mirror of
https://github.com/DCC-EX/CommandStation-EX.git
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315 lines
10 KiB
C++
315 lines
10 KiB
C++
/*
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* © 2020, Chris Harlow. 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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#include <Arduino.h>
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#include "Hardware.h"
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#include "DCCWaveform.h"
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#include "DIAG.h"
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DCCWaveform DCCWaveform::mainTrack(PREAMBLE_BITS_MAIN, true, (int)(MAIN_MAX_MILLIAMPS / MAIN_SENSE_FACTOR));
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DCCWaveform DCCWaveform::progTrack(PREAMBLE_BITS_PROG, false, (int)(PROG_MAX_MILLIAMPS / PROG_SENSE_FACTOR));
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const int ACK_MIN_PULSE_RAW=65 / PROG_SENSE_FACTOR;
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bool DCCWaveform::progTrackSyncMain=false;
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void DCCWaveform::begin() {
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Hardware::init();
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Hardware::setCallback(58, interruptHandler);
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mainTrack.beginTrack();
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progTrack.beginTrack();
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}
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void DCCWaveform::loop() {
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mainTrack.checkPowerOverload();
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progTrack.checkPowerOverload();
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}
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// static //
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void DCCWaveform::interruptHandler() {
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// call the timer edge sensitive actions for progtrack and maintrack
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bool mainCall2 = mainTrack.interrupt1();
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bool progCall2 = progTrack.interrupt1();
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// call (if necessary) the procs to get the current bits
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// these must complete within 50microsecs of the interrupt
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// but they are only called ONCE PER BIT TRANSMITTED
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// after the rising edge of the signal
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if (mainCall2) mainTrack.interrupt2();
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if (progCall2) progTrack.interrupt2();
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}
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// An instance of this class handles the DCC transmissions for one track. (main or prog)
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// Interrupts are marshalled via the statics.
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// A track has a current transmit buffer, and a pending buffer.
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// When the current buffer is exhausted, either the pending buffer (if there is one waiting) or an idle buffer.
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// This bitmask has 9 entries as each byte is trasmitted as a zero + 8 bits.
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const byte bitMask[] = {0x00, 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01};
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DCCWaveform::DCCWaveform( byte preambleBits, bool isMain, int rawCurrentTrip) {
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// establish appropriate pins
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rawCurrentTripValue=rawCurrentTrip;
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isMainTrack = isMain;
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packetPending = false;
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memcpy(transmitPacket, idlePacket, sizeof(idlePacket));
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state = 0;
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// The +1 below is to allow the preamble generator to create the stop bit
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// fpr the previous packet.
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requiredPreambles = preambleBits+1;
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bytes_sent = 0;
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bits_sent = 0;
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sampleDelay = 0;
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lastSampleTaken = millis();
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ackPending=false;
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}
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void DCCWaveform::beginTrack() {
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setPowerMode(POWERMODE::ON);
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}
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POWERMODE DCCWaveform::getPowerMode() {
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return powerMode;
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}
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void DCCWaveform::setPowerMode(POWERMODE mode) {
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powerMode = mode;
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Hardware::setPower(isMainTrack, mode == POWERMODE::ON);
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if (mode == POWERMODE::ON) delay(200);
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}
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void DCCWaveform::checkPowerOverload() {
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if (millis() - lastSampleTaken < sampleDelay) return;
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lastSampleTaken = millis();
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int tripValue= rawCurrentTripValue;
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if (!isMainTrack && (ackPending || progTrackSyncMain)) tripValue=ACK_CURRENT_TRIP;
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switch (powerMode) {
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case POWERMODE::OFF:
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sampleDelay = POWER_SAMPLE_OFF_WAIT;
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break;
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case POWERMODE::ON:
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// Check current
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lastCurrent = Hardware::getCurrentRaw(isMainTrack);
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if (lastCurrent <= tripValue) sampleDelay = POWER_SAMPLE_ON_WAIT;
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else {
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setPowerMode(POWERMODE::OVERLOAD);
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unsigned int mA=Hardware::getCurrentMilliamps(isMainTrack,lastCurrent);
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unsigned int maxmA=Hardware::getCurrentMilliamps(isMainTrack,tripValue);
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DIAG(F("\n*** %S TRACK POWER OVERLOAD current=%d max=%d ***\n"), isMainTrack ? F("MAIN") : F("PROG"), mA, maxmA);
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sampleDelay = POWER_SAMPLE_OVERLOAD_WAIT;
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}
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break;
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case POWERMODE::OVERLOAD:
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// Try setting it back on after the OVERLOAD_WAIT
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setPowerMode(POWERMODE::ON);
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sampleDelay = POWER_SAMPLE_ON_WAIT;
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break;
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default:
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sampleDelay = 999; // cant get here..meaningless statement to avoid compiler warning.
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}
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}
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// process time-edge sensitive part of interrupt
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// return true if second level required
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bool DCCWaveform::interrupt1() {
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// NOTE: this must consume transmission buffers even if the power is off
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// otherwise can cause hangs in main loop waiting for the pendingBuffer.
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switch (state) {
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case 0: // start of bit transmission
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setSignal(HIGH);
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state = 1;
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return true; // must call interrupt2 to set currentBit
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case 1: // 58us after case 0
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if (currentBit) {
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setSignal(LOW);
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state = 0;
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}
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else state = 2;
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break;
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case 2: // 116us after case 0
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setSignal(LOW);
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state = 3;
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break;
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case 3: // finished sending zero bit
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state = 0;
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break;
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}
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// ACK check is prog track only and will only be checked if
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// this is not case(0) which needs relatively expensive packet change code to be called.
