src/lib/HWTIMER/STM32_hwTimer.cpp

   1 #ifdef PLATFORM_STM32
   2 #include "STM32_hwTimer.h"
   3
   4 void inline hwTimer::nullCallback(void) {}
   5
   6 void (*hwTimer::callbackTick)() = &nullCallback;
   7 void (*hwTimer::callbackTock)() = &nullCallback;
   8
   9 volatile uint32_t hwTimer::HWtimerInterval = TimerIntervalUSDefault;
  10 volatile bool hwTimer::isTick = false;
  11 volatile int32_t hwTimer::PhaseShift = 0;
  12 volatile int32_t hwTimer::FreqOffset = 0;
  13 volatile uint32_t hwTimer::PauseDuration = 0;
  14 bool hwTimer::running = false;
  15 bool hwTimer::alreadyInit = false;
  16
  17 #if defined(TIM1)
  18 HardwareTimer(*hwTimer::MyTim) = new HardwareTimer(TIM1);
  19 #else
  20 // FM30_mini (STM32F373xC) no advanced timer but TIM2 is 32-bit general purpose
  21 HardwareTimer(*hwTimer::MyTim) = new HardwareTimer(TIM2);
  22 #endif
  23
  24 void hwTimer::init()
  25 {
  26     if (!alreadyInit)
  27     {
  28         MyTim->attachInterrupt(hwTimer::callback);
  29         MyTim->setMode(1, TIMER_OUTPUT_COMPARE);
  30 #if defined(TARGET_TX)
  31         // The prescaler only adjusts AFTER the overflow interrupt fires so
  32         // to make Pause() work, the prescaler needs to be fixed to avoid
  33         // having to ramp between prescalers
  34         MyTim->setPrescaleFactor(MyTim->getTimerClkFreq() / 1000000); // 1us per tick
  35         MyTim->setOverflow(hwTimer::HWtimerInterval >> 1, TICK_FORMAT);
  36 #else
  37         MyTim->setOverflow(hwTimer::HWtimerInterval >> 1, MICROSEC_FORMAT); // 22(50Hz) to 3(500Hz) scaler
  38 #endif
  39         MyTim->setPreloadEnable(false);
  40         alreadyInit = true;
  41     }
  42 }
  43
  44 void hwTimer::stop()
  45 {
  46     running = false;
  47     MyTim->pause();
  48     MyTim->setCount(0);
  49 }
  50
  51 /*
  52  * Schedule a pause of the specified duration, in us -- TX Only
  53  * Will pause until the TICK interrupt, then the next timer will
  54  * fire Duration - interval/2 after that
  55  * 65535us max!
  56  */
  57 void hwTimer::pause(uint32_t duration)
  58 {
  59 #if defined(TARGET_TX)
  60     PauseDuration = duration;
  61     while(PauseDuration);
  62 #endif
  63 }
  64
  65 void hwTimer::resume()
  66 {
  67     isTick = false;
  68     running = true;
  69     #if defined(TARGET_TX)
  70     MyTim->setOverflow(hwTimer::HWtimerInterval >> 1, TICK_FORMAT);
  71     #else
  72     MyTim->setOverflow((hwTimer::HWtimerInterval >> 1), MICROSEC_FORMAT);
  73     #endif
  74     MyTim->setCount(0);
  75     MyTim->resume();
  76     MyTim->refresh(); // will trigger the interrupt immediately, but will update the prescaler shadow reg
  77 }
  78
  79 void hwTimer::updateInterval(uint32_t newTimerInterval)
  80 {
  81     // timer should not be running when updateInterval() is called
  82     hwTimer::HWtimerInterval = newTimerInterval;
  83 }
  84
  85 void hwTimer::resetFreqOffset()
  86 {
  87     FreqOffset = 0;
  88 }
  89
  90 void hwTimer::incFreqOffset()
  91 {
  92     FreqOffset++;
  93 }
  94
  95 void hwTimer::decFreqOffset()
  96 {
  97     FreqOffset--;
  98 }
  99
 100 void hwTimer::phaseShift(int32_t newPhaseShift)
 101 {
 102     int32_t minVal = -(hwTimer::HWtimerInterval >> 2);
 103     int32_t maxVal = (hwTimer::HWtimerInterval >> 2);
 104     hwTimer::PhaseShift = constrain(newPhaseShift, minVal, maxVal);
 105 }
 106
 107 void hwTimer::callback(void)
 108 {
 109     if (hwTimer::isTick)
 110     {
 111 #if defined(TARGET_TX)
 112         if (PauseDuration)
 113         {
 114             MyTim->setOverflow(PauseDuration - (hwTimer::HWtimerInterval >> 1), TICK_FORMAT);
 115             PauseDuration = 0;
 116             // No tick callback
 117         }
 118         else
 119         {
 120             MyTim->setOverflow(hwTimer::HWtimerInterval >> 1, TICK_FORMAT);
 121             hwTimer::callbackTick();
 122         }
 123 #else
 124         MyTim->setOverflow((hwTimer::HWtimerInterval >> 1), MICROSEC_FORMAT);
 125         uint32_t adjustedInterval = MyTim->getOverflow(TICK_FORMAT) + FreqOffset;
 126         MyTim->setOverflow(adjustedInterval, TICK_FORMAT);
 127         hwTimer::callbackTick();
 128 #endif
 129     }
 130     else
 131     {
 132 #if defined(TARGET_TX)
 133         MyTim->setOverflow(hwTimer::HWtimerInterval >> 1, TICK_FORMAT);
 134         hwTimer::callbackTock();
 135 #else
 136         MyTim->setOverflow((hwTimer::HWtimerInterval >> 1) + hwTimer::PhaseShift, MICROSEC_FORMAT);
 137         uint32_t adjustedInterval = MyTim->getOverflow(TICK_FORMAT) + FreqOffset;
 138         MyTim->setOverflow(adjustedInterval, TICK_FORMAT);
 139         hwTimer::PhaseShift = 0;
 140         hwTimer::callbackTock();
 141 #endif
 142     }
 143     hwTimer::isTick = !hwTimer::isTick;
 144 }
 145 #endif