mirror of https://github.com/ArduPilot/ardupilot
280 lines
7.0 KiB
Plaintext
280 lines
7.0 KiB
Plaintext
/*
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OBC failsafe board
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Jack Pittar and Andrew Tridgell
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public License
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as published by the Free Software Foundation; either version 2.1
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of the License, or (at your option) any later version.
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*/
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#define MODE_PWM_PIN 9 //Command pulse read on input 11
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#define MUXA_PIN 3 // H H rc , L H micro
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#define MUXB_PIN 4 // H L backup, L L prime
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#define LED_PIN 13
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#define OBC_MODE_PIN 12 //high for OBC termination settings
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#define AILERON_PIN 5
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#define ELEVATOR_PIN 6
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#define THROTTLE_PIN 7
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#define RUDDER_PIN 8
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#define HEARTBEAT_PRIMARY_PIN 11
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#define TERMINATE_PRIMARY_PIN 10
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#define HEARTBEAT_BACKUP_PIN A1
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#define TERMINATE_BACKUP_PIN A0
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// set to 1 if backup autopilot is installed
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#define BACKUP_AUTOPILOT_INSTALLED 0
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enum mux_mode {
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MUX_MODE_RC = 1,
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MUX_MODE_MICRO = 2,
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MUX_MODE_BACKUP = 3,
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MUX_MODE_PRIMARY = 4
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};
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// heartbeat status
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static bool heartbeat_primary_ok = true;
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static bool heartbeat_backup_ok = true;
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// check heartbeat status
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static void update_heartbeat(void)
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{
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static uint8_t last_hb_primary;
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static uint8_t last_hb_backup;
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static uint32_t last_primary_t;
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static uint32_t last_backup_t;
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uint8_t hb_primary = digitalRead(HEARTBEAT_PRIMARY_PIN);
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uint8_t hb_backup = digitalRead(HEARTBEAT_BACKUP_PIN);
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uint32_t tnow = millis();
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// Serial.println(hb_primary);
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// we consider the heartbeat to be OK if it changed in the
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// last 0.4 seconds
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const uint32_t hb_check_time = 400;
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if (hb_primary != last_hb_primary) {
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last_hb_primary = hb_primary;
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last_primary_t = tnow;
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//Serial.println("hb1 change");
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}
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if (hb_backup != last_hb_backup) {
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last_hb_backup = hb_backup;
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last_backup_t = tnow;
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//Serial.println("hb2 change");
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}
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if (tnow < hb_check_time) {
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// not enough time has passed for a measurement
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return;
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}
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heartbeat_primary_ok = ((tnow - last_primary_t) < hb_check_time);
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heartbeat_backup_ok = ((tnow - last_backup_t) < hb_check_time);
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}
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static void set_mux_mode(uint8_t mode)
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{
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switch ((enum mux_mode)mode) {
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case MUX_MODE_RC:
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digitalWrite(MUXA_PIN, HIGH);
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digitalWrite(MUXB_PIN, HIGH);
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break;
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case MUX_MODE_MICRO:
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digitalWrite(MUXA_PIN, LOW);
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digitalWrite(MUXB_PIN, HIGH);
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break;
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case MUX_MODE_BACKUP:
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digitalWrite(MUXA_PIN, HIGH);
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digitalWrite(MUXB_PIN, LOW);
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break;
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case MUX_MODE_PRIMARY:
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digitalWrite(MUXA_PIN, LOW);
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digitalWrite(MUXB_PIN, LOW);
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break;
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}
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}
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// send pulses to servos
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static void set_servos(uint16_t aileron, uint16_t elevator,
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uint16_t throttle, uint16_t rudder)
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{
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digitalWrite(AILERON_PIN, HIGH);
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delayMicroseconds(aileron);
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digitalWrite(AILERON_PIN, LOW);
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digitalWrite(ELEVATOR_PIN, HIGH);
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delayMicroseconds(elevator);
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digitalWrite(ELEVATOR_PIN, LOW);
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digitalWrite(THROTTLE_PIN, HIGH);
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delayMicroseconds(throttle);
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digitalWrite(THROTTLE_PIN, LOW);
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digitalWrite(RUDDER_PIN, HIGH);
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delayMicroseconds(rudder);
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digitalWrite(RUDDER_PIN, LOW);
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}
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static void set_servos_terminate(uint8_t obc_mode)
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{
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set_mux_mode(MUX_MODE_MICRO);
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if (obc_mode) {
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set_servos(1000, 2000, 1000, 1000);
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} else {
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set_servos(1500, 1500, 1200, 1500);
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}
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}
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void setup()
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{
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// input pins
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pinMode(HEARTBEAT_PRIMARY_PIN, INPUT);
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pinMode(TERMINATE_PRIMARY_PIN, INPUT);
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pinMode(HEARTBEAT_BACKUP_PIN, INPUT);
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pinMode(TERMINATE_BACKUP_PIN, INPUT);
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pinMode(MODE_PWM_PIN, INPUT);
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pinMode(OBC_MODE_PIN, INPUT);
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// output pins
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pinMode(LED_PIN, OUTPUT);
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pinMode(MUXA_PIN, OUTPUT);
