Where I show a simple method of using gdb to debug code on the RP2040 (Pi Pico board).

Sources#

• Raspberry Pi Pico SDK: Raspberry Pi Pico SDK
• Raspberry Pi Pico Pinout
• GDB Documentation
• Guide to Faster, Less Frustrating Debugging - Norman Matloff
• gdb Resources

Setup .gdbinit#

The Guide recommends at the very least, add “target remote localhost:3333” to your .gdbinit file. To make our edit/compile/link/load round trip easy, I recommend the following for your .gdbinit:

All of the resources found related to gdb (particularly, related to the RP2040) and how to use it.

GNU gdb documentation#

• GDB: The GNU Project Debugger
• Online User Manual: Debugging with GDB
• PDF User Manual: Debugging with GDB

gdb Tutorials#

• Guide to Faster, Less Frustrating Debugging
• CSE 351: GDB (Gnu DeBugger)
• Quick Guide to gdb: The GNU Debugger
• Beej’s Quick Guide to GDB
• gdb Debugger Tutorial
• gdb Tutorial Site
• Hackaday: LOCAL AND REMOTE DEBUGGING WITH GDB
• Hackaday: BEGINNER’S LOOK AT ON-CHIP DEBUGGING
• 8 gdb tricks you should know
• Debugging Firmware with GDB
• GDB — Basics
• 10 Things You Can Only Do With gdb
• GDB Tutorial: Some Cool Tips to Debug C/C++ Code
• Advanced GDB Usage

Cheat Sheets#

• YoLinux: GNU GDB Debugger Command Cheat Sheet

Tools to enhance gdb#

• gdb-dashboard
• pyrsp: simple wrapper around the GDB Remote serial protocol
• gdbundle - GDB and LLDB’s Missing Plugin
• Visual debugging using gdbgui

AVR gdb#

• AVR-GDB Tutorial
• avr-gdb Notes
• man avarice

AVR gdb Notes#

1. Check the version number on avr-gdb as of December 2021, it is 11.1. On Ubuntu, the latest version is 8.1 from 2018 which had quite a few bugs. Attempted to build it manually (which failed), so I spun up a Manjaro (Arch Linux) instance to get the latest. Crazy, I know.
2. Start avarice in a separate window using, then launch gdb in another window:

   avarice -g -w -d -P atmega328p :3333 	# window 1
   avr-gdb -tui							# window 2

3. If avarice crashes on startup, cycle power on both the debugger (Dragon) and the target (Uno)

Pico (RP2040) gdb#

• Debugging the BBC micro:bit with pyOCD and GDB
• Raspberry Pico: Simple Debugging with just one Device
• Pico-debug
• PicoReg: real-time diagnostics for the Pi Pico using SWD