Geofrey Marcel / FastPWM

Fork of Erik Olieman's FastPWM library created to add the targets I need.

Fork of FastPWM by Erik -

FastPWM.h@4:a7b9f778c4b4, 2013-08-13 (annotated)

Committer:
Sissors
Date:
Tue Aug 13 16:54:06 2013 +0000
Revision:
4:a7b9f778c4b4
Parent:
3:3094d3806cfc
Child:
6:0f57969697b6
v2.0

; Added KL25Z/LPC11u24 support

; Added prescalers

; Direct tick changes

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 0:f8c1b0ad5371 25 * Library can directly replace standard mbed PWM library. Only limitation is that the maximum PWM period is four times shorter
Sissors 0:f8c1b0ad5371 26 * The maximum achievable period is roughly 40 seconds, I dont think that should be a problem.
Sissors 0:f8c1b0ad5371 27 * Do take into account all PWM objects will run four times faster than default.
Sissors 0:f8c1b0ad5371 28 *
Sissors 0:f8c1b0ad5371 29 * Contrary to the default mbed library, this library takes doubles instead of floats. The compiler will autocast if needed,
Sissors 0:f8c1b0ad5371 30 * 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 31 */
Sissors 4:a7b9f778c4b4 32 class FastPWM : public PwmOut {
Sissors 0:f8c1b0ad5371 33 public:
Sissors 0:f8c1b0ad5371 34 /**
Sissors 0:f8c1b0ad5371 35 * Create a FastPWM object connected to the specified pin
Sissors 0:f8c1b0ad5371 36 *
Sissors 0:f8c1b0ad5371 37 * @param pin - PWM pin to connect to
Sissors 4:a7b9f778c4b4 38 * @param prescaler - Clock prescaler, -1 is dynamic (default), 0 is bit random, everything else normal
Sissors 0:f8c1b0ad5371 39 */
Sissors 4:a7b9f778c4b4 40 FastPWM(PinName pin, int prescaler = -1);
Sissors 0:f8c1b0ad5371 41
Sissors 0:f8c1b0ad5371 42 /**
Sissors 0:f8c1b0ad5371 43 * Set the PWM period, specified in seconds (double), keeping the duty cycle the same.
Sissors 0:f8c1b0ad5371 44 */
Sissors 0:f8c1b0ad5371 45 void period(double seconds);
Sissors 0:f8c1b0ad5371 46
Sissors 0:f8c1b0ad5371 47 /**
Sissors 0:f8c1b0ad5371 48 * Set the PWM period, specified in milli-seconds (int), keeping the duty cycle the same.
Sissors 0:f8c1b0ad5371 49 */
Sissors 0:f8c1b0ad5371 50 void period_ms(int ms);
Sissors 0:f8c1b0ad5371 51
Sissors 0:f8c1b0ad5371 52 /**
Sissors 0:f8c1b0ad5371 53 * Set the PWM period, specified in micro-seconds (int), keeping the duty cycle the same.
Sissors 0:f8c1b0ad5371 54 */
Sissors 0:f8c1b0ad5371 55 void period_us(int us);
Sissors 0:f8c1b0ad5371 56
Sissors 0:f8c1b0ad5371 57 /**
Sissors 0:f8c1b0ad5371 58 * Set the PWM period, specified in micro-seconds (double), keeping the duty cycle the same.
Sissors 0:f8c1b0ad5371 59 */
Sissors 0:f8c1b0ad5371 60 void period_us(double us);
Sissors 0:f8c1b0ad5371 61
Sissors 0:f8c1b0ad5371 62 /**
Sissors 4:a7b9f778c4b4 63 * Set the PWM period, specified in clock ticks, keeping _pulse width_ the same.
Sissors 4:a7b9f778c4b4 64 *
Sissors 4:a7b9f778c4b4 65 * This function can be used if low overhead is required. Do take into account the result is
Sissors 4:a7b9f778c4b4 66 * board (clock frequency) dependent, and this does not keep an equal duty cycle!
Sissors 4:a7b9f778c4b4 67 */
Sissors 4:a7b9f778c4b4 68 void period_ticks(uint32_t ticks);
Sissors 4:a7b9f778c4b4 69
Sissors 4:a7b9f778c4b4 70 /**
Sissors 0:f8c1b0ad5371 71 * Set the PWM pulsewidth, specified in seconds (double), keeping the period the same.
Sissors 0:f8c1b0ad5371 72 */
Sissors 0:f8c1b0ad5371 73 void pulsewidth(double seconds);
Sissors 0:f8c1b0ad5371 74
Sissors 0:f8c1b0ad5371 75 /**
Sissors 0:f8c1b0ad5371 76 * Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same.
Sissors 0:f8c1b0ad5371 77 */
Sissors 0:f8c1b0ad5371 78 void pulsewidth_ms(int ms);
