116 lines
3.0 KiB
C++
116 lines
3.0 KiB
C++
/*
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* Authors (alphabetical order)
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* - Andre Bernet <bernet.andre@gmail.com>
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* - Andreas Weitl
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* - Bertrand Songis <bsongis@gmail.com>
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* - Bryan J. Rentoul (Gruvin) <gruvin@gmail.com>
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* - Cameron Weeks <th9xer@gmail.com>
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* - Erez Raviv
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* - Gabriel Birkus
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* - Jean-Pierre Parisy
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* - Karl Szmutny
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* - Michael Blandford
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* - Michal Hlavinka
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* - Pat Mackenzie
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* - Philip Moss
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* - Rob Thomson
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* - Romolo Manfredini <romolo.manfredini@gmail.com>
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* - Thomas Husterer
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*
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* opentx is based on code named
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* gruvin9x by Bryan J. Rentoul: http://code.google.com/p/gruvin9x/,
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* er9x by Erez Raviv: http://code.google.com/p/er9x/,
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* and the original (and ongoing) project by
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* Thomas Husterer, th9x: http://code.google.com/p/th9x/
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include "opentx.h"
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#define SBUS_MIN_FRAME_SIZE 23
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#define SBUS_MAX_FRAME_SIZE 28
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#define SBUS_FRAME_GAP_DELAY 1000 // 500uS
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#define SBUS_START_BYTE 0x0F
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#define SBUS_FLAGS_IDX 23
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#define SBUS_FRAMELOST_BIT 2
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#define SBUS_FAILSAFE_BIT 3
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#define SBUS_CH_BITS 11
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#define SBUS_CH_MASK ((1<<SBUS_CH_BITS)-1)
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#define SBUS_CH_CENTER 0x3E0
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Fifo<32> sbusFifo;
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uint8_t SbusFrame[SBUS_MAX_FRAME_SIZE];
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uint16_t SbusTimer ;
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uint8_t SbusIndex = 0 ;
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void processSbusFrame(uint8_t *sbus, int16_t *pulses, uint32_t size)
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{
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uint32_t inputbitsavailable = 0;
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uint32_t inputbits = 0;
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if (sbus[0] != SBUS_START_BYTE) {
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return; // not a valid SBUS frame
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}
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if (size < SBUS_MIN_FRAME_SIZE) {
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return;
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}
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if (size > SBUS_FLAGS_IDX && ((sbus[SBUS_FLAGS_IDX] & (1<<SBUS_FAILSAFE_BIT)) || (sbus[SBUS_FLAGS_IDX] & (1<<SBUS_FRAMELOST_BIT)))) {
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return; // SBUS invalid frame or failsafe mode
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}
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// Skip start byte
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sbus++;
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for (uint32_t i=0; i<NUM_TRAINER; i++) {
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while (inputbitsavailable < SBUS_CH_BITS) {
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inputbits |= *sbus++ << inputbitsavailable;
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inputbitsavailable += 8;
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}
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*pulses++ = ((int32_t) (inputbits & SBUS_CH_MASK) - SBUS_CH_CENTER) * 5 / 8;
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inputbitsavailable -= SBUS_CH_BITS;
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inputbits >>= SBUS_CH_BITS;
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}
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ppmInputValidityTimer = PPM_IN_VALID_TIMEOUT;
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}
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void processSbusInput()
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{
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uint8_t rxchar;
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uint32_t active = 0;
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while (sbusFifo.pop(rxchar)) {
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active = 1;
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SbusFrame[SbusIndex++] = rxchar;
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if (SbusIndex > SBUS_MAX_FRAME_SIZE-1) {
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SbusIndex = SBUS_MAX_FRAME_SIZE-1;
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}
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}
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if (active) {
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SbusTimer = getTmr2MHz();
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return;
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}
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else {
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if (SbusIndex) {
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if ((uint16_t) (getTmr2MHz() - SbusTimer) > SBUS_FRAME_GAP_DELAY) {
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processSbusFrame(SbusFrame, ppmInput, SbusIndex);
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SbusIndex = 0;
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}
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}
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}
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}
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