mirror of https://github.com/ArduPilot/ardupilot
959 lines
32 KiB
C
959 lines
32 KiB
C
// !!!!!!!!!! EXPERIMENTAL TEST VERSION - USE WITH CAUTION - DO NOT RELEASE PUBLIC FIRMWARE !!!!!!!!!!
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// -------------------------------------------------------------
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// PPM ENCODER V2.3.11
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// -------------------------------------------------------------
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// Improved servo to ppm for ArduPilot MEGA v1.x (ATmega328p),
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// PhoneDrone and APM2 (ATmega32u2)
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// By: John Arne Birkeland - 2012
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// APM v1.x adaptation and "difficult" receiver testing by Olivier ADLER
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// -------------------------------------------------------------
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// Changelog:
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// 01-08-2011
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// V2.2.3 - Changed back to BLOCKING interrupts.
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// Assembly PPM compare interrupt can be switch back to non-blocking, but not recommended.
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// V2.2.3 - Implemented 0.5us cut filter to remove servo input capture jitter.
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// 04-08-2011
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// V2.2.4 - Implemented PPM passtrough funtion.
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// Shorting channel 2&3 enabled ppm passtrough on channel 1.
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// 04-08-2011
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// V2.2.5 - Implemented simple average filter to smooth servo input capture jitter.
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// Takes fewer clocks to execute and has better performance then cut filter.
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// 05-08-2011
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// V2.2.51 - Minor bug fixes.
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// 06-08-2011
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// V2.2.6 - PPM passtrough failsafe implemented.
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// The PPM generator will be activated and output failsafe values while ppm passtrough signal is missing.
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// 01-09-2011
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// V2.2.61 - Temporary MUX pin always high patch for APM beta board
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// 22-09-2011
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// V2.2.62 - ATmegaXXU2 USB connection status pin (PC2) for APM UART MUX selection (removed temporary high patch)
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// - Removed assembly optimized PPM generator (not usable for production release)
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// 23-09-2011
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// V2.2.63 - Average filter disabled
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// 24-09-2011
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// V2.2.64 - Added distincts Power on / Failsafe PPM values
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// - Changed CH5 (mode selection) PPM Power on and Failsafe values to 1555 (Flight mode 4)
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// - Added brownout detection : Failsafe values are copied after a brownout reset instead of power on values
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// 25-09-2011
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// V2.2.65 - Implemented PPM output delay until input signal is detected (PWM and PPM pass-trough mode)
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// - Changed brownout detection and FailSafe handling to work with XXU2 chips
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// - Minor variable and define naming changes to enhance readability
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// 15-03-2012
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// V2.2.66 - Added APM2 (ATmega32U2) support for using TX and RX status leds to indicate PWM and PPM traffic
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// - <RX>: <OFF> = no pwm input detected, <TOGGLE> = speed of toggle indicate how many channel are active, <ON> = input lost (failsafe)
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// - <TX>: <OFF> = ppm output not started, <FAST TOGGLE> = normal PWM->PPM output or PPM passtrough failsafe, <SLOW TOGGLE> = PPM passtrough
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// 03-06-2012
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// V2.2.67 - Implemented detection and failsafe (throttle = 900us) for missing throttle signal.
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// 04-06-2012
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// V2.2.68 - Fixed possible logic flaw in throttle failsafe reset if _JITTER_FILTER_ is enabled
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// 02-11-2012
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// V2.2.69 - Added PPM output positive polarity - mainly for standalone PPM encoder board use
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// 03-11-2012
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// V2.3.0 - Implemented single channel fail-safe detection for all inputs
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// 16-11-2012
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// V2.3.1 - Improved watchdog timer reset, so that only valid input signals will prevent the watchdog timer from triggering
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// 22-11-2012
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// V2.3.11 - Very experimental test forcing throttle fail-safe (RTL) on single channel loss. !DO NOT RELEASE TO PUBLIC!
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// - Test for active input channels during init
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// -------------------------------------------------------------
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#ifndef _PPM_ENCODER_H_
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#define _PPM_ENCODER_H_
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#include <avr/io.h>
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// -------------------------------------------------------------
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#include <avr/interrupt.h>
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#include <avr/wdt.h>
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#include <util/delay.h>
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// -------------------------------------------------------------
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// SERVO INPUT FILTERS
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// -------------------------------------------------------------
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// Using both filters is not recommended and may reduce servo input resolution
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// #define _AVERAGE_FILTER_ // Average filter to smooth servo input capture jitter
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// #define _JITTER_FILTER_ // Cut filter to remove 0,5us servo input capture jitter
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// -------------------------------------------------------------
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#ifndef F_CPU
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#define F_CPU 16000000UL
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#endif
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#ifndef true
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#define true 1
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#endif
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#ifndef false
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#define false 0
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#endif
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#ifndef bool
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#define bool _Bool
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#endif
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// Version stamp for firmware hex file ( decode hex file using <avr-objdump -s file.hex> and look for "ArduPPM" string )
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const char ver[15] = "ArduPPMv2.3.11";
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// -------------------------------------------------------------
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// INPUT MODE
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// -------------------------------------------------------------
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#define JUMPER_SELECT_MODE 0 // Default - PPM passtrough mode selected if channel 2&3 shorted. Normal servo input (pwm) if not shorted.
