FastPWM_common.cpp

00001 #include "FastPWM.h"
00002 
00003 FastPWM::FastPWM(PinName pin, int prescaler) : PwmOut(pin) {
00004     fast_obj = NULL;
00005     initFastPWM();
00006     this->prescaler(prescaler);
00007     
00008     //Set duty cycle on 0%, period on 20ms
00009     period(0.02);
00010     write(0);
00011     
00012 
00013 }
00014 
00015 FastPWM::~FastPWM( void ) {
00016     if (fast_obj != NULL)
00017         free(fast_obj);
00018 } 
00019 
00020 void FastPWM::period(double seconds) {
00021     if (dynamicPrescaler)
00022         calcPrescaler((uint64_t)(seconds * (double) SystemCoreClock));
00023 
00024      period_ticks(seconds * dticks + 0.5);
00025 }
00026 
00027 void FastPWM::period_ms(int ms) {
00028     if (dynamicPrescaler)
00029         calcPrescaler(ms * (SystemCoreClock / 1000));
00030         
00031     period_ticks(ms * iticks_ms);
00032 }
00033 
00034 void FastPWM::period_us(int us) {
00035     if (dynamicPrescaler)
00036         calcPrescaler(us * (SystemCoreClock / 1000000));
00037     
00038     period_ticks(us * iticks_us);
00039 }
00040 
00041 void FastPWM::period_us(double us) {
00042     if (dynamicPrescaler)
00043         calcPrescaler((uint64_t)(us * (double)(SystemCoreClock / 1000000)));
00044         
00045     period_ticks(us * dticks_us + 0.5);
00046 }
00047 
00048 void FastPWM::pulsewidth(double seconds) {
00049     pulsewidth_ticks(seconds * dticks + 0.5);
00050 }
00051 
00052 void FastPWM::pulsewidth_ms(int ms) {
00053     pulsewidth_ticks(ms * iticks_ms);
00054 }
00055 
00056 void FastPWM::pulsewidth_us(int us) {
00057     pulsewidth_ticks(us * iticks_us);
00058 }
00059 
00060 void FastPWM::pulsewidth_us(double us) {
00061     pulsewidth_ticks(us * dticks_us + 0.5);
00062 }
00063 
00064 void FastPWM::write(double duty) {
00065     _duty=duty;
00066     pulsewidth_ticks(duty*getPeriod());
00067 }
00068 
00069 double FastPWM::read( void ) {
00070     return _duty;
00071     }
00072     
00073 FastPWM & FastPWM::operator= (double value) {
00074     write(value);
00075     return(*this);
00076     }
00077     
00078 FastPWM::operator double() {
00079     return _duty;
00080 }
00081 
00082 int FastPWM::prescaler(int value) {
00083     int retval;
00084     if (value == -1) {
00085         dynamicPrescaler = true;
00086         value = 0;
00087     }
00088     else
00089         dynamicPrescaler = false;
00090     
00091     retval = setPrescaler(value);
00092     updateTicks(retval);
00093     return retval;
00094 }
00095 
00096 void FastPWM::updateTicks( uint32_t prescaler ) {
00097     dticks = SystemCoreClock / (double)prescaler;
00098     dticks_us = dticks / 1000000.0f;
00099     iticks_us = (int)(dticks_us + 0.5);
00100     iticks_ms = (int)(dticks_us * 1000.0 + 0.5);
00101 }
00102 
00103 int FastPWM::calcPrescaler(uint64_t clocks) {
00104     uint32_t scale = (clocks >> bits) + 1;
00105     uint32_t retval = setPrescaler(scale);
00106     updateTicks(retval);
00107     return retval;
00108 }