# Pixhawk系列的配套计算机

Pixhawk与配套计算机(Raspberry Pi,Odroid,Tegra K1) 的交互方式只有一种:通过串口2 TELEM 2。 消息格式是MAVLINK。

# Pixhawk设置

在 任何 可配置的串口 (opens new window)上使能MAVLink消息。

提示

Typically the TELEM 2 port is used for a companion computer.

更多信息,请参考 MAVLink Peripherals (GCS/OSD/Companion) (opens new window)

  • MAV_1_CONFIG = TELEM 2 (MAV_1_CONFIG总是配置为 TELEM 2 端口)
  • MAV_1_MODE = Onboard
  • SER_TEL2_BAUD = 921600(建议在像日志流或FastRTPS之类的应用,使用 921600 或更高)

更多信息,请参考 MAVLink Peripherals (GCS/OSD/Companion)

# 配套计算机设置

按照以下说明连接串行端口。 所有 pixhawk 串行端口都以 3.3 v 电平工作,同时与5v 电平兼容。

# 硬件设置

安全的选择是使用 ftdi 芯片 usb 到串行适配器板和下面的接线方式。 这种方式有效且容易设置。

在 linux 上, usb ftdi 的默认名称将类似于 \dev\ttyUSB0。 如果您在 usb 或 arduino 上连接了第二个 ftdi, 它将注册为 \dev\ttyUSB1。 为了避免第一次插入和第二个插头之间的混淆, 我们建议您创建一个从 ttyUSBx 到友好名称的符号链接, 具体取决于 usb 设备的供应商和产品 ID。 :::

The safe bet is to use an FTDI Chip USB-to-serial adapter board and the wiring below. This always works and is easy to set up.

TELEM2 FTDI
1 1 DO NOT CONNECT!
2 2 Tx (输出) 5
3 3 Rx(输入) 4
4 4 CTS(输入) 6
5 5 RTS(输出) 2
6 6 GND 1

# Linux系统上的软件设置

On Linux the default name of a USB FTDI would be like \dev\ttyUSB0. If you have a second FTDI linked on the USB or an Arduino, it will registered as \dev\ttyUSB1. To avoid the confusion between the first plugged and the second plugged, we recommend you to create a symlink from ttyUSBx to a friendly name, depending on the Vendor and Product ID of the USB device.

Pixhawk 是 Bus 003 Device 005: ID 26ac:0011

$lsusb
    总线006 设备002:ID 0BDA:8153 Realtek 半导体公司
    Bus 006 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
    Bus 005 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
    Bus 004 Device 002: ID 05e3:0616 Genesys Logic, Inc.
    Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
    Bus 003 Device 004: ID 2341:0042 Arduino SA Mega 2560 R3 (CDC ACM)
    Bus 003 Device 005: ID 26ac:0011
    Bus 003 Device 002: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
    Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
    Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
    Bus 001 Device 002: ID 0bda:8176 Realtek Semiconductor Corp. RTL8188CUS 802.11n WLAN Adapter
    Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

最终,我们可以在文件中创建一个新的UDEV规则,文件名是/etc/udev/rules.d/99-pixhawk.rules 。 文件能把idVendor和idProduct改成你的。

最后, 在 reboot 后, 您可以确定您的设备名, 并将 /dev/ttyPixhawk替换掉在脚本中的 /dev/ttyUSB0

注解

If you do not find your device, unplug it, execute lsusb, plug it, execute lsusb again and see the added device.

Therefore, we can create a new UDEV rule in a file called /etc/udev/rules.d/99-pixhawk.rules with the following content, changing the idVendor and idProduct to yours.

SUBSYSTEM=="tty", ATTRS{idVendor}=="2341", ATTRS{idProduct}=="0042", SYMLINK+="ttyArduino"
    SUBSYSTEM=="tty", ATTRS{idVendor}=="26ac", ATTRS{idProduct}=="0011", SYMLINK+="ttyPixhawk"

Finally, after a reboot you can be sure to know which device is what and put /dev/ttyPixhawk instead of /dev/ttyUSB0 in your scripts.

注解

Be sure to add yourself in the tty and dialout groups via usermod to avoid to have to execute scripts as root.

usermod -a -G tty ros-user
    usermod -a -G dialout ros-user