mirror of
https://github.com/ArduPilot/ardupilot
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AP_HAL: added support for more SRXL varients
based on work by Roman Seb <roman-29188@gmx.de>
This commit is contained in:
Andrew Tridgell
parent
65ce9821be
commit
5934a099a4
@ -15,81 +15,170 @@
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/*
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SRXL protocol decoder, tested against AR7700 SRXL port
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Andrew Tridgell, September 2016
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Co author: Roman Kirchner, September 2016
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- 2016.10.23: SRXL variant V1 sucessfully (Testbench and Pixhawk/MissionPlanner) tested with RX-9-DR M-LINK (SW v1.26)
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*/
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#include <stdio.h>
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#include <stdint.h>
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#include <stdbool.h>
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#include <string.h>
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#include "srxl.h"
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/*
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there are other SRXL varients, but we need some sample data before accepting them
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*/
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#define SRXL_MAX_CHANNELS 20
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#define SRXL_HEAD_MARKER 0xA5
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#define SRXL_NUM_BYTES 18
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static uint8_t buffer[SRXL_NUM_BYTES];
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static uint8_t buflen;
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static uint64_t last_data_us;
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static uint16_t channels[SRXL_MAX_CHANNELS];
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/* SRXL datastream characteristics for all variants */
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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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/* decode progress states */
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#define STATE_IDLE 0x00U /* do nothing */
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#define STATE_NEW 0x01U /* get header of frame + prepare for frame reception + begin new crc cycle */
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#define STATE_COLLECT 0x02U /* collect RC channel data from frame + concurrently calc crc over payload data + extract channel information */
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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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static 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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static uint8_t buflen; /* length in number of bytes of received srxl dataframe in buffer */
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static uint64_t last_data_us; /* timespan since last received data in us */
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static uint16_t channels[SRXL_MAX_CHANNELS]; /* buffer for extracted RC channel data as pulsewidth in microseconds */
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static uint8_t frame_header = 0U; /* Frame header from SRXL datastream */
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static uint8_t frame_len_full = 0U; /* Length in number of bytes of full srxl datastream */
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static uint8_t decode_state = STATE_IDLE; /* Current state of SRXL frame decoding */
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static 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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static uint16_t crc_fmu = 0U; /* CRC calculated over payload from srxl datastream on this machine */
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static uint16_t crc_receiver = 0U; /* CRC extracted from srxl datastream */
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static uint16_t max_channels;
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/*
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get SRXL crc16 for a set of bytes
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*/
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static uint16_t srxl_crc16(const uint8_t *bytes, uint8_t nbytes)
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{
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uint16_t crc = 0;
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while (nbytes--) {
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int i;
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crc ^= (uint16_t)(*bytes++) << 8;
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for (i = 0; i < 8; i++) {
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/**
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* This function calculates the 16bit crc as used throughout the srxl protocol variants
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*
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* This function is intended to be called whenever a new byte shall be added to the crc.
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* Simply provide the old crc and the new data byte and the function return the new crc value.
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*
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* To start a new crc calculation for a new srxl frame, provide parameter crc=0 and the first byte of the frame.
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*
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* @param[in] crc - start value for crc
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* @param[in] new_byte - byte that shall be included in crc calculation
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* @return calculated crc
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*/
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static uint16_t srxl_crc16 (uint16_t crc, uint8_t new_byte)
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{
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uint8_t loop;
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crc = crc ^ (uint16_t)new_byte << 8;
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for(loop = 0; loop < 8; loop++) {
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crc = (crc & 0x8000) ? (crc << 1) ^ 0x1021 : (crc << 1);
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}
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}
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return crc;
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}
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/*
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decode a SRXL packet
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/**
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* Get RC channel information as microsecond pulsewidth representation from srxl version 1 and 2
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*
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* This function extracts RC channel information from srxl dataframe. The function expects the whole dataframe
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* in correct order in static array "buffer[SRXL_FRAMELEN_MAX]". After extracting all RC channel information, the data
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* is transferred to "values" array from parameter list. If the pixhawk does not support all channels from srxl datastream,
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* only supported number of channels will be refreshed.
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*
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* IMPORTANT SAFETY NOTICE: This function shall only be used after CRC has been successful.
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*
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* Structure of SRXL v1 dataframe --> 12 channels, 12 Bit per channel
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* Byte0: Header 0xA1
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* Byte1: Bits7-4:Empty Bits3-0:Channel1 MSB
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* Byte2: Bits7-0: Channel1 LSB
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* (....)
