mirror of
https://github.com/DCC-EX/CommandStation-EX.git
synced 2024-11-26 17:46:14 +01:00
315 lines
8.8 KiB
C++
315 lines
8.8 KiB
C++
/*
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* © 2021 Mike S
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* © 2021-2023 Harald Barth
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* © 2021 Fred Decker
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* © 2021 Chris Harlow
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* © 2021 David Cutting
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* All rights reserved.
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*
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* This file is part of Asbelos DCC API
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*
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* This is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* It is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with CommandStation. If not, see <https://www.gnu.org/licenses/>.
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*/
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// ATTENTION: this file only compiles on a UNO or MEGA
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// Please refer to DCCTimer.h for general comments about how this class works
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// This is to avoid repetition and duplication.
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#ifdef ARDUINO_ARCH_AVR
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#include <avr/boot.h>
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#include <avr/wdt.h>
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#include "DCCTimer.h"
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#ifdef DEBUG_ADC
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#include "TrackManager.h"
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#endif
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INTERRUPT_CALLBACK interruptHandler=0;
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// Arduino nano, uno, mega etc
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#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
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#define TIMER1_A_PIN 11
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#define TIMER1_B_PIN 12
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#define TIMER1_C_PIN 13
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#define TIMER2_A_PIN 10
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#define TIMER2_B_PIN 9
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#else
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#define TIMER1_A_PIN 9
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#define TIMER1_B_PIN 10
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#endif
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void DCCTimer::begin(INTERRUPT_CALLBACK callback) {
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interruptHandler=callback;
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noInterrupts();
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TCCR1A = 0;
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ICR1 = CLOCK_CYCLES;
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TCNT1 = 0;
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TCCR1B = _BV(WGM13) | _BV(CS10); // Mode 8, clock select 1
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TIMSK1 = _BV(TOIE1); // Enable Software interrupt
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interrupts();
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}
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void DCCTimer::startRailcomTimer(byte brakePin) {
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/* The Railcom timer is started in such a way that it
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- First triggers 28uS after the last TIMER1 tick.
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This provides an accurate offset (in High Accuracy mode)
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for the start of the Railcom cutout.
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- Sets the Railcom pin high at first tick,
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because its been setup with 100% PWM duty cycle.
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- Cycles at 436uS so the second tick is the
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correct distance from the cutout.
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- Waveform code is responsible for altering the PWM
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duty cycle to 0% any time between the first and last tick.
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(there will be 7 DCC timer1 ticks in which to do this.)
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*/
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(void) brakePin; // Ignored... works on pin 9 only
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const int cutoutDuration = 430; // Desired interval in microseconds
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// Set up Timer2 for CTC mode (Clear Timer on Compare Match)
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TCCR2A = 0; // Clear Timer2 control register A
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TCCR2B = 0; // Clear Timer2 control register B
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TCNT2 = 0; // Initialize Timer2 counter value to 0
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// Configure Phase and Frequency Correct PWM mode
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TCCR2A = (1 << COM2B1); // enable pwm on pin 9
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TCCR2A |= (1 << WGM20);
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// Set Timer 2 prescaler to 32
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TCCR2B = (1 << CS21) | (1 << CS20); // 32 prescaler
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// Set the compare match value for desired interval
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OCR2A = (F_CPU / 1000000) * cutoutDuration / 64 - 1;
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// Calculate the compare match value for desired duty cycle
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OCR2B = OCR2A+1; // set duty cycle to 100%= OCR2A)
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// Enable Timer2 output on pin 9 (OC2B)
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DDRB |= (1 << DDB1);
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// TODO Fudge TCNT2 to sync with last tcnt1 tick + 28uS
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// Previous TIMER1 Tick was at rising end-of-packet bit
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// Cutout starts half way through first preamble
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// that is 2.5 * 58uS later.
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// TCNT1 ticks 8 times / microsecond
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// auto microsendsToFirstRailcomTick=(58+58+29)-(TCNT1/8);
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// set the railcom timer counter allowing for phase-correct
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// CHris's NOTE:
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// I dont kniow quite how this calculation works out but
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// it does seems to get a good answer.
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TCNT2=193 + (ICR1 - TCNT1)/8;
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}
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void DCCTimer::ackRailcomTimer() {
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OCR2B= 0x00; // brake pin pwm duty cycle 0 at next tick
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}
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// ISR called by timer interrupt every 58uS
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ISR(TIMER1_OVF_vect){ interruptHandler(); }
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// Alternative pin manipulation via PWM control.
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bool DCCTimer::isPWMPin(byte pin) {
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return pin==TIMER1_A_PIN
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|| pin==TIMER1_B_PIN
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#ifdef TIMER1_C_PIN
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|| pin==TIMER1_C_PIN
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#endif
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;
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}
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void DCCTimer::setPWM(byte pin, bool high) {
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if (pin==TIMER1_A_PIN) {
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TCCR1A |= _BV(COM1A1);
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OCR1A= high?1024:0;
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}
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else if (pin==TIMER1_B_PIN) {
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TCCR1A |= _BV(COM1B1);
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OCR1B= high?1024:0;
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}
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#ifdef TIMER1_C_PIN
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else if (pin==TIMER1_C_PIN) {
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TCCR1A |= _BV(COM1C1);
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OCR1C= high?1024:0;
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}
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#endif
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}
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void DCCTimer::clearPWM() {
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TCCR1A= 0;
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}
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void DCCTimer::getSimulatedMacAddress(byte mac[6]) {
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for (byte i=0; i<6; i++) {
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// take the fist 3 and last 3 of the serial.
