Michael Ernst Peter / FastPWM

Fork of original FastPWM libary from Sissors.

Dependents:   PM2_Libary PM2_Libary

FastPWM.h@38:b83caa1bcbc7, 2022-03-21 (annotated)

Committer:
pmic
Date:
Mon Mar 21 14:03:24 2022 +0000
Revision:
38:b83caa1bcbc7
Parent:
37:0ca2cf9a1437 
Bugfix.

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 12:4600daab8a83 39 ~FastPWM();
Sissors 0:f8c1b0ad5371 40
Sissors 0:f8c1b0ad5371 41 /**
Sissors 6:0f57969697b6 42 * Set the PWM period, specified in seconds (double), keeping the pulsewidth the same.
Sissors 0:f8c1b0ad5371 43 */
Sissors 0:f8c1b0ad5371 44 void period(double seconds);
Sissors 0:f8c1b0ad5371 45
Sissors 0:f8c1b0ad5371 46 /**
pmic 36:1cc92cba9e04 47 * Set the PWM period, specified in seconds (float), keeping the pulsewidth the same.
pmic 36:1cc92cba9e04 48 */
pmic 36:1cc92cba9e04 49 void period(float seconds);
pmic 36:1cc92cba9e04 50
pmic 36:1cc92cba9e04 51 /**
Sissors 6:0f57969697b6 52 * Set the PWM period, specified in milli-seconds (int), keeping the pulsewidth the same.
Sissors 0:f8c1b0ad5371 53 */
Sissors 0:f8c1b0ad5371 54 void period_ms(int ms);
Sissors 0:f8c1b0ad5371 55
Sissors 0:f8c1b0ad5371 56 /**
Sissors 6:0f57969697b6 57 * Set the PWM period, specified in micro-seconds (int), keeping the pulsewidth the same.
Sissors 0:f8c1b0ad5371 58 */
Sissors 0:f8c1b0ad5371 59 void period_us(int us);
Sissors 0:f8c1b0ad5371 60
Sissors 0:f8c1b0ad5371 61 /**
Sissors 6:0f57969697b6 62 * Set the PWM period, specified in micro-seconds (double), keeping the pulsewidth the same.
Sissors 0:f8c1b0ad5371 63 */
Sissors 0:f8c1b0ad5371 64 void period_us(double us);
Sissors 0:f8c1b0ad5371 65
Sissors 0:f8c1b0ad5371 66 /**
Sissors 4:a7b9f778c4b4 67 * Set the PWM period, specified in clock ticks, keeping _pulse width_ the same.
Sissors 4:a7b9f778c4b4 68 *
Sissors 4:a7b9f778c4b4 69 * This function can be used if low overhead is required. Do take into account the result is
Sissors 4:a7b9f778c4b4 70 * board (clock frequency) dependent, and this does not keep an equal duty cycle!
Sissors 4:a7b9f778c4b4 71 */
Sissors 4:a7b9f778c4b4 72 void period_ticks(uint32_t ticks);
Sissors 4:a7b9f778c4b4 73
Sissors 4:a7b9f778c4b4 74 /**
Sissors 0:f8c1b0ad5371 75 * Set the PWM pulsewidth, specified in seconds (double), keeping the period the same.
Sissors 0:f8c1b0ad5371 76 */
Sissors 0:f8c1b0ad5371 77 void pulsewidth(double seconds);
Sissors 0:f8c1b0ad5371 78
Sissors 0:f8c1b0ad5371 79 /**
Sissors 0:f8c1b0ad5371 80 * Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same.
Sissors 0:f8c1b0ad5371 81 */
Sissors 0:f8c1b0ad5371 82 void pulsewidth_ms(int ms);
Sissors 0:f8c1b0ad5371 83
Sissors 0:f8c1b0ad5371 84 /**
Sissors 0:f8c1b0ad5371 85 * Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same.
Sissors 0:f8c1b0ad5371 86 */
Sissors 0:f8c1b0ad5371 87 void pulsewidth_us(int us);
Sissors 0:f8c1b0ad5371 88
Sissors 0:f8c1b0ad5371 89 /**
Sissors 0:f8c1b0ad5371 90 * Set the PWM pulsewidth, specified in micro-seconds (double), keeping the period the same.
Sissors 0:f8c1b0ad5371 91 */
Sissors 0:f8c1b0ad5371 92 void pulsewidth_us(double us);
Sissors 0:f8c1b0ad5371 93
