Revision 0:f8c1b0ad5371, committed 2012-07-12

Comitter:

Sissors

Date:

Thu Jul 12 11:20:09 2012 +0000

Child:

1:1aed61747ed6

Commit message:

v1.0, seems completely functional

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FastPWM.cpp	Thu Jul 12 11:20:09 2012 +0000
@@ -0,0 +1,75 @@
+#include "FastPWM.h"
+
+FastPWM::FastPWM(PinName pin) : PWMObject(pin){
+    _duty=0;
+    _period=0.02;
+    if (pin==p26||pin==LED1)
+        MR=&LPC_PWM1->MR1;
+    else if (pin==p25||pin==LED2)
+        MR=&LPC_PWM1->MR2;
+    else if (pin==p24||pin==LED3)
+        MR=&LPC_PWM1->MR3;
+    else if (pin==p23||pin==LED4)
+        MR=&LPC_PWM1->MR4;
+    else if (pin==p22)
+        MR=&LPC_PWM1->MR5;
+    else if (pin==p21)
+        MR=&LPC_PWM1->MR6;
+    else
+        error("No hardware PWM pin\n\r");
+    
+    period(_period);
+}
+
+void FastPWM::period(double seconds) {
+    LPC_PWM1->MR0 = (unsigned int) (seconds * (double)F_CLK);
+    pulsewidth(_duty*seconds);
+    _period = seconds;
+}
+
+void FastPWM::period_ms(int ms) {
+    period((double)ms*1000.0);
+}
+
+void FastPWM::period_us(int us) {
+    period((double)us*1000000.0);
+}
+
+void FastPWM::period_us(double us) {
+    period(us*1000000.0);
+}
+
+void FastPWM::pulsewidth(double seconds) {
+    *MR=(unsigned int) (seconds * (double)F_CLK);
+}
+
+void FastPWM::pulsewidth_ms(int ms) {
+    pulsewidth((double)ms*1000.0);
+}
+
+void FastPWM::pulsewidth_us(int us) {
+    pulsewidth((double)us*1000000.0);
+}
+
+void FastPWM::pulsewidth_us(double us) {
+    pulsewidth(us*1000000.0);
+}
+
+void FastPWM::write(double duty) {
+    _duty=duty;
+    pulsewidth(duty*_period);
+}
+
+double FastPWM::read( void ) {
+    return _duty;
+    }
+    
+FastPWM & FastPWM::operator= (double value) {
+    write(value);
+    return(*this);
+    }
+    
+FastPWM::operator double() {
+    return _duty;
+}
+    
\ No newline at end of file

--- /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
\ No newline at end of file