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Potmeter FastPWM.h
FastPWM.h
- Committer:
- vd
- Date:
- 2017-09-19
- Revision:
- 0:16be67f4d9ac
File content as of revision 0:16be67f4d9ac:
/* .---. _....._ / p `\ .-""`: :`"-. |__ - | ,' . ' ', ._> \ /: : ; :, '-. '\`. . : ' \ `. | .'._.' '._.' '._.'. | `;-\. : : ' '/,__, .-'`'._ ' . : _.'.__.' ((((-'/ `";--..:..--;"` \ .' / \ \ jgs ((((-' ((((-' Yeah ASCII art turtle more fun than copyright stuff */ #include "mbed.h" #ifndef FASTPWM_H #define FASTPWM_H /** Library that allows faster and/or higher resolution PWM output * * Library can directly replace standard mbed PWM library. * * Contrary to the default mbed library, this library takes doubles instead of floats. The compiler will autocast if needed, * but do take into account it is done for a reason, your accuracy will otherwise be limitted by the floating point precision. */ class FastPWM : public PwmOut { public: /** * Create a FastPWM object connected to the specified pin * * @param pin - PWM pin to connect to * @param prescaler - Clock prescaler, -1 is dynamic (default), 0 is bit random, everything else normal */ FastPWM(PinName pin, int prescaler = -1); ~FastPWM(); /** * Set the PWM period, specified in seconds (double), keeping the pulsewidth the same. */ void period(double seconds); /** * Set the PWM period, specified in milli-seconds (int), keeping the pulsewidth the same. */ void period_ms(int ms); /** * Set the PWM period, specified in micro-seconds (int), keeping the pulsewidth the same. */ void period_us(int us); /** * Set the PWM period, specified in micro-seconds (double), keeping the pulsewidth the same. */ void period_us(double us); /** * Set the PWM period, specified in clock ticks, keeping _pulse width_ the same. * * This function can be used if low overhead is required. Do take into account the result is * board (clock frequency) dependent, and this does not keep an equal duty cycle! */ void period_ticks(uint32_t ticks); /** * Set the PWM pulsewidth, specified in seconds (double), keeping the period the same. */ void pulsewidth(double seconds); /** * Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same. */ void pulsewidth_ms(int ms); /** * Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same. */ void pulsewidth_us(int us); /** * Set the PWM pulsewidth, specified in micro-seconds (double), keeping the period the same. */ void pulsewidth_us(double us); /** * Set the PWM period, specified in clock ticks, keeping the period the same. * * This function can be used if low overhead is required. Do take into account the result is * board (clock frequency) dependent! */ void pulsewidth_ticks(uint32_t ticks); /** * Set the ouput duty-cycle, specified as a percentage (double) * * @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%). */ void write(double duty); /** * Return the ouput duty-cycle, specified as a percentage (double) * * @param return - A double value representing the output duty-cycle, specified as a percentage. */ double read( void ); /** * An operator shorthand for write() */ FastPWM& operator= (double value); /** * An operator shorthand for read() */ operator double(); /** * Set the PWM prescaler * * The period of all PWM pins on the same PWM unit have to be reset after using this! * * @param value - The required prescaler. Special values: 0 = lock current prescaler, -1 = use dynamic prescaler * @param return - The prescaler which was set (can differ from requested prescaler if not possible) */ int prescaler(int value); private: void initFastPWM(void); uint32_t setPrescaler( uint32_t reqScale ); int calcPrescaler(uint64_t clocks); uint32_t getPeriod( void ); void updateTicks( uint32_t prescaler ); uint32_t bits; double _duty; double dticks, dticks_us; int iticks_ms, iticks_us; bool dynamicPrescaler; void *fast_obj; }; #endif