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#define SERVO_PWM_MODE 1 // Normal 8 channel servo (pwm) input
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#define PPM_PASSTROUGH_MODE 2 // PPM signal passtrough on channel 1
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#define JETI_MODE 3 // Reserved
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#define SPEKTRUM_MODE 4 // Reserved for Spektrum satelitte on channel 1
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// Servo input mode (jumper (default), pwm, ppm, jeti or spektrum)
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volatile uint8_t servo_input_mode = JUMPER_SELECT_MODE;
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// -------------------------------------------------------------
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// Number of Timer1 ticks in one microsecond
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#define ONE_US F_CPU / 8 / 1000 / 1000
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// 400us PPM pre pulse
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#define PPM_PRE_PULSE ONE_US * 400
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// -------------------------------------------------------------
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// SERVO LIMIT VALUES
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// -------------------------------------------------------------
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// Servo minimum position
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#define PPM_SERVO_MIN ONE_US * 900 - PPM_PRE_PULSE
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// Servo center position
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#define PPM_SERVO_CENTER ONE_US * 1500 - PPM_PRE_PULSE
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// Servo maximum position
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#define PPM_SERVO_MAX ONE_US * 2100 - PPM_PRE_PULSE
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// Throttle default at power on
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#define PPM_THROTTLE_DEFAULT ONE_US * 1100 - PPM_PRE_PULSE
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// Throttle during failsafe
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#define PPM_THROTTLE_FAILSAFE ONE_US * 900 - PPM_PRE_PULSE
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// CH5 power on values (mode selection channel)
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#define PPM_CH5_MODE_4 ONE_US * 1555 - PPM_PRE_PULSE
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// -------------------------------------------------------------
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// PPM OUTPUT SETTINGS
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// -------------------------------------------------------------
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// #define _POSITIVE_PPM_FRAME_ // Switch to positive pulse PPM
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// (the actual timing is encoded in the length of the low between two pulses)
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// Number of servo input channels
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#define SERVO_CHANNELS 8
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// PPM period 18.5ms - 26.5ms (54hz - 37Hz)
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#define PPM_PERIOD ONE_US * ( 22500 - ( 8 * 1500 ) )
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// Size of ppm[..] data array ( servo channels * 2 + 2)
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#define PPM_ARRAY_MAX 18
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// -------------------------------------------------------------
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// SERVO FAILSAFE VALUES
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// -------------------------------------------------------------
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const uint16_t failsafe_ppm[ PPM_ARRAY_MAX ] =
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{
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PPM_PRE_PULSE,
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PPM_SERVO_CENTER, // Channel 1
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PPM_PRE_PULSE,
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PPM_SERVO_CENTER, // Channel 2
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PPM_PRE_PULSE,
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PPM_THROTTLE_FAILSAFE, // Channel 3 (throttle)
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PPM_PRE_PULSE,
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PPM_SERVO_CENTER, // Channel 4
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PPM_PRE_PULSE,
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PPM_CH5_MODE_4, // Channel 5
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PPM_PRE_PULSE,
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PPM_SERVO_CENTER, // Channel 6
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PPM_PRE_PULSE,
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PPM_SERVO_CENTER, // Channel 7
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PPM_PRE_PULSE,
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PPM_SERVO_CENTER, // Channel 8
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PPM_PRE_PULSE,
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PPM_PERIOD
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};
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// -------------------------------------------------------------
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// Data array for storing ppm (8 channels) pulse widths.