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* Byte23: Bits7-4:Empty Bits3-0:Channel12 MSB
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* Byte24: Bits7-0: Channel12 LSB
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* Byte25: CRC16 MSB
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* Byte26: CRC16 LSB
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*
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* Structure of SRXL v2 dataframe --> 16 channels, 12 Bit per channel
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* Byte0: Header 0xA2
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* Byte1: Bits7-4:Empty Bits3-0:Channel1 MSB
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* Byte2: Bits7-0: Channel1 LSB
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* (....)
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* Byte31: Bits7-4:Empty Bits3-0:Channel16 MSB
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* Byte32: Bits7-0: Channel16 LSB
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* Byte33: CRC16 MSB
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* Byte34: CRC16 LSB
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*
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* @param[in] max_values - maximum number of values supported by the pixhawk
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* @param[out] num_values - number of RC channels extracted from srxl frame
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* @param[out] values - array of RC channels with refreshed information as pulsewidth in microseconds Range: 800us - 2200us
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* @param[out] failsafe_state - true: RC-receiver is in failsafe state, false: RC-receiver is not in failsafe state
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* @return 0: success
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*/
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int srxl_decode(uint64_t timestamp_us, uint8_t byte, uint8_t *num_values, uint16_t *values, uint16_t max_values, bool *failsafe_state)
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static int srxl_channels_get_v1v2(uint16_t max_values, uint8_t *num_values, uint16_t *values, bool *failsafe_state)
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{
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if (timestamp_us - last_data_us > 5000U || buflen == SRXL_NUM_BYTES) {
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// we've seen a frame gap
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if (buflen != 0) {
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buflen = 0;
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}
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}
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last_data_us = timestamp_us;
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buffer[buflen++] = byte;
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uint8_t loop;
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uint32_t channel_raw_value;
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switch (buffer[0]) {
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case SRXL_HEAD_MARKER:
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break;
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*num_values = (uint8_t)((frame_len_full - 3U)/2U);
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*failsafe_state = 0U; /* this protocol version does not support failsafe information */
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default:
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// invalid packet, we don't support this format yet
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return 2;
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/* get data channel data from frame */
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for (loop=0U; loop < *num_values; loop++) {
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channel_raw_value = ((((uint32_t)buffer[loop*2U+1U])& 0x0000000FU) << 8U) | ((uint32_t)(buffer[loop*2U+2U])); /* get 12bit channel raw value from srxl datastream (mask out unused bits with 0x0000000F) */
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channels[loop] = (uint16_t)(((channel_raw_value * (uint32_t)1400U) >> 12U) + (uint32_t)800U); /* convert raw value to servo/esc signal pulsewidth in us */
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}
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uint8_t expected_bytes = SRXL_NUM_BYTES;
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if (buflen < expected_bytes) {
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// more bytes pending
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return 1;
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/* provide channel data to FMU */
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if ( (uint16_t)*num_values > max_values) {
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*num_values = (uint8_t)max_values;
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}
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memcpy(values, channels, (*num_values)*2);
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return 0; /* for srxl protocol version 1 and 2 it is not expected, that any error happen during decode process */
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}
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uint16_t crc = srxl_crc16(buffer, buflen-2);
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uint64_t crc2 = buffer[buflen-1] | (buffer[buflen-2]<<8);
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if (crc != crc2) {
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// bad CRC
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return 4;
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}
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/**
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* Get RC channel information as microsecond pulsewidth representation from srxl version 5
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*
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* This function extracts RC channel information from srxl dataframe. The function expects the whole dataframe
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* in correct order in static array "buffer[SRXL_FRAMELEN_MAX]". After extracting all RC channel information, the data
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* is transferred to "values" array from parameter list. If the pixhawk does not support all channels from srxl datastream,
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* only supported number of channels will be refreshed.
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*
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* IMPORTANT SAFETY NOTICE: This function shall only be used after CRC has been successful.