Sissors 0:f8c1b0ad5371 94 /**
Sissors 4:a7b9f778c4b4 95 * Set the PWM period, specified in clock ticks, keeping the period the same.
Sissors 4:a7b9f778c4b4 96 *
Sissors 4:a7b9f778c4b4 97 * This function can be used if low overhead is required. Do take into account the result is
Sissors 4:a7b9f778c4b4 98 * board (clock frequency) dependent!
Sissors 4:a7b9f778c4b4 99 */
Sissors 4:a7b9f778c4b4 100 void pulsewidth_ticks(uint32_t ticks);
Sissors 4:a7b9f778c4b4 101
Sissors 4:a7b9f778c4b4 102 /**
Sissors 0:f8c1b0ad5371 103 * Set the ouput duty-cycle, specified as a percentage (double)
Sissors 0:f8c1b0ad5371 104 *
Sissors 0:f8c1b0ad5371 105 * @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 106 */
Sissors 0:f8c1b0ad5371 107 void write(double duty);
pmic 37:0ca2cf9a1437 108 void write(float duty);
Sissors 0:f8c1b0ad5371 109
Sissors 0:f8c1b0ad5371 110 /**
Sissors 0:f8c1b0ad5371 111 * Return the ouput duty-cycle, specified as a percentage (double)
Sissors 0:f8c1b0ad5371 112 *
Sissors 0:f8c1b0ad5371 113 * @param return - A double value representing the output duty-cycle, specified as a percentage.
Sissors 0:f8c1b0ad5371 114 */
Sissors 0:f8c1b0ad5371 115 double read( void );
Sissors 0:f8c1b0ad5371 116
Sissors 0:f8c1b0ad5371 117 /**
Sissors 0:f8c1b0ad5371 118 * An operator shorthand for write()
Sissors 0:f8c1b0ad5371 119 */
Sissors 0:f8c1b0ad5371 120 FastPWM& operator= (double value);
Sissors 0:f8c1b0ad5371 121
Sissors 0:f8c1b0ad5371 122 /**
Sissors 0:f8c1b0ad5371 123 * An operator shorthand for read()
Sissors 0:f8c1b0ad5371 124 */
Sissors 0:f8c1b0ad5371 125 operator double();
Sissors 0:f8c1b0ad5371 126
Sissors 4:a7b9f778c4b4 127 /**
Sissors 4:a7b9f778c4b4 128 * Set the PWM prescaler
Sissors 4:a7b9f778c4b4 129 *
Sissors 4:a7b9f778c4b4 130 * The period of all PWM pins on the same PWM unit have to be reset after using this!
Sissors 4:a7b9f778c4b4 131 *
Sissors 4:a7b9f778c4b4 132 * @param value - The required prescaler. Special values: 0 = lock current prescaler, -1 = use dynamic prescaler
Sissors 4:a7b9f778c4b4 133 * @param return - The prescaler which was set (can differ from requested prescaler if not possible)
Sissors 4:a7b9f778c4b4 134 */
Sissors 4:a7b9f778c4b4 135 int prescaler(int value);
Sissors 4:a7b9f778c4b4 136
Sissors 0:f8c1b0ad5371 137 private:
Sissors 4:a7b9f778c4b4 138 void initFastPWM(void);
Sissors 4:a7b9f778c4b4 139
Sissors 4:a7b9f778c4b4 140 uint32_t setPrescaler( uint32_t reqScale );
Sissors 4:a7b9f778c4b4 141 int calcPrescaler(uint64_t clocks);
Sissors 4:a7b9f778c4b4 142 uint32_t getPeriod( void );
Sissors 4:a7b9f778c4b4 143
Sissors 4:a7b9f778c4b4 144 void updateTicks( uint32_t prescaler );
Sissors 4:a7b9f778c4b4 145 uint32_t bits;
Sissors 4:a7b9f778c4b4 146
Sissors 0:f8c1b0ad5371 147 double _duty;
Sissors 0:f8c1b0ad5371 148
Sissors 4:a7b9f778c4b4 149 double dticks, dticks_us;
Sissors 4:a7b9f778c4b4 150 int iticks_ms, iticks_us;
Sissors 4:a7b9f778c4b4 151
Sissors 4:a7b9f778c4b4 152 bool dynamicPrescaler;
Sissors 4:a7b9f778c4b4 153
Sissors 12:4600daab8a83 154 void *fast_obj;
Sissors 0:f8c1b0ad5371 155 };
Sissors 0:f8c1b0ad5371 156 #endif