2ff 37 */
NYX 0:60857722c2ff 38 FastPWM(PinName pin, int prescaler = -1);
NYX 0:60857722c2ff 39 ~FastPWM();
NYX 0:60857722c2ff 40
NYX 0:60857722c2ff 41 /**
NYX 0:60857722c2ff 42 * Set the PWM period, specified in seconds (double), keeping the pulsewidth the same.
NYX 0:60857722c2ff 43 */
NYX 0:60857722c2ff 44 void period(double seconds);
NYX 0:60857722c2ff 45
NYX 0:60857722c2ff 46 /**
NYX 0:60857722c2ff 47 * Set the PWM period, specified in milli-seconds (int), keeping the pulsewidth the same.
NYX 0:60857722c2ff 48 */
NYX 0:60857722c2ff 49 void period_ms(int ms);
NYX 0:60857722c2ff 50
NYX 0:60857722c2ff 51 /**
NYX 0:60857722c2ff 52 * Set the PWM period, specified in micro-seconds (int), keeping the pulsewidth the same.
NYX 0:60857722c2ff 53 */
NYX 0:60857722c2ff 54 void period_us(int us);
NYX 0:60857722c2ff 55
NYX 0:60857722c2ff 56 /**
NYX 0:60857722c2ff 57 * Set the PWM period, specified in micro-seconds (double), keeping the pulsewidth the same.
NYX 0:60857722c2ff 58 */
NYX 0:60857722c2ff 59 void period_us(double us);
NYX 0:60857722c2ff 60
NYX 0:60857722c2ff 61 /**
NYX 0:60857722c2ff 62 * Set the PWM period, specified in clock ticks, keeping _pulse width_ the same.
NYX 0:60857722c2ff 63 *
NYX 0:60857722c2ff 64 * This function can be used if low overhead is required. Do take into account the result is
NYX 0:60857722c2ff 65 * board (clock frequency) dependent, and this does not keep an equal duty cycle!
NYX 0:60857722c2ff 66 */
NYX 0:60857722c2ff 67 void period_ticks(uint32_t ticks);
NYX 0:60857722c2ff 68
NYX 0:60857722c2ff 69 /**
NYX 0:60857722c2ff 70 * Set the PWM pulsewidth, specified in seconds (double), keeping the period the same.
NYX 0:60857722c2ff 71 */
NYX 0:60857722c2ff 72 void pulsewidth(double seconds);
NYX 0:60857722c2ff 73
NYX 0:60857722c2ff 74 /**
NYX 0:60857722c2ff 75 * Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same.
NYX 0:60857722c2ff 76 */
NYX 0:60857722c2ff 77 void pulsewidth_ms(int ms);
NYX 0:60857722c2ff 78
NYX 0:60857722c2ff 79 /**
NYX 0:60857722c2ff 80 * Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same.
NYX 0:60857722c2ff 81 */
NYX 0:60857722c2ff 82 void pulsewidth_us(int us);
NYX 0:60857722c2ff 83
NYX 0:60857722c2ff 84 /**
NYX 0:60857722c2ff 85 * Set the PWM pulsewidth, specified in micro-seconds (double), keeping the period the same.
NYX 0:60857722c2ff 86 */
NYX 0:60857722c2ff 87 void pulsewidth_us(double us);
NYX 0:60857722c2ff 88
NYX 0:60857722c2ff 89 /**
NYX 0:60857722c2ff 90 * Set the PWM period, specified in clock ticks, keeping the period the same.
NYX 0:60857722c2ff 91 *
NYX 0:60857722c2ff 92 * This function can be used if low overhead is required. Do take into account the result is
NYX 0:60857722c2ff 93 * board (clock frequency) dependent!
NYX 0:60857722c2ff 94 */
NYX 0:60857722c2ff 95 void pulsewidth_ticks(uint32_t ticks);
NYX 0:60857722c2ff 96
NYX 0:60857722c2ff 97 /**
NYX 0:60857722c2ff 98 * Set the ouput duty-cycle, specified as a percentage (double)
NYX 0:60857722c2ff 99 *
NYX 0:60857722c2ff 100 * @param duty - A double value representing the output duty-cycle, specified as a percentage. The value should lie between 0.0 (representing on 0%) and 1.0 (representing on 100%).
NYX 0:60857722c2ff 101 */
NYX 0:60857722c2ff 102 void write(double duty);
NYX 0:60857722c2ff 103
NYX 0:60857722c2ff 104 /**
NYX 0:60857722c2ff 105 * Return the ouput duty-cycle, specified as a percentage (double)
NYX 0:60857722c2ff 106 *
NYX 0:60857722c2ff 107 * @param return - A double value representing the output duty-cycle, specified as a percentage.
NYX 0:60857722c2ff 108 */
NYX 0:60857722c2ff 109 double read( void );
NYX 0:60857722c2ff 110
NYX 0:60857722c2ff 111 /**
NYX 0:60857722c2ff 112 * An operator shorthand for write()
NYX 0:60857722c2ff 113 */
NYX 0:60857722c2ff 114 FastPWM& operator= (double value);
NYX 0:60857722c2ff 115
NYX 0:60857722c2ff 116 /**
NYX 0:60857722c2ff 117 * An operator shorthand for read()
NYX 0:60857722c2ff 118 */
NYX 0:60857722c2ff 119 operator double();
NYX 0:60857722c2ff 120
NYX 0:60857722c2ff 121 /**
NYX 0:60857722c2ff 122 * Set the PWM prescaler
NYX 0:60857722c2ff 123 *
NYX 0:60857722c2ff 124 * The period of all PWM pins on the same PWM unit have to be reset after using this!
NYX 0:60857722c2ff 125 *
NYX 0:60857722c2ff 126 * @param value - The required prescaler. Special values: 0 = lock current prescaler, -1 = use dynamic prescaler
NYX 0:60857722c2ff 127 * @param return - The prescaler which was set (can differ from requested prescaler if not possible)
NYX 0:60857722c2ff 128 */
NYX 0:60857722c2ff 129 int prescaler(int value);
NYX 0:60857722c2ff 130
NYX 0:60857722c2ff 131 private:
NYX 0:60857722c2ff 132 void initFastPWM(void);
NYX 0:60857722c2ff 133
NYX 0:60857722c2ff 134 uint32_t setPrescaler( uint32_t reqScale );
NYX 0:60857722c2ff 135 int calcPrescaler(uint64_t clocks);
NYX 0:60857722c2ff 136 uint32_t getPeriod( void );
NYX 0:60857722c2ff 137
NYX 0:60857722c2ff 138 void updateTicks( uint32_t prescaler );
NYX 0:60857722c2ff 139 uint32_t bits;
NYX 0:60857722c2ff 140
NYX 0:60857722c2ff 141 double _duty;
NYX 0:60857722c2ff 142
NYX 0:60857722c2ff 143 double dticks, dticks_us;
NYX 0:60857722c2ff 144 int iticks_ms, iticks_us;
NYX 0:60857722c2ff 145
NYX 0:60857722c2ff 146 bool dynamicPrescaler;
NYX 0:60857722c2ff 147
NYX 0:60857722c2ff 148 void *fast_obj;
NYX 0:60857722c2ff 149 };
NYX 0:60857722c2ff 150 #endif