Dmitry Shalnoff's Git Repository - ETG_Helmet/blob - SOFTWARE/UTILS/fast-gpio/src/fastpwm.cpp

   1 #include <fastpwm.h>
   2
   3 FastPwm::FastPwm(void)
   4 {
   5         Reset();
   6         if (strcmp(DEVICE_TYPE, "ramips") == 0) {
   7                 gpio = new FastGpioOmega2();
   8         } else {
   9                 gpio = new FastGpioOmega();
  10         }
  11 }
  12
  13 FastPwm::FastPwm(int freq, int duty, unsigned int cycles)
  14 {
  15         Reset();
  16
  17         // setup the pwm info
  18         _SetupPeriods(freq, duty, cycles);
  19
  20         //Instantiate the GPIO object
  21                 // object setup
  22         if (strcmp(DEVICE_TYPE, "ramips") == 0) {
  23                 gpio = new FastGpioOmega2();
  24         } else {
  25                 gpio = new FastGpioOmega();
  26         }
  27 }
  28
  29 FastPwm::~FastPwm(void)
  30 {
  31         // nothing for now
  32 }
  33
  34 void FastPwm::Reset(void)
  35 {
  36         bSetup  = 0;
  37 }
  38
  39
  40 void FastPwm::_SetupPeriods(int frequency, int duty, unsigned int cycles)
  41 {
  42         double  dutyCycleInv;
  43
  44         // convert the datatypes
  45         freq            = (double) frequency;
  46         dutyCycle       = (double)duty / 100.0f;
  47
  48         // find the period (in ms)
  49         period          = (1.0f/freq) * 10000; // 1000
  50
  51         // find the low and high periods based on the duty-cycle
  52         periodHigh      = period * dutyCycle;
  53         periodLow       = period - periodHigh; //can also be: period * (1.0f - dutyCycle);
  54
  55         if ( cycles != 0 ) myCycles     = cycles; else myCycles = 0;
  56
  57         // note that setup has occured
  58         bSetup = 1;
  59
  60         if (verbosityLevel > 0) {
  61                 printf (        "PWM Setup:: frequency = %d, duty-cycle = %d%%\nperiod = %.2f, period hi = %.2f, period lo = %.2f\n",
  62                                         frequency,
  63                                         duty,
  64                                         period,
  65                                         periodHigh,
  66                                         periodLow
  67                                 );
  68         }
  69 }
  70
  71 void FastPwm::Pwm (int pinNum)
  72 {
  73         if (bSetup == 0) {
  74                 _SetupPeriods(DEFAULT_FREQ, DEFAULT_DUTY_CYCLE, 0);
  75         }
  76
  77         // run the pwm
  78         _Pwm(pinNum);
  79 }
  80
  81 void FastPwm::Pwm (int pinNum, int freq, int duty, unsigned int cycles)
  82 {
  83         _SetupPeriods(freq, duty, cycles);
  84
  85         // run the pwm
  86         _Pwm(pinNum);
  87 }
  88
  89 void FastPwm::_Pwm (int pinNum)
  90 {
  91         // set the pin to output
  92         gpio->SetDirection(pinNum, 1);
  93
  94         // start the loop
  95         while (1) {
  96
  97                 if ( myCycles != 0 ) myCycles --;
  98                 if ( myCycles == 1 ) break;
  99
 100                 //// HIGH part of cycle
 101                 gpio->Set(pinNum, 1);
 102                 _Sleep(periodHigh);
 103
 104                 // LOW part of cycle
 105                 gpio->Set(pinNum, 0);
 106                 _Sleep(periodLow);
 107         }
 108 }
 109
 110 void FastPwm::_Sleep (double length)
 111 {
 112         // sleep function uses microseconds
 113         int value       = (int)(length * 1000);
 114
 115         usleep(value);
 116 }