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if (ackPending) checkAck();
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return false;
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}
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void DCCWaveform::setSignal(bool high) {
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if (progTrackSyncMain) {
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if (!isMainTrack) return; // ignore PROG track waveform while in sync
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// set both tracks to same signal
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Hardware::setSignal(true, high);
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Hardware::setSignal(false, high);
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return;
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}
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Hardware::setSignal(isMainTrack,high);
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}
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void DCCWaveform::interrupt2() {
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// set currentBit to be the next bit to be sent.
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if (remainingPreambles > 0 ) {
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currentBit = true;
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remainingPreambles--;
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return;
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}
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// beware OF 9-BIT MASK generating a zero to start each byte
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currentBit = transmitPacket[bytes_sent] & bitMask[bits_sent];
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bits_sent++;
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// If this is the last bit of a byte, prepare for the next byte
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if (bits_sent == 9) { // zero followed by 8 bits of a byte
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//end of Byte
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bits_sent = 0;
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bytes_sent++;
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// if this is the last byte, prepere for next packet
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if (bytes_sent >= transmitLength) {
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// end of transmission buffer... repeat or switch to next message
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bytes_sent = 0;
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remainingPreambles = requiredPreambles;
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if (transmitRepeats > 0) {
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transmitRepeats--;
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}
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else if (packetPending) {
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// Copy pending packet to transmit packet
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for (int b = 0; b < pendingLength; b++) transmitPacket[b] = pendingPacket[b];
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transmitLength = pendingLength;
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transmitRepeats = pendingRepeats;
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packetPending = false;
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sentResetsSincePacket=0;
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}
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else {
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// Fortunately reset and idle packets are the same length
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memcpy( transmitPacket, isMainTrack ? idlePacket : resetPacket, sizeof(idlePacket));
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transmitLength = sizeof(idlePacket);
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transmitRepeats = 0;
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if (sentResetsSincePacket<250) sentResetsSincePacket++;
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}
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}
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}
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}
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// Wait until there is no packet pending, then make this pending
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void DCCWaveform::schedulePacket(const byte buffer[], byte byteCount, byte repeats) {
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if (byteCount >= MAX_PACKET_SIZE) return; // allow for chksum
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while (packetPending);
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byte checksum = 0;
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for (int b = 0; b < byteCount; b++) {
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checksum ^= buffer[b];
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pendingPacket[b] = buffer[b];
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}
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pendingPacket[byteCount] = checksum;
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pendingLength = byteCount + 1;
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pendingRepeats = repeats;
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packetPending = true;
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sentResetsSincePacket=0;
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}
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int DCCWaveform::getLastCurrent() {
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return lastCurrent;
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}
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// Operations applicable to PROG track ONLY.
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// (yes I know I could have subclassed the main track but...)
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void DCCWaveform::setAckBaseline(bool debug) {
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if (isMainTrack) return;
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ackThreshold=Hardware::getCurrentRaw(false) + ACK_MIN_PULSE_RAW;
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if (debug) DIAG(F("\nACK-BASELINE %d/%dmA"),ackThreshold,Hardware::getCurrentMilliamps(false,ackThreshold));
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}
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void DCCWaveform::setAckPending(bool debug) {
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if (isMainTrack) return;
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(void)debug;
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ackMaxCurrent=0;
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ackPulseStart=0;
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ackPulseDuration=0;
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ackDetected=false;
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ackCheckStart=millis();
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ackPending=true; // interrupt routines will now take note
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}
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byte DCCWaveform::getAck(bool debug) {
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if (ackPending) return (2); // still waiting
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if (debug) DIAG(F("\nACK-%S after %dmS max=%d/%dmA pulse=%duS"),ackDetected?F("OK"):F("FAIL"), ackCheckDuration,
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ackMaxCurrent,Hardware::getCurrentMilliamps(false,ackMaxCurrent), ackPulseDuration);
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if (ackDetected) return (1); // Yes we had an ack
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return(0); // pending set off but not detected means no ACK.
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}
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void DCCWaveform::checkAck() {
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// This function operates in interrupt() time so must be fast and can't DIAG
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if (sentResetsSincePacket > 6) { //ACK timeout
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ackCheckDuration=millis()-ackCheckStart;
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ackPending = false;
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return;
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}
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lastCurrent=Hardware::getCurrentRaw(false);
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if (lastCurrent > ackMaxCurrent) ackMaxCurrent=lastCurrent;
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// An ACK is a pulse lasting between MIN_ACK_PULSE_DURATION and MAX_ACK_PULSE_DURATION uSecs (refer @haba)
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if (lastCurrent>ackThreshold) {
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if (ackPulseStart==0) ackPulseStart=micros(); // leading edge of pulse detected
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return;
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}
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// not in pulse
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if (ackPulseStart==0) return; // keep waiting for leading edge
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// detected trailing edge of pulse
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ackPulseDuration=micros()-ackPulseStart;
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if (ackPulseDuration>=MIN_ACK_PULSE_DURATION && ackPulseDuration<=MAX_ACK_PULSE_DURATION) {
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ackCheckDuration=millis()-ackCheckStart;
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ackDetected=true;
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ackPending=false;
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transmitRepeats=0; // shortcut remaining repeat packets
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return; // we have a genuine ACK result
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}
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ackPulseStart=0; // We have detected a too-short or too-long pulse so ignore and wait for next leading edge
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}
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