Establish a j-link GDB cross debugging environment for Px4

Version Description

1. Self driving instrument ：Holybro Of Pixhawk 4.

2. PX4 edition ：1.13

3. The host machine ：Thinkpad The notebook +Ubuntu 20.04.2 LTS

4. J-Link Software ：V760

5. J-Link Hardware ：J-Link EDU mini. You can buy it on Taobao ,170 yuan , The things you buy are shown in the figure below ：

One . Hardware interface

1.1 J-Link EDU mini Interface and Pixhawk 4 Debug Definition of mouth

Reference resources px4 Official website ：

SWD (JTAG) Hardware Debugging Interface | PX4 User Guide

1.1.1 J-Link EDU mini Of 10 Pin interface definition

1.1.2 J-Link EDU mini And SWD Connection diagram

SWD yes ARM A defined debugging interface ,Serial Wire Debug (SWD)

1.1.3 Pixhawk 4 Yes IO Debug Interface and FMU Debug Definition of interface

PIXHAWK 4 There are two Debug Port, One is IO Debug Port, The other is FMU Debug Port. Both ports provide Pixhawk standard 6-Pin SH Debug Port.（6 The needle ）

1.2 Pixhawk 4 Of IO Debug Port And J-Link EDU mini Mouth connection

Connection sequence description ：

Refer to the official website ：

SWD (JTAG) Hardware Debugging Interface | PX4 User Guide

Compare with the above 1,J-Link EDU mini10 Needle mouth definition and PIXHAWK 4 IO debug mouth 6 The connection of the needle is as follows ：

IO Debug Port	J-Link Mini
1 Vtref	1
2 TX	-
3 NC	-
4 SWDIO	2
5 SWDCLK	4
6 GND	3 perhaps 5

Cable description :

Pixhawk 4 Of debug port have 6 The pin socket is shown in the figure below ：

Need to adopt 6 The pin cable is connected to it ,Pixhawk 4 There is this wire in the wire package , You can do two , One used in IO debug mouth , The other is used in FMU Debug mouth . In addition, you can also buy from Dejie , website ： Dejie Electronics

A06SR06SR30K152A JST Sales America Inc. | Cable Assemblies | DigiKey

End to end pixhawk, The other end needs to be connected J-Link

J-Link Terminal 10 The pin sockets are as follows ：

The outgoing cable is connected by J-Link The manufacturer provides . Need to put J-Link EDU mini Outgoing 10 Pin The arrangement of wires shall be in accordance with the above line sequence Pixhawk 4 Provided 6 The pin cable is welded together （ Just connect 4 Root line ）, Due to the small spacing , So welding is a delicate job . The appearance after welding is shown in the figure , The solder joint is wrapped with green electrical tape .

Two . Software part

2.1 install SEGGER JLink Software

Open the following page

SEGGER - The Embedded Experts - Downloads - J-Link / J-Trace

stay Linux Select download... From the options 64-bit DEB Installer software package , The package will be downloaded to Downloads Directory ,

The downloaded file name is as follows JLink_Linux_V760h_x86_64.deb, Install this .deb software package ：

sudo dpkg -i ~/Downloads/JLink_Linux_V760h_x86_64.deb

After executing this order , The contents of the software package will be stored in /usr/bin Directory . This is a global installation , That is to say, it can be executed anywhere JLink The supplied is installed on /usr/bin Binary program in .

2.2 function JLink GDB Server

Carry out orders ：JLinkGDBServerExe, The graphical interface will pop up ：

In this interface, you need to fill in ,

Connection to J-Link：USB（Pixhawk It's through USB Connected to the host ）

Target device：STM32F765II（ This is you Pixhawk In board FMU The use of CPU model ）

Target interface：SWD（Pixhawk The connection mode with the host is SWD）

speed：Auto Selection

And then click OK Button .

Accept the requirements of the copyright statement , Don't forget , This is a very cheap debugging tool for Education .

The interface is GDB Server Interface , so ：

GDB： Waiting for connection（ explain GDB Server Is waiting for GDB Connection of the client ）

J-Link：Connected（ explain J-Link The hardware connection between the host and the target has been established ）

2.3 function GDB, debugging px4 Software

Open a new window , Enter into PX4-Autopilot Catalog , Run the following command :

arm-none-eabi-gdb build/px4_fmu-v5_default/px4_fmu-v5_default.elf
 stay gdb At the prompt , Carry out orders ：
gdb>target remote localhost:2331

 At this time can be in JLink GDB Server You can see it in the interface GDB Server And GDB The client has established a connection . stay gdb Client interface ,gdb take PX4 The program stops somewhere , Waiting for execution gdb command , You can execute continue Order to let PX4 Run up , use CTRL-C To interrupt the operation of a program ,PX4 The operating status of the can be found in JLink GDB Server Observation in the interface .