Diff: FastPWM.h

Revision:

0:f8c1b0ad5371

Child:

1:1aed61747ed6

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FastPWM.h	Thu Jul 12 11:20:09 2012 +0000
@@ -0,0 +1,105 @@
+#include "mbed.h"
+
+
+#ifndef FASTPWM_H
+#define FASTPWM_H
+
+#ifndef F_CLK
+#define F_CLK   96000000
+#endif
+
+/** Library that allows faster and/or higher resolution PWM output
+  *
+  * Library can directly replace standard mbed PWM library. Only limitation is that the maximum PWM period is four times shorter
+  * The maximum achievable period is roughly 40 seconds, I dont think that should be a problem.
+  * Do take into account all PWM objects will run four times faster than default.
+  *
+  * 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.
+  *
+  * In your program you can define F_CLK if you use a different clock frequency than the default one. 
+  *
+  * 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.
+  */
+class FastPWM {
+public:
+    /**
+    * Create a FastPWM object connected to the specified pin
+    *
+    * @param pin - PWM pin to connect to
+    */
+    FastPWM(PinName pin);
+    
+    /**
+    * Set the PWM period, specified in seconds (double), keeping the duty cycle the same.
+    */
+    void period(double seconds);
+    
+    /**
+    * Set the PWM period, specified in milli-seconds (int), keeping the duty cycle the same.
+    */
+    void period_ms(int ms);
+    
+    /**
+    * Set the PWM period, specified in micro-seconds (int), keeping the duty cycle the same.
+    */
+    void period_us(int us);
+    
+    /**
+    * Set the PWM period, specified in micro-seconds (double), keeping the duty cycle the same.
+    */
+    void period_us(double us);
+    
+    /**
+    * 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 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();
+    
+private:
+    PwmOut PWMObject;
+    double _duty;
+    double _period;
+    
+    __IO uint32_t *MR;
+
+};
+#endif
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