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235 lines
7.8 KiB
235 lines
7.8 KiB
/* |
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SUMD decoder, based on PX4Firmware/src/rc/lib/rc/sumd.c from PX4Firmware |
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modified for use in AP_HAL_* by Andrew Tridgell |
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*/ |
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/**************************************************************************** |
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* |
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* Copyright (c) 2015 PX4 Development Team. All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* 3. Neither the name PX4 nor the names of its contributors may be |
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* used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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* POSSIBILITY OF SUCH DAMAGE. |
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* |
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****************************************************************************/ |
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/* |
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* @file sumd.h |
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* |
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* RC protocol definition for Graupner HoTT transmitter (SUMD/SUMH Protocol) |
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* |
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* @author Marco Bauer <marco@wtns.de> |
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*/ |
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#include "AP_RCProtocol_ST24.h" |
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// #define SUMD_DEBUG |
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extern const AP_HAL::HAL& hal; |
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uint8_t AP_RCProtocol_ST24::st24_crc8(uint8_t *ptr, uint8_t len) |
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{ |
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uint8_t i, crc ; |
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crc = 0; |
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while (len--) { |
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for (i = 0x80; i != 0; i >>= 1) { |
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if ((crc & 0x80) != 0) { |
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crc <<= 1; |
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crc ^= 0x07; |
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} else { |
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crc <<= 1; |
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} |
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if ((*ptr & i) != 0) { |
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crc ^= 0x07; |
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} |
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} |
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ptr++; |
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} |
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return (crc); |
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} |
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void AP_RCProtocol_ST24::process_pulse(uint32_t width_s0, uint32_t width_s1) |
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{ |
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uint8_t b; |
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if (ss.process_pulse(width_s0, width_s1, b)) { |
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_process_byte(b); |
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} |
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} |
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void AP_RCProtocol_ST24::_process_byte(uint8_t byte) |
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{ |
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switch (_decode_state) { |
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case ST24_DECODE_STATE_UNSYNCED: |
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if (byte == ST24_STX1) { |
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_decode_state = ST24_DECODE_STATE_GOT_STX1; |
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} |
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break; |
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case ST24_DECODE_STATE_GOT_STX1: |
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if (byte == ST24_STX2) { |
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_decode_state = ST24_DECODE_STATE_GOT_STX2; |
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} else { |
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_decode_state = ST24_DECODE_STATE_UNSYNCED; |
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} |
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break; |
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case ST24_DECODE_STATE_GOT_STX2: |
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/* ensure no data overflow failure or hack is possible */ |
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if (byte > 8 && (unsigned)byte <= sizeof(_rxpacket.length) + sizeof(_rxpacket.type) + sizeof(_rxpacket.st24_data)) { |
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_rxpacket.length = byte; |
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_rxlen = 0; |
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_decode_state = ST24_DECODE_STATE_GOT_LEN; |
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} else { |
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_decode_state = ST24_DECODE_STATE_UNSYNCED; |
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} |
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break; |
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case ST24_DECODE_STATE_GOT_LEN: |
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_rxpacket.type = byte; |
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_rxlen++; |
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_decode_state = ST24_DECODE_STATE_GOT_TYPE; |
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break; |
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case ST24_DECODE_STATE_GOT_TYPE: |
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_rxpacket.st24_data[_rxlen - 1] = byte; |
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_rxlen++; |
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if (_rxlen == (_rxpacket.length - 1)) { |
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_decode_state = ST24_DECODE_STATE_GOT_DATA; |
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} |
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break; |
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case ST24_DECODE_STATE_GOT_DATA: |
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_rxpacket.crc8 = byte; |
