Scripting Debug Sessions: Python for GDB Remote Serial Protocol

Are you tired of hammering out the same commands over and over again in GDB? If not, we highly encourage you take more advantage of The GNU Project Debugger, which is a fantastic way to poke around inside your microcontrollers while they’re running a program.

Back to the matter at hand. [Stef] put together a Python program that leverages GDB’s Remote Serial Protocol. He calls it pyrsp and the talk he recently gave about it can be seen below.

The core feature is the ability to add a callback in your C code that triggers the Python script. Think of this a little bit like a print statement, except you have so much more power since it’s Python and GDB doing the “printing”. Anything that can be done at a breakpoint in GDB can now be executed automatically. So if you need to check a group of registers at every loop execution for hundreds of loops your wrists are going to thank you. Better yet, you can use Python to do the sanity checks automatically, continuing when the data is good and alerting you when it’s not. Neat!

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Proper Debugging for Energia Sketches

Moving a sketch from Energia to Code Composer Studio

Energia is a tool that brings the Arduino and Wiring framework to Texas Instruments’ MSP430 microcontrollers and the MSP430 Launchpad development board. This allows for easy development in an Arduino-like environment while targeting a different microcontroller family.

One problem with Energia and Arduino is the difficulty of debugging. Usually, we’re stuck putting a Serial.println(); and watching the serial port to trace what our program is doing. Other options include blinking LEDs, or using external displays.

Code Composer Studio, TI’s official development tool, allows for line-by-line debugging of applications. You can set breakpoints, watch the value of variables, and step through an application one instruction at a time.

The good news is that the latest version of Code Composer Studio supports importing Energia sketches. Once imported, you can step through the code and easily debug your application. This is a huge help to people developing more complex software using Energia, such as libraries.

TI gives us an overview of the new feature in a video after the break.

[Thanks to Adrian for the tip!]

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Profiling An Arduino

profiling

In proper, high-dollar embedded development environments – and quite a few free and open source ones, as well – you get really cool features like debugging, emulation, and profiling. The Arduino IDE doesn’t feature any of these bells a whistles, so figuring out how much time is spent in one section of code is nigh impossible. [William] came up with a clever solution to this problem, and while it doesn’t tell you exactly how much time is spent on a specific line of code, it’s still a good enough tool to be a great help in optimization.

[William]‘s solution is to create a ‘bin’ for arbitrary chunks of code – one for each subroutine or deeply nested loop. When the profiler run, you end up with a histogram of how much time is spent per block of code. This is done with an interrupt that runs at about 1 kHz, with macros sprinkled around the code. Each time the interrupt ticks, the macro runs and increases a counter by one. Let the sketch run for a minute or so, and you get an idea of how much time is spent in a specific area of code.

It’s a bit of a kludge, but when you’re dealing with extremely minimal tools, any sort of help in debugging is sorely needed and greatly appreciated.

 

 

Serial Monitor Without a PC

serial01

A serial monitor is an easy way to debug your projects. As we step through code, it’s nice to see a “Hey! I’m working, moving to next thing!” across the monitor, and not so nice to see nothing – the result of a bug that needs debugging. This has always meant needing a PC loaded with your favorite serial terminal program close at hand.

Most of the time this is not an issue, because the PC is used to compile the code and program the project at hand. But what if you’re in the field, with a mission of fixing a headless system, and in need a serial monitor? Why lug around your PC when you can make your own External Serial Monitor!

[ARPix] built this fully functional serial monitor based on an Atmega328 and a 102 x 64 LCD display. While it doesn’t have a keyboard port like this microcontroller based serial terminal, tact switches allow access to the user interface to start and stop the reading and set the baud rate. The Atmega328 has 2K of SRAM, which is needed for the project. Apparently, 1K was not enough to handle all the data. All code, schematics and a very well done parts layout are available, making this sure to be your next weekend project!

 

 

 

How to build OpenOCD with Stellaris Launchpad support

The stable version of OpenOCD (an open source On-Chip Debugging software package) doesn’t have support for the ICDI protocol used by the Stellaris Launchpad board. But it is pretty easy to build your own OpenOCD from source after patching it to use the protocol.

We’ve already seen an open source tool used to flash binary images to the TI ARM board. But that can’t be used with GDB. With the recent inclusion of USB-based ICDI in the OpenOCD development branches we gain all the features that come with the package. We’re quite happy hear about this as we use OpenOCD for many hardware architectures and this makes development for this board feel more like normal.

Our Stellaris Launchpad hasn’t just been sitting in the closet since we got it. We’ve learned a lot by using the lm4tools to program the chip as we work our way through the online workshop. We’re really beginning to like the Stellarisware peripheral library that has been provided. For us it works in a much more intuitive way than the one that STM uses with their ARM Discovery boards. We’d recommend taking a look at the workbook PDF (which is basically a verbose listing of what’s in the video series) and the library reference (called SW-DRL-UG-9453.pdf) which is in the docs folder of the Stellarisware package.

[via Dangerous Protoypes]

Debugging the Stellaris with OpenOCD

It looks as though Texas Instruments are really reaching out to the hacker community with their new ARM-powered Stellaris dev board. On the Stellarisiti forums, a member asked about the debugging options for the Stellaris board. The Stellaris already features an In-Circuit Debug Interface (ICDI), but unfortunately it’s a little hard to get working in Linux-ey environments.

One of the devs for the Open On-Chip Debugger was already talking with TI to get the ICDI spec released for the Stellaris board. TI released the info, and after quite a bit of work, everything is open for all to see.

Right now, OpenOCD support for the Stellaris is still incomplete, but there is an project up on the Gits that allows for multi-platform development for TI’s new board.

Needless to say, getting everything up and running is still a chore. That’s not really a concern, though; the Stellaris has only been around for a few months and it takes devs time to put all the required tools into nice, neat packages. We’re just glad TI is being so forthcoming with the relevant documentation, lest development becomes a million times harder.

Beginner’s look at On-Chip Debugging

As your embedded applications get more complicated an On-Chip Debugger will save you a lot of time when things don’t run quite right. On-Chip Debugging (OCD) is just what it sounds like — a way to run your program on the target chip that lets you pause execution to examine values and change them if need be. The Arduino has no built-in method of using OCD, but the AVR chips used by the boards do. The caveat is that you need a proper AVR programmer to access the Debug Wire protocol, or a JTAG interface for some of the larger chips. In this case I’m going to be using an STM32 Discovery Board to give you an overview of OCD. But this will work the same way for any chip that has hardware debugging capabilities. Many IDE’s have debugging support built right in so that you can use a nice GUI as you work. But often these are just a front end for the command line tools I’ll be using. Join me after the break and we’ll get started.

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