Nios® V Processor Software Developer Handbook

ID 743810
Date 10/06/2025
Public
Document Table of Contents

18.2.3.4. OpenOCD

Nios® V processor supports the Open On-Chip Debugger for debugging. Open On-Chip Debugger(OpenOCD), is an open source GNU Project Debugger(GDB) server implementation that allows a GDB Client to debug embedded target device. In a standard setup, OpenOCD translates debugging Remote Serial Protocol instructions from the GDB client into signals that is understood by the target device, then requests the device to perform the required action and communicate the result back to the GDB client.

Utility path:../<QPDS version>/quartus/bin64/openocd.exe

Synopsis

openocd [OPTIONS] <CONFIGURATION FILE>

Description

To start a OpenOCD client session using desired device configuration file .

Once you have connected to the OpenOCD client (through gdb, tcl or telnet), run the OpenOCD commands to start debugging. For more information about the list of OpenOCD commands, refer to OpenOCD: General Commands or RISC-V Architecture and Core Commands.

Usage

Launching OpenOCD
# Ensure Nios V processor is detected in the JTAG scan chain
$ jtagconfig -n

1) Agilex 5E065B Premium DK [USB-1]
  0364F0DD   A5E(C065BB32AR0|D065BB32AR0)
    Design hash    0E5A4B074FCDE48D4128
    + Node 08986E00  Nios V #0
    + Node 0C006E00  JTAG UART #0
    + Node 0C206E00  JTAG PHY #0
  020D10DD   VTAP10

# Create OpenOCD configuration file
$ openocd-cfg-gen niosv.cfg

# Launch and Verify OpenOCD
$ openocd -f niosv.cfg

Open On-Chip Debugger 0.11.0-R22.4
Licensed under GNU GPL v2
...[omitted for brevity]...
Info : Listening on port 3333 for gdb connections
Info : Listening on port 6666 for tcl connections
Info : Listening on port 4444 for telnet connections

Connecting to gdb debugger on another terminal (command prompt)
Connecting to gdb debugger on another terminal (command prompt)
# Launch and Verify GDB debugger
$ riscv32-unknown-elf-gdb app_hal.elf -ex 'target extended-remote localhost:3333'

GNU gdb (GDB) 13.2
Copyright (C) 2023 Free Software Foundation, Inc.
...[omitted for brevity]...
Remote debugging using localhost:3333
0x00000004 in ?? ()
(gdb)
Connecting to telnet on another terminal (command prompt)
# Launch and Verify Telnet connection
$ telnet 127.0.0.1 4444

Open On-Chip Debugger
>

Options

Options Description
-h, --help Display help menu
-f, --file Use configuration file <name>
-c, --command Run <command>
-d or -d<n>, --debug or --debug<n> Set debug level to <level>, default value = 3 without <n> argument
-v, --version Display OpenOCD version
-s, --search Search for config files and scripts
l, --log_output- Redirect log output to file <name>