Files
edgetx-gx12/radio/src/pulses/crossfire.cpp
T

63 lines
2.0 KiB
C++

/*
* Copyright (C) OpenTX
*
* Based on code named
* th9x - http://code.google.com/p/th9x
* er9x - http://code.google.com/p/er9x
* gruvin9x - http://code.google.com/p/gruvin9x
*
* License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
*
* 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 CROSSFIRE_CH_CENTER 0x3E0
#define CROSSFIRE_CH_BITS 11
// Range for pulses (channels output) is [-1024:+1024]
uint8_t createCrossfireFrame(uint8_t * frame, int16_t * pulses, LuaTelemetryPacket * telemetryPacket)
{
uint8_t * buf = frame;
*buf++ = MODULE_ADDRESS;
if (telemetryPacket->crossfire.command) {
*buf++ = 2 + telemetryPacket->crossfire.length; // 1(ID) + telemetryPacket->crossfire.length + 1(CRC)
uint8_t * crc_start = buf;
*buf++ = telemetryPacket->crossfire.command;
for (int i=0; i<telemetryPacket->crossfire.length; i++) {
*buf++ = telemetryPacket->crossfire.data[i];
}
*buf++ = crc8(crc_start, telemetryPacket->crossfire.length + 1);
telemetryPacket->crossfire.clear();
}
else {
*buf++ = 24; // 1(ID) + 22 + 1(CRC)
uint8_t * crc_start = buf;
*buf++ = CHANNELS_ID;
uint32_t bits = 0;
uint8_t bitsavailable = 0;
for (int i=0; i<CROSSFIRE_CHANNELS_COUNT; i++) {
uint32_t val = limit(0, CROSSFIRE_CH_CENTER + (((pulses[i]) * 4) / 5), 2*CROSSFIRE_CH_CENTER);
bits |= val << bitsavailable;
bitsavailable += CROSSFIRE_CH_BITS;
while (bitsavailable >= 8) {
*buf++ = bits;
bits >>= 8;
bitsavailable -= 8;
}
}
*buf++ = crc8(crc_start, 23);
}
return buf - frame;
}