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66 lines
3.8 KiB
66 lines
3.8 KiB
/* |
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* This file is free software: you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License as published by the |
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* Free Software Foundation, either version 3 of the License, or |
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* (at your option) any later version. |
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* |
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* This file is distributed in the hope that it will be useful, but |
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* WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. |
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* See the GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License along |
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* with this program. If not, see <http://www.gnu.org/licenses/>. |
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* |
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* Code by Andrew Tridgell and Siddharth Bharat Purohit |
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*/ |
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#pragma once |
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#include "AP_RCProtocol.h" |
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#include "SoftSerial.h" |
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#define SRXL_MIN_FRAMESPACE_US 8000U /* Minumum space between srxl frames in us (applies to all variants) */ |
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#define SRXL_MAX_CHANNELS 20U /* Maximum number of channels from srxl datastream */ |
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/* Variant specific SRXL datastream characteristics */ |
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/* Framelength in byte */ |
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#define SRXL_FRAMELEN_V1 27U /* Framelength with header in byte for: Mpx SRXLv1 or XBUS Mode B */ |
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#define SRXL_FRAMELEN_V2 35U /* Framelength with header in byte for: Mpx SRXLv2 */ |
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#define SRXL_FRAMELEN_V5 18U /* Framelength with header in byte for Spk AR7700 etc. */ |
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#define SRXL_FRAMELEN_MAX 35U /* maximum possible framelengh */ |
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/* Headerbyte */ |
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#define SRXL_HEADER_V1 0xA1U /* Headerbyte for: Mpx SRXLv1 or XBUS Mode B */ |
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#define SRXL_HEADER_V2 0xA2U /* Headerbyte for: Mpx SRXLv2 */ |
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#define SRXL_HEADER_V5 0xA5U /* Headerbyte for: Spk AR7700 etc. */ |
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#define SRXL_HEADER_NOT_IMPL 0xFFU /* Headerbyte for non impemented srxl header*/ |
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class AP_RCProtocol_SRXL : public AP_RCProtocol_Backend { |
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public: |
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AP_RCProtocol_SRXL(AP_RCProtocol &_frontend) : AP_RCProtocol_Backend(_frontend) {} |
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void process_pulse(uint32_t width_s0, uint32_t width_s1) override; |
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void process_byte(uint8_t byte, uint32_t baudrate) override; |
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private: |
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void _process_byte(uint32_t timestamp_us, uint8_t byte); |
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int srxl_channels_get_v1v2(uint16_t max_values, uint8_t *num_values, uint16_t *values, bool *failsafe_state); |
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int srxl_channels_get_v5(uint16_t max_values, uint8_t *num_values, uint16_t *values, bool *failsafe_state); |
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uint8_t buffer[SRXL_FRAMELEN_MAX]; /* buffer for raw srxl frame data in correct order --> buffer[0]=byte0 buffer[1]=byte1 */ |
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uint8_t buflen; /* length in number of bytes of received srxl dataframe in buffer */ |
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uint32_t last_data_us; /* timespan since last received data in us */ |
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uint16_t channels[SRXL_MAX_CHANNELS] = {0}; /* buffer for extracted RC channel data as pulsewidth in microseconds */ |
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uint16_t max_channels = 0; |
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enum { |
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STATE_IDLE, /* do nothing */ |
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STATE_NEW, /* get header of frame + prepare for frame reception + begin new crc cycle */ |
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STATE_COLLECT /* collect RC channel data from frame + concurrently calc crc over payload data + extract channel information */ |
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}; |
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uint8_t frame_header = 0U; /* Frame header from SRXL datastream */ |
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uint8_t frame_len_full = 0U; /* Length in number of bytes of full srxl datastream */ |
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uint8_t decode_state = STATE_IDLE; /* Current state of SRXL frame decoding */ |
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uint8_t decode_state_next = STATE_IDLE; /* State of frame decoding thatwill be applied when the next byte from dataframe drops in */ |
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uint16_t crc_fmu = 0U; /* CRC calculated over payload from srxl datastream on this machine */ |
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uint16_t crc_receiver = 0U; /* CRC extracted from srxl datastream */ |
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SoftSerial ss{115200, SoftSerial::SERIAL_CONFIG_8N1}; |
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};
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