Geofrey Marcel / FastPWM

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

Fork of FastPWM by Erik -

FastPWM.h@0:f8c1b0ad5371, 2012-07-12 (annotated)

Committer:
Sissors
Date:
Thu Jul 12 11:20:09 2012 +0000
Revision:
0:f8c1b0ad5371
Child:
1:1aed61747ed6
v1.0, seems completely functional

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Sissors 0:f8c1b0ad5371 1 #include "mbed.h"
Sissors 0:f8c1b0ad5371 2
Sissors 0:f8c1b0ad5371 3
Sissors 0:f8c1b0ad5371 4 #ifndef FASTPWM_H
Sissors 0:f8c1b0ad5371 5 #define FASTPWM_H
Sissors 0:f8c1b0ad5371 6
Sissors 0:f8c1b0ad5371 7 #ifndef F_CLK
Sissors 0:f8c1b0ad5371 8 #define F_CLK 96000000
Sissors 0:f8c1b0ad5371 9 #endif
Sissors 0:f8c1b0ad5371 10
Sissors 0:f8c1b0ad5371 11 /** Library that allows faster and/or higher resolution PWM output
Sissors 0:f8c1b0ad5371 12 *
Sissors 0:f8c1b0ad5371 13 * Library can directly replace standard mbed PWM library. Only limitation is that the maximum PWM period is four times shorter
Sissors 0:f8c1b0ad5371 14 * The maximum achievable period is roughly 40 seconds, I dont think that should be a problem.
Sissors 0:f8c1b0ad5371 15 * Do take into account all PWM objects will run four times faster than default.
Sissors 0:f8c1b0ad5371 16 *
Sissors 0:f8c1b0ad5371 17 * Contrary to the default mbed library, this library takes doubles instead of floats. The compiler will autocast if needed,
Sissors 0:f8c1b0ad5371 18 * 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 19 *
Sissors 0:f8c1b0ad5371 20 * In your program you can define F_CLK if you use a different clock frequency than the default one.
Sissors 0:f8c1b0ad5371 21 *
Sissors 0:f8c1b0ad5371 22 * Only works on LPC1768 for now. If you want support for the other one, send a PM and I will have a look, but I cannot even compile for it.
Sissors 0:f8c1b0ad5371 23 */
Sissors 0:f8c1b0ad5371 24 class FastPWM {
Sissors 0:f8c1b0ad5371 25 public:
Sissors 0:f8c1b0ad5371 26 /**
Sissors 0:f8c1b0ad5371 27 * Create a FastPWM object connected to the specified pin
Sissors 0:f8c1b0ad5371 28 *
Sissors 0:f8c1b0ad5371 29 * @param pin - PWM pin to connect to
Sissors 0:f8c1b0ad5371 30 */
Sissors 0:f8c1b0ad5371 31 FastPWM(PinName pin);
Sissors 0:f8c1b0ad5371 32
Sissors 0:f8c1b0ad5371 33 /**
Sissors 0:f8c1b0ad5371 34 * Set the PWM period, specified in seconds (double), keeping the duty cycle the same.
Sissors 0:f8c1b0ad5371 35 */
Sissors 0:f8c1b0ad5371 36 void period(double seconds);
Sissors 0:f8c1b0ad5371 37
Sissors 0:f8c1b0ad5371 38 /**
Sissors 0:f8c1b0ad5371 39 * Set the PWM period, specified in milli-seconds (int), keeping the duty cycle the same.
Sissors 0:f8c1b0ad5371 40 */
Sissors 0:f8c1b0ad5371 41 void period_ms(int ms);
Sissors 0:f8c1b0ad5371 42
Sissors 0:f8c1b0ad5371 43 /**
Sissors 0:f8c1b0ad5371 44 * Set the PWM period, specified in micro-seconds (int), keeping the duty cycle the same.
