47 lines
1.4 KiB
C++
47 lines
1.4 KiB
C++
/*
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* Copyright (C) OpenTX
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*
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* Based on code named
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* th9x - http://code.google.com/p/th9x
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* er9x - http://code.google.com/p/er9x
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* gruvin9x - http://code.google.com/p/gruvin9x
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*
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* License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
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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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#include "opentx.h"
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#define CROSSFIRE_CH_CENTER 0x3E0
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#define CROSSFIRE_CH_BITS 11
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// Range for pulses (channels output) is [-1024:+1024]
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void createCrossfireFrame(uint8_t * frame, int16_t * pulses)
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{
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uint8_t * buf = frame;
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*buf++ = BROADCAST_ADDRESS;
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*buf++ = 24; // 1(ID) + 22 + 1(CRC)
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*buf++ = CHANNELS_ID;
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uint32_t bits = 0;
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uint8_t bitsavailable = 0;
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for (int i=0; i<CROSSFIRE_CHANNELS_COUNT; i++) {
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bits |= (CROSSFIRE_CH_CENTER + (((pulses[i]) * 4) / 5)) << bitsavailable;
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bitsavailable += CROSSFIRE_CH_BITS;
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while (bitsavailable >= 8) {
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*buf++ = bits;
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bits >>= 8;
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bitsavailable -= 8;
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}
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}
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*buf = crc8(&frame[2], 23);
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}
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