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958 lines
32 KiB
958 lines
32 KiB
// !!!!!!!!!! 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__) |
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// Toggle TX LED at PPM passtrough |
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if( ++led_delay > 128 ) // Toggle every 128th pulse |
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{ |
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// Toggle TX led |
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PIND |= ( 1<< PD5 ); |
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led_delay = 0; |
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} |
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#endif |
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// Leave interrupt |
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return; |
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} |
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// ------------------------------------------------------------------------------ |
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// SERVO PWM MODE |
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// ------------------------------------------------------------------------------ |
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uint8_t servo_change; |
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uint8_t servo_pin ; |
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//uint8_t servo_channel ; |
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uint8_t ppm_channel; |
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CHECK_PINS_START: // Start of servo input check |
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// Store current servo input pins |
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servo_pins = SERVO_INPUT; |
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// Calculate servo input pin change mask |
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servo_change = servo_pins ^ servo_pins_old; |
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// Set initial servo pin, channel and ppm[..] index |
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servo_pin = 1; |
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//servo_channel = 0; |
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ppm_channel = 1; |
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CHECK_PINS_LOOP: // Input servo pin check loop |
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// Check for pin change on current servo channel |
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if( servo_change & servo_pin ) |
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{ |
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// High (raising edge) |
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if( servo_pins & servo_pin ) |
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{ |
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//servo_start[ servo_channel ] = servo_time; |
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servo_start[ ppm_channel ] = servo_time; |
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} |
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else |
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{ |
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// Get servo pulse width |
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//uint16_t servo_width = servo_time - servo_start[ servo_channel ] - PPM_PRE_PULSE; |
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uint16_t servo_width = servo_time - servo_start[ ppm_channel ] - PPM_PRE_PULSE; |
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// Check that servo pulse signal is valid before sending to ppm encoder |
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if( servo_width > PPM_SERVO_MAX ) goto CHECK_PINS_ERROR; |
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if( servo_width < PPM_SERVO_MIN ) goto CHECK_PINS_ERROR; |
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// Reset Watchdog Timer |
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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_ |
|
|
|
|