Files
edgetx-gx12/radio/src/sbus.cpp
T

105 lines
2.5 KiB
C++

/*
* Authors (alphabetical order)
* - Andre Bernet <bernet.andre@gmail.com>
* - Andreas Weitl
* - Bertrand Songis <bsongis@gmail.com>
* - Bryan J. Rentoul (Gruvin) <gruvin@gmail.com>
* - Cameron Weeks <th9xer@gmail.com>
* - Erez Raviv
* - Gabriel Birkus
* - Jean-Pierre Parisy
* - Karl Szmutny
* - Michael Blandford
* - Michal Hlavinka
* - Pat Mackenzie
* - Philip Moss
* - Rob Thomson
* - Romolo Manfredini <romolo.manfredini@gmail.com>
* - Thomas Husterer
*
* opentx is based on code named
* gruvin9x by Bryan J. Rentoul: http://code.google.com/p/gruvin9x/,
* er9x by Erez Raviv: http://code.google.com/p/er9x/,
* and the original (and ongoing) project by
* Thomas Husterer, th9x: http://code.google.com/p/th9x/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include "opentx.h"
#define SBUS_FLAGS_IDX 23
#define SBUS_FRAMELOST_BIT 2
#define SBUS_FAILSAFE_BIT 3
Fifo<32> sbusFifo;
uint8_t SbusFrame[28] ;
uint16_t SbusTimer ;
uint8_t SbusIndex = 0 ;
void processSbusFrame(uint8_t *sbus, int16_t *pulses, uint32_t size)
{
uint32_t inputbitsavailable = 0;
uint32_t inputbits = 0;
if (*sbus++ != 0x0F) {
return; // not a valid SBUS frame
}
if (size < 23) {
return;
}
if (size > SBUS_FLAGS_IDX &&
(sbus[SBUS_FLAGS_IDX-1] & (1<<SBUS_FAILSAFE_BIT))) {
return; // SBUS failsafe mode
}
for (uint32_t i=0; i<NUM_TRAINER; i++) {
while (inputbitsavailable < 11) {
inputbits |= *sbus++ << inputbitsavailable;
inputbitsavailable += 8;
}
*pulses++ = ((int32_t) (inputbits & 0x7FF) - 0x3E0) * 5 / 8;
inputbitsavailable -= 11;
inputbits >>= 11;
}
ppmInValid = PPM_IN_VALID_TIMEOUT;
}
#define SBUS_DELAY 1000 // 500uS
void processSbusInput()
{
uint8_t rxchar;
uint32_t active = 0;
while (sbusFifo.pop(rxchar)) {
active = 1;
SbusFrame[SbusIndex++] = rxchar;
if (SbusIndex > 27) {
SbusIndex = 27;
}
}
if (active) {
SbusTimer = getTmr2MHz();
return;
}
else {
if (SbusIndex) {
if ((uint16_t) (getTmr2MHz() - SbusTimer) > SBUS_DELAY) {
processSbusFrame(SbusFrame, g_ppmIns, SbusIndex);
SbusIndex = 0;
}
}
}
}