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// -------------------------------------------------------------
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volatile uint16_t ppm[ PPM_ARRAY_MAX ] =
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{
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PPM_PRE_PULSE,
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PPM_SERVO_CENTER, // Channel 1
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PPM_PRE_PULSE,
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PPM_SERVO_CENTER, // Channel 2
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PPM_PRE_PULSE,
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PPM_THROTTLE_DEFAULT, // Channel 3 (throttle)
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PPM_PRE_PULSE,
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PPM_SERVO_CENTER, // Channel 4
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PPM_PRE_PULSE,
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PPM_CH5_MODE_4, // Channel 5
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PPM_PRE_PULSE,
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PPM_SERVO_CENTER, // Channel 6
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PPM_PRE_PULSE,
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PPM_SERVO_CENTER, // Channel 7
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PPM_PRE_PULSE,
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PPM_SERVO_CENTER, // Channel 8
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PPM_PRE_PULSE,
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PPM_PERIOD
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};
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// -------------------------------------------------------------
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// Data arraw for storing ppm timeout (missing channel detection)
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// -------------------------------------------------------------
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#define PPM_TIMEOUT_VALUE 40 // ~1sec before triggering missing channel detection
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volatile uint8_t ppm_timeout[ PPM_ARRAY_MAX ];
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// Servo input channel connected flag
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volatile bool servo_input_connected[ PPM_ARRAY_MAX ];
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// AVR parameters for PhoneDrone and APM2 boards using ATmega32u2
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#if defined (__AVR_ATmega16U2__) || defined (__AVR_ATmega32U2__)
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#define SERVO_DDR DDRB
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#define SERVO_PORT PORTB
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#define SERVO_INPUT PINB
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#define SERVO_INT_VECTOR PCINT0_vect
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#define SERVO_INT_MASK PCMSK0
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#define SERVO_INT_CLEAR_FLAG PCIF0
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#define SERVO_INT_ENABLE PCIE0
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#define SERVO_TIMER_CNT TCNT1
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#define PPM_DDR DDRC
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#define PPM_PORT PORTC
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#define PPM_OUTPUT_PIN PC6
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#define PPM_INT_VECTOR TIMER1_COMPA_vect
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#define PPM_COMPARE OCR1A
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#define PPM_COMPARE_FLAG COM1A0
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#define PPM_COMPARE_ENABLE OCIE1A
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#define PPM_COMPARE_FORCE_MATCH FOC1A
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#define USB_DDR DDRC
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#define USB_PORT PORTC
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#define USB_PIN PC2
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// true if we have received a USB device connect event
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static bool usb_connected;
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// USB connected event
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void EVENT_USB_Device_Connect(void)
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{
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// Toggle USB pin high if USB is connected
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USB_PORT |= (1 << USB_PIN);
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usb_connected = true;
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// this unsets the pin connected to PA1 on the 2560
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// when the bit is clear, USB is connected
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PORTD &= ~1;
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}
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// USB disconnect event
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void EVENT_USB_Device_Disconnect(void)
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{
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// toggle USB pin low if USB is disconnected
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USB_PORT &= ~(1 << USB_PIN);
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usb_connected = false;
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// this sets the pin connected to PA1 on the 2560
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// when the bit is clear, USB is connected
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PORTD |= 1;
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}
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// AVR parameters for ArduPilot MEGA v1.4 PPM Encoder (ATmega328P)
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#elif defined (__AVR_ATmega328P__) || defined (__AVR_ATmega328__)
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#define SERVO_DDR DDRD
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#define SERVO_PORT PORTD
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#define SERVO_INPUT PIND
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#define SERVO_INT_VECTOR PCINT2_vect
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#define SERVO_INT_MASK PCMSK2
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#define SERVO_INT_CLEAR_FLAG PCIF2
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#define SERVO_INT_ENABLE PCIE2
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#define SERVO_TIMER_CNT TCNT1
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#define PPM_DDR DDRB
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#define PPM_PORT PORTB
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#define PPM_OUTPUT_PIN PB2
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#define PPM_INT_VECTOR TIMER1_COMPB_vect
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#define PPM_COMPARE OCR1B
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#define PPM_COMPARE_FLAG COM1B0
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#define PPM_COMPARE_ENABLE OCIE1B
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#define PPM_COMPARE_FORCE_MATCH FOC1B
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#else
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#error NO SUPPORTED DEVICE FOUND! (ATmega16u2 / ATmega32u2 / ATmega328p)
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#endif
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// Used to force throttle fail-safe mode (RTL)
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volatile bool throttle_failsafe_force = false;
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// Used to indicate invalid SERVO input signals
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volatile uint8_t servo_input_errors = 0;
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// Used to indicate missing SERVO input signals
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volatile bool servo_input_missing = true;
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// Used to indicate if PPM generator is active
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volatile bool ppm_generator_active = false;
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// Used to indicate a brownout restart
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volatile bool brownout_reset = false;
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// ------------------------------------------------------------------------------
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// PPM GENERATOR START - TOGGLE ON COMPARE INTERRUPT ENABLE
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// ------------------------------------------------------------------------------
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void ppm_start( void )
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{
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// Prevent reenabling an already active PPM generator
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if( ppm_generator_active ) return;
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// Store interrupt status and register flags
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uint8_t SREG_tmp = SREG;
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// Stop interrupts
