Debugging your arduino

While I'm waiting for my first OLED screen to arrive, I decided to learn more about the debugging options available for the Arduino.

I found 4 alternatives:

• Hardware
• Emulators
• Print
• Drivers

In the end the option most attractive to me at this point is to add debugging drivers to my code.
But I'll list the other options first...

Hardware:

There are a few variants out there, costing ctom $10-$100+:
Atmega328P Xplained Mini, AVR Dragon, JTAGICE2, AVR One, JTAGICE3

The cheapest one is the Atmega328P Xplained Mini at ~$10. Unfortunately, it seems very tied to the Atmel Studio which is only supported on Windows.

Emulators:

I found 2 emulators, each with similar feature sets, but one seems a bit legacy at this point:

• Simulavr - git (legacy) - howto
• Simavr - git

Both emulators have the option to sample the output pins, and log the values into a .vcd file, which can be displayed with gtkwave.

Print:

It's of course important to mention that you can do print debugging too when you need it

Drivers:

After stumbling across this post by Jan Dolinay, I wanted to see it it worked for my cheap arduino.
I turned out it was farily easy to build it. There was a few caveats (mentioned by Jan in his post) regarding the serial interface, but in essence, you cannot use the Serial class since the debugger uses the serial port. But there is a debug_message(const char* msg) that can be used instead.

Build notes:

• Add the avr8-stub.c to your build, add avr8-stub.h to your main.cpp
• Overwrite the WInterrupts.c in your core library
• Call debug_init() in your setup() function
• [Optional] Set programmatic breakpoints using breakpoint()
• Add flags "-Og" and "-gdwarf-2"

Debugging:

Once you've built the .hex file and uploaded it, it's time to run avr-gdb:

• Upload the myprog.hex file with avrdude
• Run debugger with, connecting to your serial port:
• avr-gdb -ex "target remote /dev/cu.wchusbserial1410" -b 115200 myprog.elf

And, that's it! Now you can debug using breakpoints as usual.

Happy Debugging!

Sublime Text 3 custom build

Adding a custom build step to Sublime Text 3 is easy.

Simply choose

"Tools -> Build System -> New Build System"

and it will create a new .sublime-build file that you can configure to your liking.

How to configure it, can be found in the Configuration manual.

In my case, I wanted to invoke the build.sh file in the project root directory:

// The initial version

{
    "cmd": ["sh", "build.sh"],
    "working_dir": "${project_path:${folder}}"
}

Build output

The final output

Next, I needed to capture the output from the compiler, and in this case, it's from the arduino compilers. Unfortunately, the ansi output they produce couldn't be handled by either Sublime Text 3 or the plugin ANSIescape. The only solution I managed to conjure up was to install ansifilter and use that.

$ brew install ansifilter

And, since the "cmd" tag doesn't support more than one command, and because "shell_cmd" doesn't support "working_dir", I ended up with this:

// Final version
{
    "shell_cmd": "cd ${project_path:${folder}} && ./build.sh 2>&1 | ansifilter",
    "file_regex": "^(..[^:]*):([0-9]+):?([0-9]+)?:? (.*)$",
    "syntax": "Packages/Makefile/Make Output.sublime-syntax"
}

Note that when using the "shell_cmd", it create a shell for each build. So if you do something time consuming things in your bash startup scripts, it will take extra long time to build in Sublime as well.



You can read more on the subject here

Command line Arduino builds

Now that I have the Arduino up and running, I knew I wanted to use my editor of choice and command line build tools.

There is of course the alternative of using the Arduino IDE as a command line tool, but it still felt too clunky for my needs.

Secondly, there is the Arduino Makefile project, which would be a better fit, was it not... you know... make. And I saw a few results for CMake when googling, don't get me started.

So, again, I set out to create my first built scripts.
I looked at these instructions and changed it slightly for my needs. I also looked here.

$ brew tap osx-cross/avr
$ brew install avr-libc avr-gdb
$ brew install avrdude --with-usb

After that, I looked at the verbose output from the Arduino IDE to figure out most settings. And I also compared them to other packages (Arduino-make etc).

In the end, I got this build.sh

Monitor

To communicate with the Arduino (e.g. displaying the debug output), I use "screen" on osx (On windows there's PuTTY).

You quit "screen" with ^A+K:

$ screen /dev/cu.wchusbserial1410 9600

Foot note:

I compared the turnaround time between my script and Arduino-make:

./build.sh:

$ time ./build.sh
real 0m3.264s
user 0m0.185s
sys 0m0.100s

Arduino-make:

$ time (make -f ../Makefile && make -f ../Makefile verify_size reset do_upload)
real 0m6.275s
user 0m1.224s
sys 0m1.120s

That's 3 seconds longer. That's going to get annoying real fast! Of course you get a ton of extra features, but I just don't need them.

How to map your Parallels Desktop folder into OSX

A simple reminder for me how to do this:

$ ln -s /Users/mawe/Documents/Parallels/Windows\ 10.pvm/Windows\ Disks/C/msys64/home/mawe/work /Users/mawe/work/win10

My first Arduino

I recently got hooked by the game Shenzhen I/O which I've played and enjoyed a lot with my friends. And, after a while, I got curious about learning some (really) simple electronics. So I picked up a subscription to TronClub. But, after a little while, my coding brain wanted to skip to the fun stuff: Creating something that was really working and useful in very few bytes, and also to get to do some soldering!

So, I got onto www.aliexpress.com and ordered some components, first of which arrived today was my new Arduino Uno (or rather a $3 knock off from China). Installing the Arduino IDE was simple enough, but getting it to talk to my arduino was not so simple.

I'm using a mac, and those security settings can be a little bit in the way sometimes. In this case, it seems the USB protocols didn't support the china boards usb chips. Luckily, after much hassle (I won't mention those details, to not confuse the instructions for you), I found this driver that worked for me, by just installing:

https://blog.sengotta.net/signed-mac-os-driver-for-winchiphead-ch340-serial-bridge/

After installation, I rebooted and restarted the Arduino IDE, and now, voilà, the "Tools -> Ports -> Serial Ports" lists "/dev/cu.wchusbserial1420" as a proper port. And now I can upload new sketches.