Giles Barton-Owen / PWMAverage

A PWM/duty cycle measurement library using Timer2

Dependents:   PWMAverage_test pwm_duty_measurement

PWMAverage.cpp@1:34a9269390d9, 2012-08-29 (annotated)

Committer:
p07gbar
Date:
Wed Aug 29 11:44:01 2012 +0000
Revision:
1:34a9269390d9
Parent:
0:5da51898a166 
Tidied the documentation, wrote a basic example

Who changed what in which revision?

UserRevisionLine numberNew contents of line
p07gbar 0:5da51898a166 1 #include "PWMAverage.h"
p07gbar 0:5da51898a166 2
p07gbar 0:5da51898a166 3 #define PWMA_PCLK 96000000
p07gbar 0:5da51898a166 4
p07gbar 0:5da51898a166 5
p07gbar 0:5da51898a166 6 PWMAverage * PWMAverage::instance;
p07gbar 0:5da51898a166 7
p07gbar 0:5da51898a166 8
p07gbar 0:5da51898a166 9 void PWMAverage::_tisr()
p07gbar 0:5da51898a166 10 {
p07gbar 0:5da51898a166 11 //printf(".");
p07gbar 0:5da51898a166 12 int cr0 = LPC_TIM2->CR0;
p07gbar 0:5da51898a166 13 int cr1 = LPC_TIM2->CR1;
p07gbar 0:5da51898a166 14
p07gbar 0:5da51898a166 15 LPC_TIM2->IR = 0x3F;
p07gbar 0:5da51898a166 16
p07gbar 0:5da51898a166 17 LPC_TIM2->TCR = 3;
p07gbar 0:5da51898a166 18 LPC_TIM2->TCR = 1;
p07gbar 0:5da51898a166 19
p07gbar 0:5da51898a166 20 //LPC_NVIC->ICPR0 |= (1<<3)
p07gbar 0:5da51898a166 21
p07gbar 0:5da51898a166 22 if(!instance->starting)
p07gbar 0:5da51898a166 23 {
p07gbar 0:5da51898a166 24 instance->total += cr1 + 82;
p07gbar 0:5da51898a166 25 instance->totalup += cr0 + 82;
p07gbar 0:5da51898a166 26 instance->count_++;
p07gbar 0:5da51898a166 27 }
p07gbar 0:5da51898a166 28 else instance->starting = false;
p07gbar 0:5da51898a166 29
p07gbar 0:5da51898a166 30 }
p07gbar 0:5da51898a166 31
p07gbar 0:5da51898a166 32 PWMAverage::PWMAverage(PinName cap0, PinName cap1)
p07gbar 0:5da51898a166 33 {
p07gbar 0:5da51898a166 34 prescaler_point = 0x0;
p07gbar 0:5da51898a166 35 configure();
p07gbar 0:5da51898a166 36 stop();
p07gbar 0:5da51898a166 37
p07gbar 0:5da51898a166 38 timeMult = (1/PWMA_PCLK)*(prescaler_point+1);
p07gbar 0:5da51898a166 39 timeDiv = PWMA_PCLK/(prescaler_point+1);
p07gbar 0:5da51898a166 40 instance = this;
p07gbar 0:5da51898a166 41 }
p07gbar 0:5da51898a166 42
p07gbar 0:5da51898a166 43 void PWMAverage::reset()
p07gbar 0:5da51898a166 44 {
p07gbar 0:5da51898a166 45 count_ = 0;
p07gbar 0:5da51898a166 46 total = 0;
p07gbar 0:5da51898a166 47 totalup = 0;
p07gbar 0:5da51898a166 48 LPC_TIM2->TCR = 2;
p07gbar 0:5da51898a166 49 LPC_TIM2->TCR = 0;
p07gbar 0:5da51898a166 50 }
p07gbar 0:5da51898a166 51
p07gbar 0:5da51898a166 52 void PWMAverage::start()
p07gbar 0:5da51898a166 53 {
p07gbar 0:5da51898a166 54 //reset();
p07gbar 0:5da51898a166 55 starting = true;
p07gbar 0:5da51898a166 56 enable(true);
p07gbar 0:5da51898a166 57 NVIC_EnableIRQ(TIMER2_IRQn);
p07gbar 0:5da51898a166 58 }
p07gbar 0:5da51898a166 59
p07gbar 0:5da51898a166 60 void PWMAverage::stop()
p07gbar 0:5da51898a166 61 {
p07gbar 0:5da51898a166 62 enable(false);
p07gbar 0:5da51898a166 63 NVIC_DisableIRQ(TIMER2_IRQn);
p07gbar 0:5da51898a166 64 }
p07gbar 0:5da51898a166 65
p07gbar 0:5da51898a166 66 float PWMAverage::read()