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cli();
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// Make sure initial output state is low
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PPM_PORT &= ~(1 << PPM_OUTPUT_PIN);
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// Wait for output pin to settle
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//_delay_us( 1 );
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// Set initial compare toggle to maximum (32ms) to give other parts of the system time to start
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SERVO_TIMER_CNT = 0;
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PPM_COMPARE = 0xFFFF;
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// Set toggle on compare output
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TCCR1A = (1 << PPM_COMPARE_FLAG);
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// Set TIMER1 8x prescaler
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TCCR1B = ( 1 << CS11 );
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#if defined (_POSITIVE_PPM_FRAME_)
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// Force output compare to reverse polarity
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TCCR1C |= (1 << PPM_COMPARE_FORCE_MATCH);
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#endif
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// Enable output compare interrupt
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TIMSK1 |= (1 << PPM_COMPARE_ENABLE);
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// Indicate that PPM generator is active
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ppm_generator_active = true;
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// Restore interrupt status and register flags
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SREG = SREG_tmp;
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#if defined (__AVR_ATmega16U2__) || defined (__AVR_ATmega32U2__)
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// Turn on TX led if PPM generator is active
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PORTD &= ~( 1<< PD5 );
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#endif
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}
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// ------------------------------------------------------------------------------
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// PPM GENERATOR STOP - TOGGLE ON COMPARE INTERRUPT DISABLE
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// ------------------------------------------------------------------------------
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void ppm_stop( void )
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{
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// Store interrupt status and register flags
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uint8_t SREG_tmp = SREG;
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// Stop interrupts
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cli();
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// Disable output compare interrupt
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TIMSK1 &= ~(1 << PPM_COMPARE_ENABLE);
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// Reset TIMER1 registers
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TCCR1A = 0;
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TCCR1B = 0;
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// Indicate that PPM generator is not active
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ppm_generator_active = false;
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// Restore interrupt status and register flags
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SREG = SREG_tmp;
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#if defined (__AVR_ATmega16U2__) || defined (__AVR_ATmega32U2__)
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// Turn off TX led if PPM generator is off
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PORTD |= ( 1<< PD5 );
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#endif
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}
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// ------------------------------------------------------------------------------
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// Watchdog Interrupt (interrupt only mode, no reset)
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// ------------------------------------------------------------------------------
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ISR( WDT_vect ) // If watchdog is triggered then enable missing signal flag and copy power on or failsafe positions
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{
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// Use failsafe values if PPM generator is active or if chip has been reset from a brown-out
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if ( ppm_generator_active || brownout_reset )
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{
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// Copy failsafe values to ppm[..]
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for ( uint8_t i = 0; i < PPM_ARRAY_MAX; i++ )
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{
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ppm[ i ] = failsafe_ppm[ i ];
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}
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}
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// If we are in PPM passtrough mode and a input signal has been detected, or if chip has been reset from a brown_out then start the PPM generator.
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if( ( servo_input_mode == PPM_PASSTROUGH_MODE && servo_input_missing == false ) || brownout_reset )
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{
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// Start PPM generator
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ppm_start();
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brownout_reset = false;
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}
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// Set missing receiver signal flag
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servo_input_missing = true;
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// Reset servo input error flag
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servo_input_errors = 0;
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#if defined (__AVR_ATmega16U2__) || defined (__AVR_ATmega32U2__)
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// Turn on RX led if failsafe has triggered after ppm generator i active
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if( ppm_generator_active ) PORTD &= ~( 1<< PD4 );
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#endif
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}
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// ------------------------------------------------------------------------------
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// ------------------------------------------------------------------------------
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// SERVO/PPM INPUT - PIN CHANGE INTERRUPT
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// ------------------------------------------------------------------------------
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ISR( SERVO_INT_VECTOR )
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{
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// Servo pulse start timing
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//static uint16_t servo_start[ SERVO_CHANNELS ] = { 0, 0, 0, 0, 0, 0, 0, 0 };
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static uint16_t servo_start[ PPM_ARRAY_MAX ] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; // We sacrefice some memory but save instructions by working with ppm index count (18) instead of input channel count (8)
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#if defined (__AVR_ATmega16U2__) || defined (__AVR_ATmega32U2__)
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// Toggle LED delay
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static uint8_t led_delay = 0;
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#endif
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// Servo input pin storage
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static uint8_t servo_pins_old = 0;
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// Used to store current servo input pins
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uint8_t servo_pins;
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// Read current servo pulse change time
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uint16_t servo_time = SERVO_TIMER_CNT;
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// ------------------------------------------------------------------------------
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// PPM passtrough mode ( signal passtrough from channel 1 to ppm output pin)
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// ------------------------------------------------------------------------------
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if( servo_input_mode == PPM_PASSTROUGH_MODE )
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{
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// Has watchdog timer failsafe started PPM generator? If so we need to stop it.
