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Fork of FastPWM by Erik -

Committer:
Sissors
Date:
Mon Mar 17 22:12:58 2014 +0000
Revision:
6:0f57969697b6
Parent:
4:a7b9f778c4b4
Child:
12:4600daab8a83
Changing period now keeps pulsewidth the same instead of duty cycle
;
; KLXX now doesn't give glitches when changing pulsewidth

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Sissors 1:1aed61747ed6 1 /*
Sissors 1:1aed61747ed6 2 .---. _....._
Sissors 1:1aed61747ed6 3 / p `\ .-""`: :`"-.
Sissors 1:1aed61747ed6 4 |__ - | ,' . ' ',
Sissors 1:1aed61747ed6 5 ._> \ /: : ; :,
Sissors 1:1aed61747ed6 6 '-. '\`. . : ' \
Sissors 1:1aed61747ed6 7 `. | .'._.' '._.' '._.'. |
Sissors 1:1aed61747ed6 8 `;-\. : : ' '/,__,
Sissors 1:1aed61747ed6 9 .-'`'._ ' . : _.'.__.'
Sissors 1:1aed61747ed6 10 ((((-'/ `";--..:..--;"` \
Sissors 1:1aed61747ed6 11 .' / \ \
Sissors 1:1aed61747ed6 12 jgs ((((-' ((((-'
Sissors 1:1aed61747ed6 13
Sissors 1:1aed61747ed6 14 Yeah ASCII art turtle more fun than copyright stuff
Sissors 1:1aed61747ed6 15 */
Sissors 1:1aed61747ed6 16
Sissors 1:1aed61747ed6 17
Sissors 0:f8c1b0ad5371 18 #include "mbed.h"
Sissors 0:f8c1b0ad5371 19
Sissors 0:f8c1b0ad5371 20 #ifndef FASTPWM_H
Sissors 0:f8c1b0ad5371 21 #define FASTPWM_H
Sissors 0:f8c1b0ad5371 22
Sissors 0:f8c1b0ad5371 23 /** Library that allows faster and/or higher resolution PWM output
Sissors 0:f8c1b0ad5371 24 *
Sissors 6:0f57969697b6 25 * Library can directly replace standard mbed PWM library.
Sissors 0:f8c1b0ad5371 26 *
Sissors 0:f8c1b0ad5371 27 * Contrary to the default mbed library, this library takes doubles instead of floats. The compiler will autocast if needed,
Sissors 0:f8c1b0ad5371 28 * but do take into account it is done for a reason, your accuracy will otherwise be limitted by the floating point precision.
Sissors 0:f8c1b0ad5371 29 */
Sissors 4:a7b9f778c4b4 30 class FastPWM : public PwmOut {
Sissors 0:f8c1b0ad5371 31 public:
Sissors 0:f8c1b0ad5371 32 /**
Sissors 0:f8c1b0ad5371 33 * Create a FastPWM object connected to the specified pin
Sissors 0:f8c1b0ad5371 34 *
Sissors 0:f8c1b0ad5371 35 * @param pin - PWM pin to connect to
Sissors 4:a7b9f778c4b4 36 * @param prescaler - Clock prescaler, -1 is dynamic (default), 0 is bit random, everything else normal
Sissors 0:f8c1b0ad5371 37 */
Sissors 4:a7b9f778c4b4 38 FastPWM(PinName pin, int prescaler = -1);
Sissors 0:f8c1b0ad5371 39
Sissors 0:f8c1b0ad5371 40 /**
Sissors 6:0f57969697b6 41 * Set the PWM period, specified in seconds (double), keeping the pulsewidth the same.
Sissors 0:f8c1b0ad5371 42 */
Sissors 0:f8c1b0ad5371 43 void period(double seconds);
Sissors 0:f8c1b0ad5371 44
Sissors 0:f8c1b0ad5371 45 /**
Sissors 6:0f57969697b6 46 * Set the PWM period, specified in milli-seconds (int), keeping the pulsewidth the same.
Sissors 0:f8c1b0ad5371 47 */
Sissors 0:f8c1b0ad5371 48 void period_ms(int ms);
Sissors 0:f8c1b0ad5371 49
Sissors 0:f8c1b0ad5371 50 /**
Sissors 6:0f57969697b6 51 * Set the PWM period, specified in micro-seconds (int), keeping the pulsewidth the same.
Sissors 0:f8c1b0ad5371 52 */
Sissors 0:f8c1b0ad5371 53 void period_us(int us);
Sissors 0:f8c1b0ad5371 54
Sissors 0:f8c1b0ad5371 55 /**
Sissors 6:0f57969697b6 56 * Set the PWM period, specified in micro-seconds (double), keeping the pulsewidth the same.
Sissors 0:f8c1b0ad5371 57 */
Sissors 0:f8c1b0ad5371 58 void period_us(double us);
Sissors 0:f8c1b0ad5371 59
Sissors 0:f8c1b0ad5371 60 /**
Sissors 4:a7b9f778c4b4 61 * Set the PWM period, specified in clock ticks, keeping _pulse width_ the same.
Sissors 4:a7b9f778c4b4 62 *
Sissors 4:a7b9f778c4b4 63 * This function can be used if low overhead is required. Do take into account the result is
Sissors 4:a7b9f778c4b4 64 * board (clock frequency) dependent, and this does not keep an equal duty cycle!
Sissors 4:a7b9f778c4b4 65 */
Sissors 4:a7b9f778c4b4 66 void period_ticks(uint32_t ticks);
Sissors 4:a7b9f778c4b4 67
Sissors 4:a7b9f778c4b4 68 /**
Sissors 0:f8c1b0ad5371 69 * Set the PWM pulsewidth, specified in seconds (double), keeping the period the same.
