CommandStation-EX/DCCTimerGiga.cpp

/*
 *  @ 2023 Travis Farmer
 *  © 2023 Neil McKechnie
 *  © 2022-2023 Paul M. Antoine
 *  © 2021 Mike S
 *  © 2021, 2023 Harald Barth
 *  © 2021 Fred Decker
 *  © 2021 Chris Harlow
 *  © 2021 David Cutting
 *  All rights reserved.
 *  
 *  This file is part of Asbelos DCC API
 *
 *  This is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  It is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
 */

// ATTENTION: this file only compiles on a STM32 based boards
// Please refer to DCCTimer.h for general comments about how this class works
// This is to avoid repetition and duplication.
#ifdef ARDUINO_GIGA

#include "DCCTimer.h"
#ifdef DEBUG_ADC
#include "TrackManager.h"
#endif
#include "DIAG.h"

///////////////////////////////////////////////////////////////////////////////////////////////
// Experimental code for High Accuracy (HA) DCC Signal mode
// Warning - use of TIM2 and TIM3 can affect the use of analogWrite() function on certain pins,
// which is used by the DC motor types.
///////////////////////////////////////////////////////////////////////////////////////////////

/*INTERRUPT_CALLBACK interruptHandler=0;
// // Let's use STM32's timer #2 which supports hardware pulse generation on pin D13.
// // Also, timer #3 will do hardware pulses on pin D12. This gives
// // accurate timing, independent of the latency of interrupt handling.
// // We only need to interrupt on one of these (TIM2), the other will just generate
// // pulses.
 HardwareTimer timer(TIM1);
 HardwareTimer timerAux(TIM3);
 static bool tim2ModeHA = false;
 static bool tim3ModeHA = false;

 // Timer IRQ handler
 void Timer_Handler() {
   interruptHandler();
}

void DCCTimer::begin(INTERRUPT_CALLBACK callback) {
   interruptHandler=callback;
   noInterrupts();

   // adc_set_sample_rate(ADC_SAMPLETIME_480CYCLES);
   timer.pause();
   timerAux.pause();
   timer.setPrescaleFactor(1);
   timer.setOverflow(DCC_SIGNAL_TIME, MICROSEC_FORMAT);
   timer.attachInterrupt(Timer_Handler);
   timer.refresh();
   timerAux.setPrescaleFactor(1);
   timerAux.setOverflow(DCC_SIGNAL_TIME, MICROSEC_FORMAT);
   timerAux.refresh();
  
   timer.resume();
   timerAux.resume();

   interrupts();
}

bool DCCTimer::isPWMPin(byte pin) {
   // Timer 2 Channel 1 controls pin D13, and Timer3 Channel 1 controls D12.
   //  Enable the appropriate timer channel.
   switch (pin) {
     case 12:
       return true;
     case 13:
       return true;
     default:
       return false;
   }
}

void DCCTimer::setPWM(byte pin, bool high) {
   // Set the timer so that, at the next counter overflow, the requested
   // pin state is activated automatically before the interrupt code runs.
   // TIM2 is timer, TIM3 is timerAux.
   switch (pin) {
     case 12:
       if (!tim3ModeHA) {
         timerAux.setMode(1, TIMER_OUTPUT_COMPARE_INACTIVE, D12);
         tim3ModeHA = true;
       }
       if (high) 
         TIM3->CCMR1 = (TIM3->CCMR1 & ~TIM_CCMR1_OC1M_Msk) | TIM_CCMR1_OC1M_0;
       else
         TIM3->CCMR1 = (TIM3->CCMR1 & ~TIM_CCMR1_OC1M_Msk) | TIM_CCMR1_OC1M_1;
       break;
     case 13:
       if (!tim2ModeHA) {
         timer.setMode(1, TIMER_OUTPUT_COMPARE_INACTIVE, D13);
         tim2ModeHA = true;
       }
       if (high) 
         TIM2->CCMR1 = (TIM2->CCMR1 & ~TIM_CCMR1_OC1M_Msk) | TIM_CCMR1_OC1M_0;
       else
         TIM2->CCMR1 = (TIM2->CCMR1 & ~TIM_CCMR1_OC1M_Msk) | TIM_CCMR1_OC1M_1;
       break;
   }   
}