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if( ppm_generator_active )
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{
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// Stop PPM generator
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ppm_stop();
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}
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// PPM (channel 1) input pin is high
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if( SERVO_INPUT & 1 )
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{
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// Set PPM output pin high
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PPM_PORT |= (1 << PPM_OUTPUT_PIN);
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}
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// PPM (channel 1) input pin is low
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else
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{
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// Set PPM output pin low
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PPM_PORT &= ~(1 << PPM_OUTPUT_PIN);
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}
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// Reset Watchdog Timer
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wdt_reset();
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// Set servo input missing flag false to indicate that we have received servo input signals
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servo_input_missing = false;
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#if defined (__AVR_ATmega16U2__) || defined (__AVR_ATmega32U2__)
|
|
// Toggle TX LED at PPM passtrough
|
|
if( ++led_delay > 128 ) // Toggle every 128th pulse
|
|
{
|
|
// Toggle TX led
|
|
PIND |= ( 1<< PD5 );
|
|
led_delay = 0;
|
|
}
|
|
#endif
|
|
|
|
// Leave interrupt
|
|
return;
|
|
}
|
|
|
|
// ------------------------------------------------------------------------------
|
|
// SERVO PWM MODE
|
|
// ------------------------------------------------------------------------------
|
|
uint8_t servo_change;
|
|
uint8_t servo_pin ;
|
|
//uint8_t servo_channel ;
|
|
uint8_t ppm_channel;
|
|
|
|
CHECK_PINS_START: // Start of servo input check
|
|
|
|
// Store current servo input pins
|
|
servo_pins = SERVO_INPUT;
|
|
|
|
// Calculate servo input pin change mask
|
|
servo_change = servo_pins ^ servo_pins_old;
|
|
|
|
// Set initial servo pin, channel and ppm[..] index
|
|
servo_pin = 1;
|
|
//servo_channel = 0;
|
|
ppm_channel = 1;
|
|
|
|
CHECK_PINS_LOOP: // Input servo pin check loop
|
|
|
|
// Check for pin change on current servo channel
|
|
if( servo_change & servo_pin )
|
|
{
|
|
// High (raising edge)
|
|
if( servo_pins & servo_pin )
|
|
{
|
|
//servo_start[ servo_channel ] = servo_time;
|
|
servo_start[ ppm_channel ] = servo_time;
|
|
}
|
|
else
|
|
{
|
|
|
|
// Get servo pulse width
|
|
//uint16_t servo_width = servo_time - servo_start[ servo_channel ] - PPM_PRE_PULSE;
|
|
uint16_t servo_width = servo_time - servo_start[ ppm_channel ] - PPM_PRE_PULSE;
|
|
|
|
// Check that servo pulse signal is valid before sending to ppm encoder
|
|
if( servo_width > PPM_SERVO_MAX ) goto CHECK_PINS_ERROR;
|
|
if( servo_width < PPM_SERVO_MIN ) goto CHECK_PINS_ERROR;
|
|
|
|
// Reset Watchdog Timer
|
|
wdt_reset();
|
|
|
|
// Channel has received a valid signal, so it must be connected
|
|
// servo_input_connected [ ppm_channel ] = true; // Removed - Check performed during init
|
|
|
|
// Check for forced throttle fail-safe
|
|
if( throttle_failsafe_force && ppm_channel == 5 )
|
|
{
|
|
// Force throttle fail-safe
|
|
ppm_timeout[ ppm_channel ] = 255;
|
|
}
|
|
else
|
|
{
|
|
//Reset ppm single channel fail-safe timeout
|
|
ppm_timeout[ ppm_channel ] = 0;
|
|
}
|
|
|
|
#ifdef _AVERAGE_FILTER_
|
|
// Average filter to smooth input jitter
|
|
servo_width += ppm[ ppm_channel ];
|
|
servo_width >>= 1;
|
|
#endif
|
|
|
|
#ifdef _JITTER_FILTER_
|
|
// 0.5us cut filter to remove input jitter
|
|
int16_t ppm_tmp = ppm[ ppm_channel ] - servo_width;
|
|
if( ppm_tmp == 1 ) goto CHECK_PINS_NEXT;
|
|
if( ppm_tmp == -1 ) goto CHECK_PINS_NEXT;
|
|
#endif
|
|
|
|
// Update ppm[..]
