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// This software is intended to be run on a small Arduino (e.g., a Pro Mini),
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// whose purpose is dedicated to talking to the RC system. That is to say, it
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// listens to the PPM signal from the RC receiver and produces a compatible
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// single for the ESCs to control the motors. It additionally talks to the main
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// board via a trivial serial protocol. In so doing, this software relieves the
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// main board (and software running on it) of the task of interfacing with any
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// The 8 channels (from the RC receiver) need to be combined and fed to two
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// interrupts on the Arduino. They need to be combined in such a way as to
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// alternate pulses between the two interrupts (which are alternately used to
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// read the pulses). Like this:
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// ch1 ch3 ch5 ch7 ch2 ch4 ch6 ch8
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// ___ | | | | | | | | ___
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// GND ---|___|---+----+----+----+ +----+----+----+----|___|--- GND
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// ________________________ | __ | _____________________
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// (interrupt 0) (interrupt 1)
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// The two resistors in the circuit are pull-down resistors (so, say 100kΩ).
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// Without them, the Arduino is unable to read the pulse wave at all.
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// Note that your receiver may not send pulses sequentially, in "channel order".
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// If this turns out to be the case, you will need to arrange for the pulses to
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// wire up the channels in an order whereby the pulses arrive alternately
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// between the two interrupts and adjust the channel order in config.h.
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// The four motor control outputs should be fed directly to the ESCs.
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// ___________________ | __ | __ | __ | _____
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// pin 4 o o o o pin 7
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// The serial interface (pins 0 and 1) talk a very simple protocol. When a
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// complete set of 8 channel values have been read, it writes 0xffff followed by
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// the 8, 16-bit unsigned channel values. It expects to recieve 0xffff,
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// followed by 4, 16-bit unsigned channel values. All channel values are in the
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// range specified in config.h.
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static bool on = false;
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digitalWrite( LED_PIN, on? HIGH : LOW );
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pinMode( LED_PIN, OUTPUT );
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digitalWrite( LED_PIN, LOW );
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int motor_values[ NUM_MOTORS ];
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int channel_values[ NUM_CHANNELS ];
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// reset the motor values
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for( int a = 0; a < NUM_MOTORS; a++ )
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motor_values[ a ] = 0;
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// have we read a whole set of channel values?
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if( Receiver::read_channels( channel_values ) )
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// send channel values to main board
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Comms::write_channels( channel_values );
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// read channel values from main board
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if( Comms::read_channels( motor_values ) )
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Motors::set_values( motor_values );
added
removed
src/rc-interface/main.ino