p07gbar 0:5da51898a166 67 {
p07gbar 0:5da51898a166 68 if(period() != 0) return float(avg_up()/period());
p07gbar 0:5da51898a166 69 else return 0;
p07gbar 0:5da51898a166 70 }
p07gbar 0:5da51898a166 71
p07gbar 0:5da51898a166 72 double PWMAverage::avg_up()
p07gbar 0:5da51898a166 73 {
p07gbar 0:5da51898a166 74 if(count_!= 0) return (double(totalup)/timeDiv)/double(count_);
p07gbar 0:5da51898a166 75 else return 0;
p07gbar 0:5da51898a166 76
p07gbar 0:5da51898a166 77 }
p07gbar 0:5da51898a166 78
p07gbar 0:5da51898a166 79 float PWMAverage::avg_UP()
p07gbar 0:5da51898a166 80 {
p07gbar 0:5da51898a166 81 if(count_!= 0) return float((double(totalup)/timeDiv)/double(count_));
p07gbar 0:5da51898a166 82 else return 0;
p07gbar 0:5da51898a166 83 }
p07gbar 0:5da51898a166 84
p07gbar 0:5da51898a166 85 double PWMAverage::avg_down()
p07gbar 0:5da51898a166 86 {
p07gbar 0:5da51898a166 87 if(count_!= 0) return (double(total-totalup)/timeDiv)/double(count_);
p07gbar 0:5da51898a166 88 else return 0;
p07gbar 0:5da51898a166 89 }
p07gbar 0:5da51898a166 90
p07gbar 0:5da51898a166 91 double PWMAverage::period()
p07gbar 0:5da51898a166 92 {
p07gbar 0:5da51898a166 93 if(count_!= 0) return (double(total)/timeDiv)/double(count_);
p07gbar 0:5da51898a166 94 else return 0;
p07gbar 0:5da51898a166 95 }
p07gbar 0:5da51898a166 96
p07gbar 0:5da51898a166 97 int PWMAverage::count()
p07gbar 0:5da51898a166 98 {
p07gbar 0:5da51898a166 99 return count_;
p07gbar 0:5da51898a166 100 }
p07gbar 0:5da51898a166 101
p07gbar 0:5da51898a166 102 void PWMAverage::enable(bool yn)
p07gbar 0:5da51898a166 103 {
p07gbar 0:5da51898a166 104 LPC_TIM2->TCR = yn;
p07gbar 0:5da51898a166 105 }
p07gbar 0:5da51898a166 106
p07gbar 0:5da51898a166 107 void PWMAverage::configure()
p07gbar 0:5da51898a166 108 {
p07gbar 0:5da51898a166 109 //Power Periferal
p07gbar 0:5da51898a166 110
p07gbar 0:5da51898a166 111 LPC_SC->PCONP |= (1<<22);
p07gbar 0:5da51898a166 112
p07gbar 0:5da51898a166 113 //Setup Pins
p07gbar 0:5da51898a166 114
p07gbar 0:5da51898a166 115 LPC_PINCON->PINSEL0 |= (0x3<<8);
p07gbar 0:5da51898a166 116 LPC_PINCON->PINSEL0 |= (0x3<<10);
p07gbar 0:5da51898a166 117
p07gbar 0:5da51898a166 118 //Setup clock source
p07gbar 0:5da51898a166 119
p07gbar 0:5da51898a166 120 LPC_SC->PCLKSEL1 |= (0x1<<12);
p07gbar 0:5da51898a166 121
p07gbar 0:5da51898a166 122 //Setup PC
p07gbar 0:5da51898a166 123
p07gbar 0:5da51898a166 124 LPC_TIM2->PR = prescaler_point;
p07gbar 0:5da51898a166 125
p07gbar 0:5da51898a166 126 //Setup CAP0 - Store on fall
p07gbar 0:5da51898a166 127
p07gbar 0:5da51898a166 128 LPC_TIM2->CCR |= 0x2;
p07gbar 0:5da51898a166 129
p07gbar 0:5da51898a166 130 //Setup CAP1 - Store on rise, interrupt
p07gbar 0:5da51898a166 131
p07gbar 0:5da51898a166 132 LPC_TIM2->CCR |= 0x5<<3;
p07gbar 0:5da51898a166 133
p07gbar 0:5da51898a166 134 //Setup IRQs
p07gbar 0:5da51898a166 135 NVIC_DisableIRQ(TIMER2_IRQn);
p07gbar 0:5da51898a166 136 NVIC_SetVector(TIMER2_IRQn, (uint32_t)&_tisr);
p07gbar 0:5da51898a166 137 NVIC_EnableIRQ(TIMER2_IRQn);
p07gbar 0:5da51898a166 138 //
p07gbar 0:5da51898a166 139 }