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pinMode(MUXB_PIN, OUTPUT);
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pinMode(AILERON_PIN, OUTPUT);
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pinMode(ELEVATOR_PIN, OUTPUT);
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pinMode(THROTTLE_PIN, OUTPUT);
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pinMode(RUDDER_PIN, OUTPUT);
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digitalWrite(LED_PIN, LOW);
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set_mux_mode(MUX_MODE_MICRO);
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Serial.begin(115200);
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Serial.println("OBC Failsafe Starting\n");
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}
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void loop()
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{
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static uint32_t last_status_t;
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uint32_t tnow = millis();
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static uint8_t led_state;
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static bool has_terminated = false;
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static uint8_t termination_counter;
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static uint16_t loop_counter;
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loop_counter++;
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// check for heartbeat
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update_heartbeat();
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// see if we are in manual mode. Note that on the Uno,
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// pulseIn is not very accurate. The +90 brings us much closer
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// to the real pulse width
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uint16_t mode_pwm = pulseIn(MODE_PWM_PIN, HIGH, 25000) + 90;
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uint16_t manual_mode = (mode_pwm > 1750 && mode_pwm < 2100);
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// check the state of the terminate pins
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uint8_t terminate_primary = digitalRead(TERMINATE_PRIMARY_PIN);
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uint8_t terminate_backup = digitalRead(TERMINATE_BACKUP_PIN);
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// see if the OBC mode jumper is set
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uint8_t obc_mode = digitalRead(OBC_MODE_PIN);
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if (tnow - last_status_t > 1000) {
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last_status_t = tnow;
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// show status once a second
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Serial.print("OBC:"); Serial.print(obc_mode);
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Serial.print(" Mode:"); Serial.print(mode_pwm);
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Serial.print(" HB1:"); Serial.print(heartbeat_primary_ok);
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Serial.print(" HB2:"); Serial.print(heartbeat_backup_ok);
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Serial.print(" TERM1:"); Serial.print(terminate_primary);
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Serial.print(" TERM2:"); Serial.print(terminate_backup);
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Serial.print(" TERMINATED:"); Serial.print(has_terminated);
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Serial.print(" LOOP:"); Serial.print(loop_counter);
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Serial.println();
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delayMicroseconds(5000);
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loop_counter = 0;
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// flash LED once a second so we know failsafe board
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// is working
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led_state = !led_state;
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digitalWrite(LED_PIN, led_state);
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}
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// allow reset via serial connection
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if (Serial.available() > 0) {
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char c = (char)Serial.read();
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if (c == 'r') {
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Serial.println("RESET BOARD");
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has_terminated = false;
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termination_counter = 0;
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}
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}
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// if we are not in OBC mode, and the mode control
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// channel is high, then give RC control
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if (!obc_mode && manual_mode) {
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// give manual control via RC
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set_mux_mode(MUX_MODE_RC);
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return;
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}
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#if BACKUP_AUTOPILOT_INSTALLED == 0
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terminate_backup = false;
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#endif
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// see if termination is set by a functioning autopilot
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if (heartbeat_primary_ok && terminate_primary) {
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termination_counter++;
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} else if (heartbeat_backup_ok && terminate_backup) {
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termination_counter++;
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} else if (obc_mode && !heartbeat_primary_ok && !heartbeat_backup_ok) {
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// if in OBC mode and neither autopilot is OK, then
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// terminate
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termination_counter++;
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} else {
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termination_counter = 0;
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}
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// use the termination counter to debounce the termination
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// pins
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if (termination_counter > 10) {
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termination_counter = 0;
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has_terminated = true;
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}
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// if we have terminated then setup the servos
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if (has_terminated) {
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set_servos_terminate(obc_mode);
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return;
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}
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bool heartbeat_ok = heartbeat_primary_ok;
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#if BACKUP_AUTOPILOT_INSTALLED
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if (heartbeat_backup_ok) {
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heartbeat_ok = true;
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}
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#endif
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if (heartbeat_ok) {
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// at least one autopilot is healthy
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if (manual_mode) {
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// we want manual/RC control
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set_mux_mode(MUX_MODE_RC);
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} else if (heartbeat_primary_ok) {
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set_mux_mode(MUX_MODE_PRIMARY);
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} else {
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set_mux_mode(MUX_MODE_BACKUP);
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}
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} else {
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// neither autopilot is OK
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if (obc_mode) {
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set_servos_terminate(obc_mode);
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} else {
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// give RC control
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set_mux_mode(MUX_MODE_RC);
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}
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}
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}
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