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// the first 5 of 8 are at 0x0E to 0x013
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// the last 3 of 8 are at 0x15 to 0x017
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mac[i]=boot_signature_byte_get(0x0E + i + (i>2? 4 : 0));
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}
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mac[0] &= 0xFE;
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mac[0] |= 0x02;
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}
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volatile int DCCTimer::minimum_free_memory=__INT_MAX__;
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// Return low memory value...
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int DCCTimer::getMinimumFreeMemory() {
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noInterrupts(); // Disable interrupts to get volatile value
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int retval = minimum_free_memory;
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interrupts();
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return retval;
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}
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extern char *__brkval;
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extern char *__malloc_heap_start;
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int DCCTimer::freeMemory() {
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char top;
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return __brkval ? &top - __brkval : &top - __malloc_heap_start;
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}
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void DCCTimer::reset() {
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wdt_enable( WDTO_15MS); // set Arduino watchdog timer for 15ms
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delay(50); // wait for the prescaller time to expire
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}
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#if defined(ARDUINO_AVR_MEGA) || defined(ARDUINO_AVR_MEGA2560)
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#define NUM_ADC_INPUTS 16
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#else
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#define NUM_ADC_INPUTS 8
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#endif
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uint16_t ADCee::usedpins = 0;
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uint8_t ADCee::highestPin = 0;
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int * ADCee::analogvals = NULL;
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static bool ADCusesHighPort = false;
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/*
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* Register a new pin to be scanned
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* Returns current reading of pin and
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* stores that as well
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*/
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int ADCee::init(uint8_t pin) {
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uint8_t id = pin - A0;
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if (id >= NUM_ADC_INPUTS)
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return -1023;
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if (id > 7)
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ADCusesHighPort = true;
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pinMode(pin, INPUT);
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int value = analogRead(pin);
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if (analogvals == NULL)
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analogvals = (int *)calloc(NUM_ADC_INPUTS, sizeof(int));
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analogvals[id] = value;
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usedpins |= (1<<id);
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if (id > highestPin) highestPin = id;
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return value;
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}
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int16_t ADCee::ADCmax() {
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return 1023;
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}
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/*
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* Read function ADCee::read(pin) to get value instead of analogRead(pin)
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*/
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int ADCee::read(uint8_t pin, bool fromISR) {
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uint8_t id = pin - A0;
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if ((usedpins & (1<<id) ) == 0)
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return -1023;
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// we do not need to check (analogvals == NULL)
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// because usedpins would still be 0 in that case
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if (!fromISR) noInterrupts();
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int a = analogvals[id];
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if (!fromISR) interrupts();
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return a;
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}
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/*
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* Scan function that is called from interrupt
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*/
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#pragma GCC push_options
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#pragma GCC optimize ("-O3")
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void ADCee::scan() {
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static byte id = 0; // id and mask are the same thing but it is faster to
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static uint16_t mask = 1; // increment and shift instead to calculate mask from id
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static bool waiting = false;
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if (waiting) {
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// look if we have a result
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byte low, high;
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if (bit_is_set(ADCSRA, ADSC))
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return; // no result, continue to wait
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// found value
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low = ADCL; //must read low before high
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high = ADCH;
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bitSet(ADCSRA, ADIF);
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analogvals[id] = (high << 8) | low;
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// advance at least one track
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#ifdef DEBUG_ADC
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if (id == 1) TrackManager::track[1]->setBrake(0);
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#endif
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waiting = false;
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id++;
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mask = mask << 1;
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if (id > highestPin) {
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id = 0;
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mask = 1;
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}
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}
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if (!waiting) {
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if (usedpins == 0) // otherwise we would loop forever
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return;
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// look for a valid track to sample or until we are around
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while (true) {
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if (mask & usedpins) {
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// start new ADC aquire on id
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#if defined(ADCSRB) && defined(MUX5)
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if (ADCusesHighPort) { // if we ever have started to use high pins)
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if (id > 7) // if we use a high ADC pin
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bitSet(ADCSRB, MUX5); // set MUX5 bit
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else
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bitClear(ADCSRB, MUX5);
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}
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#endif
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ADMUX=(1<<REFS0)|(id & 0x07); //select AVCC as reference and set MUX
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bitSet(ADCSRA,ADSC); // start conversion
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#ifdef DEBUG_ADC
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if (id == 1) TrackManager::track[1]->setBrake(1);
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#endif
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waiting = true;
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return;
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}
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id++;
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mask = mask << 1;
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if (id > highestPin) {
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id = 0;
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mask = 1;
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}
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}
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}
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}
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#pragma GCC pop_options
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void ADCee::begin() {
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noInterrupts();
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// ADCSRA = (ADCSRA & 0b11111000) | 0b00000100; // speed up analogRead sample time
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// Set up ADC for free running mode
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ADMUX=(1<<REFS0); //select AVCC as reference. We set MUX later
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ADCSRA = (1<<ADEN)|(1 << ADPS2); // ADPS2 means divisor 32 and 16Mhz/32=500kHz.
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//bitSet(ADCSRA, ADSC); //do not start the ADC yet. Done when we have set the MUX
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interrupts();
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}
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#endif
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