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_rxlen++; |
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log_data(AP_RCProtocol::ST24, AP_HAL::micros(), (const uint8_t *)&_rxpacket, _rxlen+3); |
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if (st24_crc8((uint8_t *) & (_rxpacket.length), _rxlen) == _rxpacket.crc8) { |
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/* decode the actual packet */ |
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switch (_rxpacket.type) { |
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case ST24_PACKET_TYPE_CHANNELDATA12: { |
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uint16_t values[12]; |
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uint8_t num_values; |
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ChannelData12 *d = (ChannelData12 *)_rxpacket.st24_data; |
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//TBD: add support for RSSI |
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// *rssi = d->rssi; |
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//*rx_count = d->packet_count; |
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/* this can lead to rounding of the strides */ |
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num_values = (MAX_RCIN_CHANNELS < 12) ? MAX_RCIN_CHANNELS : 12; |
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unsigned stride_count = (num_values * 3) / 2; |
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unsigned chan_index = 0; |
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for (unsigned i = 0; i < stride_count; i += 3) { |
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values[chan_index] = ((uint16_t)d->channel[i] << 4); |
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values[chan_index] |= ((uint16_t)(0xF0 & d->channel[i + 1]) >> 4); |
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/* convert values to 1000-2000 ppm encoding in a not too sloppy fashion */ |
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values[chan_index] = (uint16_t)(values[chan_index] * ST24_SCALE_FACTOR + .5f) + ST24_SCALE_OFFSET; |
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chan_index++; |
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values[chan_index] = ((uint16_t)d->channel[i + 2]); |
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values[chan_index] |= (((uint16_t)(0x0F & d->channel[i + 1])) << 8); |
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/* convert values to 1000-2000 ppm encoding in a not too sloppy fashion */ |
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values[chan_index] = (uint16_t)(values[chan_index] * ST24_SCALE_FACTOR + .5f) + ST24_SCALE_OFFSET; |
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chan_index++; |
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} |
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} |
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break; |
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case ST24_PACKET_TYPE_CHANNELDATA24: { |
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uint16_t values[24]; |
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uint8_t num_values; |
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ChannelData24 *d = (ChannelData24 *)&_rxpacket.st24_data; |
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//*rssi = d->rssi; |
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//*rx_count = d->packet_count; |
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/* this can lead to rounding of the strides */ |
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num_values = (MAX_RCIN_CHANNELS < 24) ? MAX_RCIN_CHANNELS : 24; |
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unsigned stride_count = (num_values * 3) / 2; |
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unsigned chan_index = 0; |
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for (unsigned i = 0; i < stride_count; i += 3) { |
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values[chan_index] = ((uint16_t)d->channel[i] << 4); |
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values[chan_index] |= ((uint16_t)(0xF0 & d->channel[i + 1]) >> 4); |
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/* convert values to 1000-2000 ppm encoding in a not too sloppy fashion */ |
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values[chan_index] = (uint16_t)(values[chan_index] * ST24_SCALE_FACTOR + .5f) + ST24_SCALE_OFFSET; |
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chan_index++; |
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values[chan_index] = ((uint16_t)d->channel[i + 2]); |
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values[chan_index] |= (((uint16_t)(0x0F & d->channel[i + 1])) << 8); |
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/* convert values to 1000-2000 ppm encoding in a not too sloppy fashion */ |
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values[chan_index] = (uint16_t)(values[chan_index] * ST24_SCALE_FACTOR + .5f) + ST24_SCALE_OFFSET; |
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chan_index++; |
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} |
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} |
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break; |
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case ST24_PACKET_TYPE_TRANSMITTERGPSDATA: { |
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// ReceiverFcPacket* d = (ReceiverFcPacket*)&_rxpacket.st24_data; |
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/* we silently ignore this data for now, as it is unused */ |
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} |
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break; |
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default: |
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break; |
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} |
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} else { |
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/* decoding failed */ |
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} |
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_decode_state = ST24_DECODE_STATE_UNSYNCED; |
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break; |
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} |
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} |
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void AP_RCProtocol_ST24::process_byte(uint8_t byte, uint32_t baudrate) |
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{ |
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if (baudrate != 115200) { |
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return; |
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} |
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_process_byte(byte); |
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}
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