Sissors 0:f8c1b0ad5371 45 */
Sissors 0:f8c1b0ad5371 46 void period_us(int us);
Sissors 0:f8c1b0ad5371 47
Sissors 0:f8c1b0ad5371 48 /**
Sissors 0:f8c1b0ad5371 49 * Set the PWM period, specified in micro-seconds (double), keeping the duty cycle the same.
Sissors 0:f8c1b0ad5371 50 */
Sissors 0:f8c1b0ad5371 51 void period_us(double us);
Sissors 0:f8c1b0ad5371 52
Sissors 0:f8c1b0ad5371 53 /**
Sissors 0:f8c1b0ad5371 54 * Set the PWM pulsewidth, specified in seconds (double), keeping the period the same.
Sissors 0:f8c1b0ad5371 55 */
Sissors 0:f8c1b0ad5371 56 void pulsewidth(double seconds);
Sissors 0:f8c1b0ad5371 57
Sissors 0:f8c1b0ad5371 58 /**
Sissors 0:f8c1b0ad5371 59 * Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same.
Sissors 0:f8c1b0ad5371 60 */
Sissors 0:f8c1b0ad5371 61 void pulsewidth_ms(int ms);
Sissors 0:f8c1b0ad5371 62
Sissors 0:f8c1b0ad5371 63 /**
Sissors 0:f8c1b0ad5371 64 * Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same.
Sissors 0:f8c1b0ad5371 65 */
Sissors 0:f8c1b0ad5371 66 void pulsewidth_us(int us);
Sissors 0:f8c1b0ad5371 67
Sissors 0:f8c1b0ad5371 68 /**
Sissors 0:f8c1b0ad5371 69 * Set the PWM pulsewidth, specified in micro-seconds (double), keeping the period the same.
Sissors 0:f8c1b0ad5371 70 */
Sissors 0:f8c1b0ad5371 71 void pulsewidth_us(double us);
Sissors 0:f8c1b0ad5371 72
Sissors 0:f8c1b0ad5371 73 /**
Sissors 0:f8c1b0ad5371 74 * Set the ouput duty-cycle, specified as a percentage (double)
Sissors 0:f8c1b0ad5371 75 *
Sissors 0:f8c1b0ad5371 76 * @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 77 */
Sissors 0:f8c1b0ad5371 78 void write(double duty);
Sissors 0:f8c1b0ad5371 79
Sissors 0:f8c1b0ad5371 80 /**
Sissors 0:f8c1b0ad5371 81 * Return the ouput duty-cycle, specified as a percentage (double)
Sissors 0:f8c1b0ad5371 82 *
Sissors 0:f8c1b0ad5371 83 * @param return - A double value representing the output duty-cycle, specified as a percentage.
Sissors 0:f8c1b0ad5371 84 */
Sissors 0:f8c1b0ad5371 85 double read( void );
Sissors 0:f8c1b0ad5371 86
Sissors 0:f8c1b0ad5371 87 /**
Sissors 0:f8c1b0ad5371 88 * An operator shorthand for write()
Sissors 0:f8c1b0ad5371 89 */
Sissors 0:f8c1b0ad5371 90 FastPWM& operator= (double value);
Sissors 0:f8c1b0ad5371 91
Sissors 0:f8c1b0ad5371 92 /**
Sissors 0:f8c1b0ad5371 93 * An operator shorthand for read()
Sissors 0:f8c1b0ad5371 94 */
Sissors 0:f8c1b0ad5371 95 operator double();
Sissors 0:f8c1b0ad5371 96
Sissors 0:f8c1b0ad5371 97 private:
Sissors 0:f8c1b0ad5371 98 PwmOut PWMObject;
Sissors 0:f8c1b0ad5371 99 double _duty;
Sissors 0:f8c1b0ad5371 100 double _period;
Sissors 0:f8c1b0ad5371 101
Sissors 0:f8c1b0ad5371 102 __IO uint32_t *MR;
Sissors 0:f8c1b0ad5371 103
Sissors 0:f8c1b0ad5371 104 };
Sissors 0:f8c1b0ad5371 105 #endif