|
|
ppm[ ppm_channel ] = servo_width;
|
|
}
|
|
}
|
|
|
|
CHECK_PINS_NEXT:
|
|
|
|
// Select next servo pin
|
|
servo_pin <<= 1;
|
|
|
|
// Select next servo channel
|
|
//servo_channel++;
|
|
|
|
// Select next ppm[..] index
|
|
ppm_channel += 2;
|
|
|
|
// Check channel and process if needed
|
|
//if( servo_channel < SERVO_CHANNELS ) goto CHECK_PINS_LOOP;
|
|
if( servo_pin ) goto CHECK_PINS_LOOP; // Bit shifts to zero when all pins have been checked
|
|
|
|
goto CHECK_PINS_DONE;
|
|
|
|
CHECK_PINS_ERROR:
|
|
|
|
// Used to indicate invalid servo input signals
|
|
servo_input_errors++;
|
|
|
|
#if defined (__AVR_ATmega16U2__) || defined (__AVR_ATmega32U2__)
|
|
// Delay LED toggle
|
|
led_delay = 0;
|
|
#endif
|
|
|
|
goto CHECK_PINS_NEXT;
|
|
|
|
// All servo input pins has now been processed
|
|
|
|
CHECK_PINS_DONE:
|
|
|
|
// Set servo input missing flag false to indicate that we have received servo input signals
|
|
servo_input_missing = false;
|
|
|
|
// Store current servo input pins for next check
|
|
servo_pins_old = servo_pins;
|
|
|
|
// Start PPM generator if not already running
|
|
if( ppm_generator_active == false ) ppm_start();
|
|
|
|
#if defined (__AVR_ATmega16U2__) || defined (__AVR_ATmega32U2__)
|
|
// Toggle RX LED when finished receiving servo pulses
|
|
if( ++led_delay > 64 ) // Toggle led every 64th time
|
|
{
|
|
PIND |= ( 1<< PD4 );
|
|
led_delay = 0;
|
|
}
|
|
#endif
|
|
|
|
//Has servo input changed while processing pins, if so we need to re-check pins
|
|
if( servo_pins != SERVO_INPUT ) goto CHECK_PINS_START;
|
|
|
|
// Clear interrupt event from already processed pin changes
|
|
PCIFR |= (1 << SERVO_INT_CLEAR_FLAG);
|
|
}
|
|
// ------------------------------------------------------------------------------
|
|
|
|
|
|
// ------------------------------------------------------------------------------
|
|
// PPM OUTPUT - TIMER1 COMPARE INTERRUPT
|
|
// ------------------------------------------------------------------------------
|
|
ISR( PPM_INT_VECTOR )
|
|
{
|
|
// Current active ppm channel
|
|
static uint8_t ppm_channel = PPM_ARRAY_MAX - 1;
|
|
|
|
// Update timing for next compare toggle with either current ppm input value, or fail-safe value if there is a channel timeout.
|
|
if( ppm_timeout[ ppm_channel ] > PPM_TIMEOUT_VALUE )
|
|
{
|
|
// Use ppm fail-safe value
|
|
PPM_COMPARE += failsafe_ppm[ ppm_channel ];
|
|
|
|
// Did we lose an active servo input channel? If so force throttle fail-safe (RTL)
|
|
if( servo_input_connected[ ppm_channel ] )
|
|
{
|
|
throttle_failsafe_force = true;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
// Use latest ppm input value
|
|
PPM_COMPARE += ppm[ ppm_channel ];
|
|
|
|
// Increment channel timeout (reset to zero in input interrupt each time a valid signal is detected)
|
|
ppm_timeout[ ppm_channel ] ++;
|
|
}
|
|
|
|
// Select the next ppm channel
|
|
if( ++ppm_channel >= PPM_ARRAY_MAX )
|
|
{
|
|
ppm_channel = 0;
|
|
|
|
#if defined (__AVR_ATmega16U2__) || defined (__AVR_ATmega32U2__)
|
|
// Blink TX LED when PPM generator has finished a pulse train
|
|
PIND |= ( 1<< PD5 );
|
|
#endif
|
|
}
|
|
}
|
|
// ------------------------------------------------------------------------------
|
|
|
|
// ------------------------------------------------------------------------------
|
|
// PPM READ - INTERRUPT SAFE PPM SERVO CHANNEL READ
|
|
// ------------------------------------------------------------------------------
|
|
uint16_t ppm_read_channel( uint8_t channel )
|
|
{
|
|
// Limit channel to valid value
|
|
uint8_t _channel = channel;
|
|
if( _channel == 0 ) _channel = 1;
|
|
if( _channel > SERVO_CHANNELS ) _channel = SERVO_CHANNELS;
|
|
|
|
// Calculate ppm[..] position
|
|
uint8_t ppm_index = ( _channel << 1 ) + 1;
|
|
|
|
// Read ppm[..] in a non blocking interrupt safe manner
|
|
uint16_t ppm_tmp = ppm[ ppm_index ];
|
|
while( ppm_tmp != ppm[ ppm_index ] ) ppm_tmp = ppm[ ppm_index ];
|
|
|
|
// Return as normal servo value
|
|
return ppm_tmp + PPM_PRE_PULSE;
|
|
}
|
|
// ------------------------------------------------------------------------------
|
|
|
|
// ------------------------------------------------------------------------------
|
|
// PPM ENCODER INIT
|
|
// ------------------------------------------------------------------------------
|
|