Sissors 0:f8c1b0ad5371 79
Sissors 0:f8c1b0ad5371 80 /**
Sissors 0:f8c1b0ad5371 81 * Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same.
Sissors 0:f8c1b0ad5371 82 */
Sissors 0:f8c1b0ad5371 83 void pulsewidth_us(int us);
Sissors 0:f8c1b0ad5371 84
Sissors 0:f8c1b0ad5371 85 /**
Sissors 0:f8c1b0ad5371 86 * Set the PWM pulsewidth, specified in micro-seconds (double), keeping the period the same.
Sissors 0:f8c1b0ad5371 87 */
Sissors 0:f8c1b0ad5371 88 void pulsewidth_us(double us);
Sissors 0:f8c1b0ad5371 89
Sissors 0:f8c1b0ad5371 90 /**
Sissors 4:a7b9f778c4b4 91 * Set the PWM period, specified in clock ticks, keeping the period the same.
Sissors 4:a7b9f778c4b4 92 *
Sissors 4:a7b9f778c4b4 93 * This function can be used if low overhead is required. Do take into account the result is
Sissors 4:a7b9f778c4b4 94 * board (clock frequency) dependent!
Sissors 4:a7b9f778c4b4 95 */
Sissors 4:a7b9f778c4b4 96 void pulsewidth_ticks(uint32_t ticks);
Sissors 4:a7b9f778c4b4 97
Sissors 4:a7b9f778c4b4 98 /**
Sissors 0:f8c1b0ad5371 99 * Set the ouput duty-cycle, specified as a percentage (double)
Sissors 0:f8c1b0ad5371 100 *
Sissors 0:f8c1b0ad5371 101 * @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 102 */
Sissors 0:f8c1b0ad5371 103 void write(double duty);
Sissors 0:f8c1b0ad5371 104
Sissors 0:f8c1b0ad5371 105 /**
Sissors 0:f8c1b0ad5371 106 * Return the ouput duty-cycle, specified as a percentage (double)
Sissors 0:f8c1b0ad5371 107 *
Sissors 0:f8c1b0ad5371 108 * @param return - A double value representing the output duty-cycle, specified as a percentage.
Sissors 0:f8c1b0ad5371 109 */
Sissors 0:f8c1b0ad5371 110 double read( void );
Sissors 0:f8c1b0ad5371 111
Sissors 0:f8c1b0ad5371 112 /**
Sissors 0:f8c1b0ad5371 113 * An operator shorthand for write()
Sissors 0:f8c1b0ad5371 114 */
Sissors 0:f8c1b0ad5371 115 FastPWM& operator= (double value);
Sissors 0:f8c1b0ad5371 116
Sissors 0:f8c1b0ad5371 117 /**
Sissors 0:f8c1b0ad5371 118 * An operator shorthand for read()
Sissors 0:f8c1b0ad5371 119 */
Sissors 0:f8c1b0ad5371 120 operator double();
Sissors 0:f8c1b0ad5371 121
Sissors 4:a7b9f778c4b4 122 /**
Sissors 4:a7b9f778c4b4 123 * Set the PWM prescaler
Sissors 4:a7b9f778c4b4 124 *
Sissors 4:a7b9f778c4b4 125 * The period of all PWM pins on the same PWM unit have to be reset after using this!
Sissors 4:a7b9f778c4b4 126 *
Sissors 4:a7b9f778c4b4 127 * @param value - The required prescaler. Special values: 0 = lock current prescaler, -1 = use dynamic prescaler
Sissors 4:a7b9f778c4b4 128 * @param return - The prescaler which was set (can differ from requested prescaler if not possible)
Sissors 4:a7b9f778c4b4 129 */
Sissors 4:a7b9f778c4b4 130 int prescaler(int value);
Sissors 4:a7b9f778c4b4 131
Sissors 0:f8c1b0ad5371 132 private:
Sissors 4:a7b9f778c4b4 133 void initFastPWM(void);
Sissors 4:a7b9f778c4b4 134
Sissors 4:a7b9f778c4b4 135 uint32_t setPrescaler( uint32_t reqScale );
Sissors 4:a7b9f778c4b4 136 int calcPrescaler(uint64_t clocks);
Sissors 4:a7b9f778c4b4 137 uint32_t getPeriod( void );
Sissors 4:a7b9f778c4b4 138
Sissors 4:a7b9f778c4b4 139 void updateTicks( uint32_t prescaler );
Sissors 4:a7b9f778c4b4 140 uint32_t bits;
Sissors 4:a7b9f778c4b4 141
Sissors 0:f8c1b0ad5371 142 double _duty;
Sissors 0:f8c1b0ad5371 143
Sissors 4:a7b9f778c4b4 144 double dticks, dticks_us;
Sissors 4:a7b9f778c4b4 145 int iticks_ms, iticks_us;
Sissors 4:a7b9f778c4b4 146
Sissors 4:a7b9f778c4b4 147 bool dynamicPrescaler;
Sissors 4:a7b9f778c4b4 148
Sissors 0:f8c1b0ad5371 149
Sissors 0:f8c1b0ad5371 150 };
Sissors 0:f8c1b0ad5371 151 #endif