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*
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* Structure of SRXL v5 dataframe
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* Byte0: Header 0xA5
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* Byte1 - Byte16: Payload
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* Byte17: CRC16 MSB
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* Byte18: CRC16 LSB
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*
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* @param[in] max_values - maximum number of values supported by the pixhawk
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* @param[out] num_values - number of RC channels extracted from srxl frame
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* @param[out] values - array of RC channels with refreshed information as pulsewidth in microseconds Range: 800us - 2200us
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* @param[out] failsafe_state - true: RC-receiver is in failsafe state, false: RC-receiver is not in failsafe state
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* @return 0: success
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*/
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static int srxl_channels_get_v5(uint16_t max_values, uint8_t *num_values, uint16_t *values, bool *failsafe_state)
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{
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// up to 7 channel values per packet. Each channel value is 16
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// bits, with 11 bits of data and 4 bits of channel number. The
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// top bit indicates a special X-Plus channel
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@ -98,12 +187,10 @@ int srxl_decode(uint64_t timestamp_us, uint8_t byte, uint8_t *num_values, uint16
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uint16_t c = b >> 11; // channel number
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int32_t v = b & 0x7FF;
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if (b & 0x8000) {
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//printf("bad data 0x%04x\n", b);
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// bad data
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return 2;
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continue;
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}
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if (c == 12) {
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// special handling for channel 12, this contains the XPlus channels
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// special handling for channel 12
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// see http://www.deviationtx.com/forum/protocol-development/2088-18-channels-for-dsm2-dsmx?start=40
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//printf("c12: 0x%x %02x %02x\n", (unsigned)(b>>9), (unsigned)buffer[0], (unsigned)buffer[1]);
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v = (b & 0x1FF) << 2;
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@ -120,6 +207,10 @@ int srxl_decode(uint64_t timestamp_us, uint8_t byte, uint8_t *num_values, uint16
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v = 0;
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}
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// if channel number if greater than 16 then it is a X-Plus
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// channel. We don't yet know how to decode those. There is some information here:
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// http://www.deviationtx.com/forum/protocol-development/2088-18-channels-for-dsm2-dsmx?start=40
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// but we really need some sample data to confirm
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if (c < SRXL_MAX_CHANNELS) {
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v = (((v - 0x400) * 500) / 876) + 1500;
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channels[c] = v;
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@ -142,17 +233,119 @@ int srxl_decode(uint64_t timestamp_us, uint8_t byte, uint8_t *num_values, uint16
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// transmitter is lost
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*failsafe_state = ((buffer[1] & 2) == 0);
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#if 0
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for (uint8_t i=0; i<buflen; i++) {
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printf("%02x ", (unsigned)buffer[i]);
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}
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printf("\n");
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#endif
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buflen = 0;
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// success
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return 0;
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}
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/**
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* Decode SRXL frames
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*
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*
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* Structure of all SRXL frames
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* Byte[0]: Header 0xA<VARIANT> --> Variant specific header. Variant is encoded in bits 3-0 of header byte.
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* Byte[1] - Byte[N-2]: SRXL variant specific payload
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* Byte[N-1] - Byte[N]: CRC16 over payload and header
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*
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* @param[in] timestamp_us - timestamp in microseconds
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* @param[in] received byte in microseconds
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* @param[out] num_values - number of RC channels extracted from srxl frame
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* @param[out] values - array of RC channels with refreshed information as pulsewidth in microseconds Range: 800us - 2200us
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* @param[in] maximum number of values supported by pixhawk
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* @param[out] failsafe_state - true: RC-receiver is in failsafe state, false: RC-receiver is not in failsafe state
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* @return 0: success
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*/
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int srxl_decode(uint64_t timestamp_us, uint8_t byte, uint8_t *num_values, uint16_t *values, uint16_t max_values, bool *failsafe_state)
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{
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int ret = 1;
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/*----------------------------------------distinguish different srxl variants at the beginning of each frame---------------------------------------------- */
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/* Check if we have a new begin of a frame --> indicators: Time gap in datastream + SRXL header 0xA<VARIANT>*/
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if ( (timestamp_us - last_data_us) >= SRXL_MIN_FRAMESPACE_US) {
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/* Now detect SRXL variant based on header */
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switch(byte) {
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case SRXL_HEADER_V1:
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frame_len_full = SRXL_FRAMELEN_V1;
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frame_header = SRXL_HEADER_V1;
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decode_state = STATE_NEW;
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break;
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case SRXL_HEADER_V2:
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frame_len_full = SRXL_FRAMELEN_V2;
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frame_header = SRXL_HEADER_V2;
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decode_state = STATE_NEW;