void ppm_encoder_init( void )
|
|
{
|
|
// ATmegaXXU2 only init code
|
|
// ------------------------------------------------------------------------------
|
|
#if defined (__AVR_ATmega16U2__) || defined (__AVR_ATmega32U2__)
|
|
// ------------------------------------------------------------------------------
|
|
// Reset Source checkings
|
|
// ------------------------------------------------------------------------------
|
|
if (MCUSR & 1) // Power-on Reset
|
|
{
|
|
MCUSR=0; // Clear MCU Status register
|
|
// custom code here
|
|
}
|
|
else if (MCUSR & 2) // External Reset
|
|
{
|
|
MCUSR=0; // Clear MCU Status register
|
|
// custom code here
|
|
}
|
|
else if (MCUSR & 4) // Brown-Out Reset
|
|
{
|
|
MCUSR=0; // Clear MCU Status register
|
|
brownout_reset=true;
|
|
}
|
|
else // Watchdog Reset
|
|
{
|
|
MCUSR=0; // Clear MCU Status register
|
|
// custom code here
|
|
}
|
|
|
|
// APM USB connection status UART MUX selector pin
|
|
// ------------------------------------------------------------------------------
|
|
USB_DDR |= (1 << USB_PIN); // Set USB pin to output
|
|
#endif
|
|
|
|
|
|
// USE JUMPER TO CHECK FOR PWM OR PPM PASSTROUGH MODE (channel 2&3 shorted)
|
|
// ------------------------------------------------------------------------------
|
|
if( servo_input_mode == JUMPER_SELECT_MODE )
|
|
{
|
|
// channel 3 status counter
|
|
uint8_t channel3_status = 0;
|
|
|
|
// Set channel 3 to input
|
|
SERVO_DDR &= ~(1 << 2);
|
|
|
|
// Enable channel 3 pullup
|
|
SERVO_PORT |= (1 << 2);
|
|
|
|
// Set channel 2 to output
|
|
SERVO_DDR |= (1 << 1);
|
|
|
|
// Set channel 2 output low
|
|
SERVO_PORT &= ~(1 << 1);
|
|
|
|
_delay_us (10);
|
|
|
|
// Increment channel3_status if channel 3 is set low by channel 2
|
|
if( ( SERVO_INPUT & (1 << 2) ) == 0 ) channel3_status++;
|
|
|
|
// Set channel 2 output high
|
|
SERVO_PORT |= (1 << 1);
|
|
|
|
_delay_us (10);
|
|
|
|
// Increment channel3_status if channel 3 is set high by channel 2
|
|
if( ( SERVO_INPUT & (1 << 2) ) != 0 ) channel3_status++;
|
|
|
|
// Set channel 2 output low
|
|
SERVO_PORT &= ~(1 << 1);
|
|
|
|
_delay_us (10);
|
|
|
|
// Increment channel3_status if channel 3 is set low by channel 2
|
|
if( ( SERVO_INPUT & (1 << 2) ) == 0 ) channel3_status++;
|
|
|
|
// Set servo input mode based on channel3_status
|
|
if( channel3_status == 3 ) servo_input_mode = PPM_PASSTROUGH_MODE;
|
|
else servo_input_mode = SERVO_PWM_MODE;
|
|
|
|
}
|
|
|
|
|
|
// SERVO/PPM INPUT PINS
|
|
// ------------------------------------------------------------------------------
|
|
// Set all servo input pins to inputs
|
|
SERVO_DDR = 0;
|
|
|
|
// Activate pullups on all input pins
|
|
SERVO_PORT |= 0xFF;
|
|
|
|
#if defined (__AVR_ATmega16U2__) || defined (__AVR_ATmega32U2__)
|
|
// on 32U2 set PD0 to be an output, and clear the bit. This tells
|
|
// the 2560 that USB is connected. The USB connection event fires
|
|
// later to set the right value
|
|
DDRD |= 1;
|
|
if (usb_connected) {
|
|
PORTD &= ~1;
|
|
} else {
|
|
PORTD |= 1;
|
|
}
|
|
#endif
|
|
|
|
// PPM PASS-THROUGH MODE
|
|
if( servo_input_mode == PPM_PASSTROUGH_MODE )
|
|
{
|
|
// Set servo input interrupt pin mask to servo input channel 1
|
|
SERVO_INT_MASK = 0x01;
|
|
}
|
|
|
|
// SERVO PWM INPUT MODE
|
|
// ------------------------------------------------------------------------------
|
|
if( servo_input_mode == SERVO_PWM_MODE )
|
|
{
|
|
// CHECK FOR ACTIVE INPUT CHANNELS
|
|
// ------------------------------------------------------------------------------
|
|
// This will poll the input pins looking for pin level changes, and mark the inputs with active signal connections
|
|
|
|
uint16_t input_channel_count[ SERVO_CHANNELS ];
|
|
uint8_t input_current; // Input pin level mask
|
|
uint8_t input_previous; // Input pin level mask
|
|
uint8_t input_int_mask; // Active input pin interupt mask
|
|
|
|
INPUT_ACTIVE_CHANNEL_CHECK:
|
|
|
|
// ~100khz timed polling of input pins for ~0.5sec duration (1us = 16 clocks)
|
|
for( uint16_t t = 0; t < 50000; t++ ) // 10us * 1000ms * 0.5sec = 50000 delayed loops at 10us
|
|
{
|
|
// Get current input pin levels
|
|
input_current = SERVO_INPUT;
|
|
|
|
// Check input pins against previous levels
|
|
uint8_t input_change = input_current ^ input_previous;
|
|
|
|
// Do we need to check for changes?
