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@@ -0,0 +1,141 @@
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+/*
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+ * FrSky Telemetry Protocol Host implementation.
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+ * Copyright 2016 by Thomas Buck <xythobuz@xythobuz.de>
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+ *
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+ * Based on the FrSky Telemetry Protocol documentation:
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+ * http://www.frsky-rc.com/download/down.php?id=128
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+ *
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+ * This program is free software; you can redistribute it and/or
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+ * modify it under the terms of the GNU General Public License as
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+ * published by the Free Software Foundation, version 2.
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+ */
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+
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+#include "frsky.h"
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+
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+#define DEBUG_OUTPUT Serial
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+
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+FrSky::FrSky(Stream* s) : serial(s), dataHandler(0),
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+ alarmThresholdHandler(0), userDataHandler(0), bufferIndex(0) {
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+ for (uint8_t i = 0; i < userDataSize; i++) {
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+ userData[i] = 0;
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+ }
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+
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+ for (uint8_t i = 0; i < bufferSize; i++) {
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+ buffer[i] = 0;
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+ }
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+}
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+
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+void FrSky::poll() {
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+ if ((!serial) || (!serial->available())) {
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+ return;
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+ }
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+
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+ uint8_t c = serial->read();
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+ if (c == delimiter) {
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+ if (bufferIndex < minPacketSize) {
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+ bufferIndex = 0;
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+ }
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+ if (bufferIndex >= bufferSize) {
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+ bufferIndex = bufferSize - 1;
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+ }
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+ buffer[bufferIndex++] = c;
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+ if (bufferIndex > minPacketSize) {
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+ handleMessage();
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+ bufferIndex = 0;
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+ }
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+ } else if ((bufferIndex > 0) && (bufferIndex < bufferSize)) {
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+ buffer[bufferIndex++] = c;
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+ }
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+}
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+
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+void FrSky::pollAlarms() {
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+ serial->write(delimiter);
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+ writeEscaped(idGetAlarms);
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+ for (uint8_t i = 0; i < 8; i++) {
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+ writeEscaped(0);
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+ }
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+ serial->write(delimiter);
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+}
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+
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+void FrSky::setAlarm(AlarmThreshold alarm) {
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+ uint8_t id = (alarm.id == analog1_1) ? idAlarm0
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+ : ((alarm.id == analog1_2) ? idAlarm1
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+ : ((alarm.id == analog2_1) ? idAlarm2 : idAlarm3));
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+ serial->write(delimiter);
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+ writeEscaped(id);
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+ writeEscaped(alarm.value);
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+ writeEscaped(alarm.dir);
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+ writeEscaped(alarm.level);
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+ for (uint8_t i = 0; i < 5; i++) {
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+ writeEscaped(0);
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+ }
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+ serial->write(delimiter);
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+}
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+
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+void FrSky::writeEscaped(uint8_t v) {
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+ if ((v == delimiter) || (v == escape)) {
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+ v ^= key;
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+ serial->write(escape);
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+ }
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+ serial->write(v);
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+}
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+
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+void FrSky::handleMessage() {
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+#ifdef DEBUG_OUTPUT
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+ DEBUG_OUTPUT.println("FrSky::handleMessage()");
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+ for (uint8_t i = 0; i < bufferIndex; i++) {
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+ DEBUG_OUTPUT.print(buffer[i], HEX);
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+ }
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+ DEBUG_OUTPUT.println();
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+#endif
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+
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+ if ((buffer[0] != delimiter) || (buffer[bufferIndex - 1] != delimiter)) {
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+#ifdef DEBUG_OUTPUT
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+ DEBUG_OUTPUT.println("invalid packet begin/end!");
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+#endif
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+ return;
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+ }
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+
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+ // Fix escaped bytes
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+ for (uint8_t i = 0; i < (bufferIndex - 1); i++) {
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+ if (buffer[i] == escape) {
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+ buffer[i] = buffer[i + 1] ^ key;
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+ for (uint8_t j = i + 1; j < (bufferIndex - 1); j++) {
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+ buffer[j] = buffer[j + 1];
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+ }
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+ bufferIndex--;
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+ }
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+ }
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+
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+ if (buffer[1] == idVoltageQuality) {
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+ if (dataHandler) {
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+ dataHandler(buffer[2], buffer[3], buffer[4], buffer[5]);
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+ }
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+ } else if (buffer[1] == idUserData) {
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+ uint8_t len = buffer[2];
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+ if (len > userDataSize) {
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+ len = userDataSize;
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+ }
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+ for (uint8_t i = 0; i < len; i++) {
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+ userData[i] = buffer[i + 4];
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+ }
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+ if ((len > 0) && (userDataHandler)) {
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+ userDataHandler(userData, len);
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+ }
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+ } else if ((buffer[1] == idAlarm0) || (buffer[1] == idAlarm1)
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+ || (buffer[1] == idAlarm2) || (buffer[1] == idAlarm3)) {
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+ AnalogValue v = (buffer[1] == idAlarm0) ? analog1_1
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+ : ((buffer[1] == idAlarm1) ? analog1_2
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+ : ((buffer[1] == idAlarm2) ? analog2_1 : analog2_2));
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+ if (alarmThresholdHandler) {
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+ alarmThresholdHandler(AlarmThreshold(v, (GreaterLessThan)buffer[3],
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+ (AlarmLevel)buffer[4], buffer[2]));
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+ }
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+ } else {
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+#ifdef DEBUG_OUTPUT
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+ DEBUG_OUTPUT.print("Unexpected ID: ");
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+ DEBUG_OUTPUT.println(buffer[1], HEX);
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+#endif
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+ }
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+}
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+
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