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break;
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case SRXL_HEADER_V5:
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frame_len_full = SRXL_FRAMELEN_V5;
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frame_header = SRXL_HEADER_V5;
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decode_state = STATE_NEW;
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break;
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default:
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frame_len_full = 0U;
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frame_header = SRXL_HEADER_NOT_IMPL;
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decode_state = STATE_IDLE;
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ret = 2; /* protocol version not implemented --> no channel data --> unknown packet */
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break;
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}
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}
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/*--------------------------------------------collect all data from stream and decode-------------------------------------------------------*/
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switch (decode_state) {
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case STATE_NEW: /* buffer header byte and prepare for frame reception and decoding */
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buffer[0U]=byte;
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crc_fmu = srxl_crc16(0U,byte);
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buflen = 1U;
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decode_state_next = STATE_COLLECT;
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break;
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case STATE_COLLECT: /* receive all bytes. After reception decode frame and provide rc channel information to FMU */
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buffer[buflen] = byte;
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buflen++;
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/* CRC not over last 2 frame bytes as these bytes inhabitate the crc */
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if (buflen <= (frame_len_full-2)) {
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crc_fmu = srxl_crc16(crc_fmu,byte);
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}
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if( buflen == frame_len_full ) {
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/* CRC check here */
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crc_receiver = ((uint16_t)buffer[buflen-2] << 8U) | ((uint16_t)buffer[buflen-1]);
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if (crc_receiver == crc_fmu) {
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/* at this point buffer contains all frame data and crc is valid --> extract channel info according to SRXL variant */
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switch (frame_header) {
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case SRXL_HEADER_V1:
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ret = srxl_channels_get_v1v2(max_values, num_values, values, failsafe_state);
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break;
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case SRXL_HEADER_V2:
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ret = srxl_channels_get_v1v2(max_values, num_values, values, failsafe_state);
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break;
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case SRXL_HEADER_V5:
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ret = srxl_channels_get_v5(max_values, num_values, values, failsafe_state);
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break;
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default:
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ret = 2; /* protocol version not implemented --> no channel data */
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break;
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}
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}
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else {
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ret = 4; /* CRC fail --> no channel data */
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}
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decode_state_next = STATE_IDLE; /* frame data buffering and decoding finished --> statemachine not in use until new header drops is */
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}
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else {
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/* frame not completely received --> frame data buffering still ongoing */
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decode_state_next = STATE_COLLECT;
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}
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break;
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default:
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ret = 1; /* STATE_IDLE --> do nothing */
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break;
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} /* switch (decode_state) */
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decode_state = decode_state_next;
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last_data_us = timestamp_us;
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return ret;
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}
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@ -218,7 +411,7 @@ int main(int argc, const char *argv[])
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tv.tv_usec = 0;
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// check if any bytes are available
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if (select(fd+1, &fds, nullptr, nullptr, &tv) != 1) {
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if (select(fd+1, &fds, NULL, NULL, &tv) != 1) {
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break;
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}
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@ -240,7 +433,7 @@ int main(int argc, const char *argv[])
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#endif
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#ifdef TEST_HEX_PROGRAM
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#ifdef TEST_BIN_PROGRAM
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/*
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test harness for use under Linux with hex dump in a file
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*/
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@ -267,25 +460,43 @@ int main(int argc, const char *argv[])
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uint16_t values[20];
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bool failsafe_state;
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unsigned u[18];
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if (fscanf(f, "%02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
|
||||
&u[0], &u[1], &u[2], &u[3], &u[4], &u[5], &u[6], &u[7], &u[8], &u[9],
|
||||
&u[10], &u[11], &u[12], &u[13], &u[14], &u[15], &u[16], &u[17]) != 18) {
|
||||
|
||||
uint8_t header;
|
||||
if (fread(&header, 1, 1, f) != 1) {
|
||||
break;
|
||||
}
|
||||
|
||||
uint8_t frame_size = 0;
|
||||
switch (header) {
|
||||
case SRXL_HEADER_V1:
|
||||
frame_size = SRXL_FRAMELEN_V1;
|
||||
break;
|
||||
case SRXL_HEADER_V2:
|
||||
frame_size = SRXL_FRAMELEN_V2;
|
||||
break;
|
||||
case SRXL_HEADER_V5:
|
||||
frame_size = SRXL_FRAMELEN_V5;
|
||||
break;
|
||||
}
|
||||
if (frame_size == 0) {
|
||||
continue;
|
||||
}
|
||||
uint8_t u[frame_size];
|
||||
u[0] = header;
|
||||
if (fread(&u[1], 1, sizeof(u)-1, f) != sizeof(u)-1) {
|
||||
break;
|
||||
}
|
||||
t += 11000;
|
||||
|
||||
for (uint8_t i=0; i<18; i++) {
|
||||
for (uint8_t i=0; i<sizeof(u); i++) {
|
||||
b = u[i];
|
||||
|
||||
if (srxl_decode(t, b, &num_values, values, sizeof(values)/sizeof(values[0]), &failsafe_state) == 0) {
|
||||
#if 1
|
||||
printf("%u: ", num_values);
|
||||
for (uint8_t i=0; i<num_values; i++) {
|
||||
printf("%u:%4u ", i+1, values[i]);
|
||||
}
|
||||
printf("%s\n", failsafe_state?"FAIL":"OK");
|
||||
#endif
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user