This repository has been archived by the owner on Oct 1, 2021. It is now read-only.
forked from PX4/PX4-Autopilot
-
Notifications
You must be signed in to change notification settings - Fork 441
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
PX4IO: Added support for JR XBus Mode B
JR XBus Mode B uses the same serial port parameters as the DSM port (3.3V logic, 115200, 8n1), this update adds support for decoding it. XBus Mode B is effectively the SRXL protocol, using the Multiplex 12-channel format (start charachter 0xA1) Decoding of XBus packets only occurs if a valid checksum is received, so this should not interfere with DSM packets. - RC Failsafe is now disabled when XBus data is bein received
- Loading branch information
Owen McAree
committed
May 20, 2015
1 parent
548f37a
commit 4fb3e8c
Showing
5 changed files
with
194 additions
and
20 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,152 @@ | ||
| /**************************************************************************** | ||
| * | ||
| * Copyright (c) 2012-2014 PX4 Development Team. All rights reserved. | ||
| * | ||
| * Redistribution and use in source and binary forms, with or without | ||
| * modification, are permitted provided that the following conditions | ||
| * are met: | ||
| * | ||
| * 1. Redistributions of source code must retain the above copyright | ||
| * notice, this list of conditions and the following disclaimer. | ||
| * 2. Redistributions in binary form must reproduce the above copyright | ||
| * notice, this list of conditions and the following disclaimer in | ||
| * the documentation and/or other materials provided with the | ||
| * distribution. | ||
| * 3. Neither the name PX4 nor the names of its contributors may be | ||
| * used to endorse or promote products derived from this software | ||
| * without specific prior written permission. | ||
| * | ||
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | ||
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | ||
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS | ||
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE | ||
| * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, | ||
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, | ||
| * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS | ||
| * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED | ||
| * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | ||
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN | ||
| * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | ||
| * POSSIBILITY OF SUCH DAMAGE. | ||
| * | ||
| ****************************************************************************/ | ||
|
|
||
| /** | ||
| * @file dsm.c | ||
| * | ||
| * Serial protocol decoder for the JR XBus protocol. | ||
| * | ||
| * Uses XBus Mode B which is the Multiplex SRXL protocol, details here | ||
| * http://www.multiplex-rc.de/en/service/downloads/interface-descriptions.html?eID=dam_frontend_push&docID=4233 | ||
| * | ||
| * Decodes into the global PPM buffer and updates accordingly. | ||
| */ | ||
|
|
||
| #include <nuttx/config.h> | ||
| #include <nuttx/arch.h> | ||
|
|
||
| #include <fcntl.h> | ||
| #include <unistd.h> | ||
| #include <termios.h> | ||
| #include <string.h> | ||
|
|
||
| #include <drivers/drv_hrt.h> | ||
|
|
||
| #include "px4io.h" | ||
|
|
||
| #define XBUS_NUM_CHANNELS 12 /**<Number of XBus channels*/ | ||
| #define XBUS_PACKET_LENGTH 3 + XBUS_NUM_CHANNELS*2 | ||
|
|
||
| static int bytesReceived = 0; /**<Number of bytes received since start character */ | ||
| static uint8_t xbus_buffer[XBUS_PACKET_LENGTH]; | ||
|
|
||
| uint16_t CRC16(uint16_t crc, uint8_t value); | ||
|
|
||
| uint16_t CRC16(uint16_t crc, uint8_t value) | ||
| { | ||
| uint8_t i; | ||
| crc = crc ^ (int16_t)value<<8; | ||
| for(i = 0; i < 8; i++) { | ||
| if(crc & 0x8000) | ||
| crc = crc << 1^0x1021; | ||
| else | ||
| crc = crc << 1; | ||
| } | ||
| return crc; | ||
| } | ||
|
|
||
| /** | ||
| * Called periodically to check for input data from the XBus UART | ||
| * | ||
| * | ||
| * | ||
| * @param[in] bytes received through DSM serial port | ||
| * @param[in] number of bytes received through DSM serial port | ||
| * @param[out] values pointer to per channel array of decoded values | ||
| * @param[out] num_values pointer to number of raw channel values returned | ||
| * @return true=decoded raw channel values updated, false=no update | ||
| */ | ||
| bool | ||
| xbus_input(uint8_t *bytes, uint16_t num_bytes, uint16_t *values, uint16_t *num_values) | ||
| { | ||
| /* If we have no new data, return here */ | ||
| if (num_bytes < 1) | ||
| return false; | ||
|
|
||
| /* Copy new bytes in to our buffer */ | ||
| memcpy(xbus_buffer + bytesReceived, bytes, num_bytes); | ||
|
|
||
| /* If start character is not correct, reset everything */ | ||
| if (xbus_buffer[0] != 0xA1) { | ||
| memset(xbus_buffer, '\0', XBUS_PACKET_LENGTH); | ||
| bytesReceived = 0; | ||
| return false; | ||
| } | ||
|
|
||
| /* Increment buffer length */ | ||
| bytesReceived += num_bytes; | ||
|
|
||
| /* If we don't have a full packet, return here */ | ||
| if (bytesReceived < XBUS_PACKET_LENGTH) | ||
| return false; | ||
|
|
||
| /* Reset counter ready for next packet */ | ||
| bytesReceived = 0; | ||
|
|
||
| /* Check CRC of packet */ | ||
| uint16_t crc_calc = 0; | ||
| for (int i=0; i< XBUS_PACKET_LENGTH-2; i++) { | ||
| crc_calc = CRC16(crc_calc, xbus_buffer[i]); | ||
| } | ||
| uint16_t crc_buffer = ((uint16_t)(xbus_buffer[XBUS_PACKET_LENGTH - 2]))<<8 | (uint16_t)(xbus_buffer[XBUS_PACKET_LENGTH - 1]); | ||
| if (crc_calc != crc_buffer) | ||
| return false; | ||
|
|
||
|
|
||
| /* Apply this channel mapping to get correct order | ||
| * JR XBus Mode B order is: | ||
| * - Aileron | ||
| * - Elevator | ||
| * - Rudder | ||
| * - Aux 2 (Flap) | ||
| * - Throttle | ||
| * - Aux 1 (Gear) | ||
| * - Aux 3 | ||
| * - Aux 4 | ||
| * - etc... | ||
| **/ | ||
| uint8_t chMap[] = {1, 2, 3, 5, 0, 4, 6, 7, 8, 9, 10, 11}; | ||
| *num_values = XBUS_NUM_CHANNELS; | ||
|
|
||
| /* Channel scaling is linear between | ||
| * - 0x000: 800us | ||
| * - 0xfff: 2200us | ||
| **/ | ||
| for (int channel = 0; channel<XBUS_NUM_CHANNELS; channel++) { | ||
| uint32_t value = (((uint16_t)xbus_buffer[2*channel+1])<<8) | ((uint16_t)xbus_buffer[2*channel+2]); | ||
| double dblVal = value*(2200.0-800.0)/4095.0 + 800.0; | ||
| values[chMap[channel]] = (uint16_t)dblVal; | ||
| } | ||
| return true; | ||
| } |