Sissors 0:f8c1b0ad5371 70 */
Sissors 0:f8c1b0ad5371 71 void pulsewidth(double seconds);
Sissors 0:f8c1b0ad5371 72
Sissors 0:f8c1b0ad5371 73 /**
Sissors 0:f8c1b0ad5371 74 * Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same.
Sissors 0:f8c1b0ad5371 75 */
Sissors 0:f8c1b0ad5371 76 void pulsewidth_ms(int ms);
Sissors 0:f8c1b0ad5371 77
Sissors 0:f8c1b0ad5371 78 /**
Sissors 0:f8c1b0ad5371 79 * Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same.
Sissors 0:f8c1b0ad5371 80 */
Sissors 0:f8c1b0ad5371 81 void pulsewidth_us(int us);
Sissors 0:f8c1b0ad5371 82
Sissors 0:f8c1b0ad5371 83 /**
Sissors 0:f8c1b0ad5371 84 * Set the PWM pulsewidth, specified in micro-seconds (double), keeping the period the same.
Sissors 0:f8c1b0ad5371 85 */
Sissors 0:f8c1b0ad5371 86 void pulsewidth_us(double us);
Sissors 0:f8c1b0ad5371 87
Sissors 0:f8c1b0ad5371 88 /**
Sissors 4:a7b9f778c4b4 89 * Set the PWM period, specified in clock ticks, keeping the period the same.
Sissors 4:a7b9f778c4b4 90 *
Sissors 4:a7b9f778c4b4 91 * This function can be used if low overhead is required. Do take into account the result is
Sissors 4:a7b9f778c4b4 92 * board (clock frequency) dependent!
Sissors 4:a7b9f778c4b4 93 */
Sissors 4:a7b9f778c4b4 94 void pulsewidth_ticks(uint32_t ticks);
Sissors 4:a7b9f778c4b4 95
Sissors 4:a7b9f778c4b4 96 /**
Sissors 0:f8c1b0ad5371 97 * Set the ouput duty-cycle, specified as a percentage (double)
Sissors 0:f8c1b0ad5371 98 *
Sissors 0:f8c1b0ad5371 99 * @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%).
Sissors 0:f8c1b0ad5371 100 */
Sissors 0:f8c1b0ad5371 101 void write(double duty);
Sissors 0:f8c1b0ad5371 102
Sissors 0:f8c1b0ad5371 103 /**
Sissors 0:f8c1b0ad5371 104 * Return the ouput duty-cycle, specified as a percentage (double)
Sissors 0:f8c1b0ad5371 105 *
Sissors 0:f8c1b0ad5371 106 * @param return - A double value representing the output duty-cycle, specified as a percentage.
Sissors 0:f8c1b0ad5371 107 */
Sissors 0:f8c1b0ad5371 108 double read( void );
Sissors 0:f8c1b0ad5371 109
Sissors 0:f8c1b0ad5371 110 /**
Sissors 0:f8c1b0ad5371 111 * An operator shorthand for write()
Sissors 0:f8c1b0ad5371 112 */
Sissors 0:f8c1b0ad5371 113 FastPWM& operator= (double value);
Sissors 0:f8c1b0ad5371 114
Sissors 0:f8c1b0ad5371 115 /**
Sissors 0:f8c1b0ad5371 116 * An operator shorthand for read()
Sissors 0:f8c1b0ad5371 117 */
Sissors 0:f8c1b0ad5371 118 operator double();
Sissors 0:f8c1b0ad5371 119
Sissors 4:a7b9f778c4b4 120 /**
Sissors 4:a7b9f778c4b4 121 * Set the PWM prescaler
Sissors 4:a7b9f778c4b4 122 *
Sissors 4:a7b9f778c4b4 123 * The period of all PWM pins on the same PWM unit have to be reset after using this!
Sissors 4:a7b9f778c4b4 124 *
Sissors 4:a7b9f778c4b4 125 * @param value - The required prescaler. Special values: 0 = lock current prescaler, -1 = use dynamic prescaler
Sissors 4:a7b9f778c4b4 126 * @param return - The prescaler which was set (can differ from requested prescaler if not possible)
Sissors 4:a7b9f778c4b4 127 */
Sissors 4:a7b9f778c4b4 128 int prescaler(int value);
Sissors 4:a7b9f778c4b4 129
Sissors 0:f8c1b0ad5371 130 private:
Sissors 4:a7b9f778c4b4 131 void initFastPWM(void);
Sissors 4:a7b9f778c4b4 132
Sissors 4:a7b9f778c4b4 133 uint32_t setPrescaler( uint32_t reqScale );
Sissors 4:a7b9f778c4b4 134 int calcPrescaler(uint64_t clocks);
Sissors 4:a7b9f778c4b4 135 uint32_t getPeriod( void );
Sissors 4:a7b9f778c4b4 136
Sissors 4:a7b9f778c4b4 137 void updateTicks( uint32_t prescaler );
Sissors 4:a7b9f778c4b4 138 uint32_t bits;
Sissors 4:a7b9f778c4b4 139
Sissors 0:f8c1b0ad5371 140 double _duty;
Sissors 0:f8c1b0ad5371 141
Sissors 4:a7b9f778c4b4 142 double dticks, dticks_us;
Sissors 4:a7b9f778c4b4 143 int iticks_ms, iticks_us;
Sissors 4:a7b9f778c4b4 144
Sissors 4:a7b9f778c4b4 145 bool dynamicPrescaler;
Sissors 4:a7b9f778c4b4 146
Sissors 0:f8c1b0ad5371 147
Sissors 0:f8c1b0ad5371 148 };
Sissors 0:f8c1b0ad5371 149 #endif