mirror of
https://github.com/DCC-EX/CommandStation-EX.git
synced 2024-12-23 21:01:25 +01:00
212 lines
6.9 KiB
C++
212 lines
6.9 KiB
C++
/*
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* © 2021 Neil McKechnie
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* © 2021 Mike S
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* © 2021 Fred Decker
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* © 2020-2021 Harald Barth
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* © 2020-2021 Chris Harlow
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* All rights reserved.
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*
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* This file is part of CommandStation-EX
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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 "DCCWaveform.h"
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#include "TrackManager.h"
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#include "DCCTimer.h"
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#include "DCCACK.h"
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#include "DIAG.h"
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DCCWaveform DCCWaveform::mainTrack(PREAMBLE_BITS_MAIN, true);
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DCCWaveform DCCWaveform::progTrack(PREAMBLE_BITS_PROG, false);
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bool DCCWaveform::progTrackSyncMain=false;
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bool DCCWaveform::progTrackBoosted=false;
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int16_t DCCWaveform::joinRelay=UNUSED_PIN;
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void DCCWaveform::begin() {
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TrackManager::setPower(POWERMODE::OFF);
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DCCTimer::begin(DCCWaveform::interruptHandler);
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}
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void DCCWaveform::loop() {
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DCCACK::loop();
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TrackManager::loop(DCCACK::isActive() || progTrackSyncMain || progTrackBoosted );
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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 DCCWaveform::interruptHandler() {
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// call the timer edge sensitive actions for progtrack and maintrack
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// member functions would be cleaner but have more overhead
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byte sigMain=signalTransform[mainTrack.state];
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byte sigProg=progTrackSyncMain? sigMain : signalTransform[progTrack.state];
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// Set the signal state for both tracks
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TrackManager::setDCCSignal(sigMain);
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TrackManager::setPROGSignal(sigProg);
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// Move on in the state engine
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mainTrack.state=stateTransform[mainTrack.state];
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progTrack.state=stateTransform[progTrack.state];
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// WAVE_PENDING means we dont yet know what the next bit is
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if (mainTrack.state==WAVE_PENDING) mainTrack.interrupt2();
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if (progTrack.state==WAVE_PENDING) progTrack.interrupt2();
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else DCCACK::checkAck(progTrack.sentResetsSincePacket);
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}
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#pragma GCC push_options
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void DCCWaveform::setJoinRelayPin(byte joinRelayPin) {
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joinRelay=joinRelayPin;
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if (joinRelay!=UNUSED_PIN) {
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pinMode(joinRelay,OUTPUT);
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digitalWrite(joinRelay,LOW); // LOW is relay disengaged
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}
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}
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void DCCWaveform::setJoin(bool joined) {
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progTrackSyncMain=joined;
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if (joinRelay!=UNUSED_PIN) digitalWrite(joinRelay,joined?HIGH:LOW);
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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) {
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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 = WAVE_START;
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// The +1 below is to allow the preamble generator to create the stop bit
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// for 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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}
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// For each state of the wave nextState=stateTransform[currentState]
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const WAVE_STATE DCCWaveform::stateTransform[]={
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/* WAVE_START -> */ WAVE_PENDING,
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/* WAVE_MID_1 -> */ WAVE_START,
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/* WAVE_HIGH_0 -> */ WAVE_MID_0,
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/* WAVE_MID_0 -> */ WAVE_LOW_0,
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/* WAVE_LOW_0 -> */ WAVE_START,
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/* WAVE_PENDING (should not happen) -> */ WAVE_PENDING};
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// For each state of the wave, signal pin is HIGH or LOW
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const bool DCCWaveform::signalTransform[]={
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/* WAVE_START -> */ HIGH,
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/* WAVE_MID_1 -> */ LOW,
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/* WAVE_HIGH_0 -> */ HIGH,
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/* WAVE_MID_0 -> */ LOW,
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/* WAVE_LOW_0 -> */ LOW,
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/* WAVE_PENDING (should not happen) -> */ LOW};
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#pragma GCC push_options
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#pragma GCC optimize ("-O3")
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void DCCWaveform::interrupt2() {
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// calculate the next bit to be sent:
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// set state WAVE_MID_1 for a 1=bit
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// or WAVE_HIGH_0 for a 0 bit.
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if (remainingPreambles > 0 ) {
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state=WAVE_MID_1; // switch state to trigger LOW on next interrupt
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remainingPreambles--;
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// Update free memory diagnostic as we don't have anything else to do this time.
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// Allow for checkAck and its called functions using 22 bytes more.
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DCCTimer::updateMinimumFreeMemoryISR(22);
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return;
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}
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// Wave has gone HIGH but what happens next depends on the bit to be transmitted
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// beware OF 9-BIT MASK generating a zero to start each byte
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state=(transmitPacket[bytes_sent] & bitMask[bits_sent])? WAVE_MID_1 : WAVE_HIGH_0;
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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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// a fixed length memcpy is faster than a variable length loop for these small lengths
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// for (int b = 0; b < pendingLength; b++) transmitPacket[b] = pendingPacket[b];
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memcpy( transmitPacket, pendingPacket, sizeof(pendingPacket));
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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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#pragma GCC pop_options
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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 (byte 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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// buffer is MAX_PACKET_SIZE but pendingPacket is one bigger
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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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#pragma GCC push_options
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#pragma GCC optimize ("-O3")
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#pragma GCC pop_options
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