 void DCCTimer::clearPWM() {
   timer.setMode(1, TIMER_OUTPUT_COMPARE_INACTIVE, NC);
   tim2ModeHA = false;
   timerAux.setMode(1, TIMER_OUTPUT_COMPARE_INACTIVE, NC);  
   tim3ModeHA = false;
}*/
///////////////////////////////////////////////////////////////////////////////////////////////
INTERRUPT_CALLBACK interruptHandler=0;
extern char *__brkval;
extern char *__malloc_heap_start;

  
  void DCCTimer::begin(INTERRUPT_CALLBACK callback) {
    interruptHandler=callback;
    noInterrupts(); 
    ADC0.CTRLC = (ADC0.CTRLC & 0b00110000) | 0b01000011;  // speed up analogRead sample time   
    TCB0.CTRLB = TCB_CNTMODE_INT_gc & ~TCB_CCMPEN_bm; // timer compare mode with output disabled
    TCB0.CTRLA = TCB_CLKSEL_CLKDIV2_gc; //   8 MHz ~ 0.125 us      
    TCB0.CCMP =  CLOCK_CYCLES -1;  // 1 tick less for timer reset
    TCB0.INTFLAGS = TCB_CAPT_bm; // clear interrupt request flag
    TCB0.INTCTRL = TCB_CAPT_bm;  // Enable the interrupt
    TCB0.CNT = 0;
    TCB0.CTRLA |= TCB_ENABLE_bm;  // start
    interrupts();
  }

  // ISR called by timer interrupt every 58uS
  ISR(TCB0_INT_vect){
    TCB0.INTFLAGS = TCB_CAPT_bm; // Clear interrupt request flag
    interruptHandler();
  }

  bool DCCTimer::isPWMPin(byte pin) {
       (void) pin; 
       return false;  // TODO what are the relevant pins? 
  }

 void DCCTimer::setPWM(byte pin, bool high) {
    (void) pin;
    (void) high;
    // TODO what are the relevant pins?
 }

void DCCTimer::clearPWM() {
    // Do nothing unless we implent HA
}

  void   DCCTimer::getSimulatedMacAddress(byte mac[6]) {
    memcpy(mac,(void *) &SIGROW.SERNUM0,6);  // serial number
    mac[0] &= 0xFE;
    mac[0] |= 0x02;
  }

volatile int DCCTimer::minimum_free_memory=__INT_MAX__;

// Return low memory value... 
int DCCTimer::getMinimumFreeMemory() {
  noInterrupts(); // Disable interrupts to get volatile value 
  int retval = minimum_free_memory;
  interrupts();
  return retval;
}

extern char *__brkval;
extern char *__malloc_heap_start;

int DCCTimer::freeMemory() {
  char top;
  return __brkval ? &top - __brkval : &top - __malloc_heap_start;
}

void DCCTimer::reset() {
  CPU_CCP=0xD8;
  WDT.CTRLA=0x4;
  while(true){}
}

int16_t ADCee::ADCmax()
{
    return 4095;
}

int ADCee::init(uint8_t pin) {
  return analogRead(pin);
}

/*
 * Read function ADCee::read(pin) to get value instead of analogRead(pin)
 */
int ADCee::read(uint8_t pin, bool fromISR) {
  int current;
  if (!fromISR) noInterrupts();
  current = analogRead(pin);
  if (!fromISR) interrupts();
  return current;
}

/*
 * Scan function that is called from interrupt
 */
#pragma GCC push_options
#pragma GCC optimize ("-O3")
void ADCee::scan() {
}
#pragma GCC pop_options

void ADCee::begin() {
  noInterrupts();
  interrupts();
}
#endif