|
|
if( input_change )
|
|
{
|
|
// Check for change on all input pins
|
|
uint8_t input_pin = 1;
|
|
uint8_t input_channel = 0;
|
|
|
|
do
|
|
{
|
|
// Check for change on current input pin
|
|
if( input_change & input_pin )
|
|
{
|
|
// Pin has changed, count it
|
|
input_channel_count[ input_channel ]++;
|
|
}
|
|
|
|
// Select next pin
|
|
input_pin <<= 1;
|
|
|
|
// Select next channel
|
|
input_channel++;
|
|
|
|
} while ( input_channel < SERVO_CHANNELS );
|
|
|
|
// Store checked input pin levels
|
|
input_previous = input_current;
|
|
}
|
|
|
|
// Delay the next input level check
|
|
_delay_us( 10 );
|
|
|
|
}
|
|
|
|
// Check input_channel_count[..] to see if channels are active.
|
|
for( uint8_t input_channel = 0; input_channel < SERVO_CHANNELS; input_channel++ )
|
|
{
|
|
// Is current channel active?
|
|
if( input_channel_count[ input_channel ] > 20 ) // 0.5sec * 40hz * 2 = 40 pulse edges - 50% margin = 20 level changes
|
|
{
|
|
// Set active channel in servo_input_connected[..]
|
|
servo_input_connected[ (input_channel << 1) + 1 ] = true;
|
|
|
|
// Set interupt pin mask for active channel
|
|
input_int_mask |= 1 << input_channel;
|
|
|
|
}
|
|
}
|
|
|
|
// if no active input channels are found, then re-check until found (might be caused by delayed receiver startup)
|
|
// Do not perform re-check if there was a brown-out reset
|
|
if( input_int_mask == 0 && !brownout_reset )
|
|
{
|
|
// Re-check active input channels
|
|
goto INPUT_ACTIVE_CHANNEL_CHECK;
|
|
}
|
|
|
|
// Set servo input interrupt pin mask
|
|
// Set to all input channel for safety in case of brown-out reset
|
|
if( brownout_reset)
|
|
{
|
|
// Interrupt on all input pins
|
|
SERVO_INT_MASK = 0xFF;
|
|
}
|
|
else
|
|
{
|
|
// Interrupt only on active input pins
|
|
SERVO_INT_MASK = input_int_mask;
|
|
}
|
|
}
|
|
|
|
|
|
// Enable servo input interrupt
|
|
PCICR |= (1 << SERVO_INT_ENABLE);
|
|
|
|
// PPM OUTPUT
|
|
// ------------------------------------------------------------------------------
|
|
// PPM generator (PWM output timer/counter) is started either by pin change interrupt or by watchdog interrupt
|
|
|
|
// Set PPM pin to output
|
|
PPM_DDR |= (1 << PPM_OUTPUT_PIN);
|
|
|
|
|
|
// ------------------------------------------------------------------------------
|
|
// Enable watchdog interrupt mode
|
|
// ------------------------------------------------------------------------------
|
|
// Disable watchdog
|
|
wdt_disable();
|
|
// Reset watchdog timer
|
|
wdt_reset();
|
|
// Start timed watchdog setup sequence
|
|
WDTCSR |= (1<<WDCE) | (1<<WDE );
|
|
// Set 250 ms watchdog timeout and enable interrupt
|
|
WDTCSR = (1<<WDIE) | (1<<WDP2);
|
|
|
|
|
|
|
|
}
|
|
// ------------------------------------------------------------------------------
|
|
|
|
#endif // _PPM_ENCODER_H_
|
|
|