Benchmarking USB transfer speeds

boards

[Paul Stoffregen], creator of the Teensy series of microcontroller dev boards, noticed a lot of project driving huge LED arrays recently and decided to look into how fast microcontroller dev boards can receive data from a computer. More bits per second means more glowey LEDs, of course, so his benchmarking efforts are sure to be a hit with anyone planning some large-scale microcontroller projects.

The microcontrollers [Paul] tested included the Teensy 2.0, Teensy 3.0, the Leonardo and Due Arduinos, and the Fubarino Mini and Leaflabs Maple. These were tested in Linux ( Ubuntu 12.04 live CD ), OSX Lion, and Windows 7, all running on a 2012 MacBook Pro. When not considering the Teensy 2.0 and 3.0, the results of the tests were what you would expect: faster devices were able to receive more bytes per second.  When the Teensys were thrown into the mix, though, the results changed drastically. The Teensy 2.0, with the same microcontroller as the Arduino Leonardo, was able to outperform every board except for the Teensy 3.0.

[Paul] also took the effort to benchmark the different operating systems he used. Bottom line, if you’re transferring a lot of bytes at once, it really doesn’t matter which OS you’re using. For transferring small amounts of data, you may want to go with OS X. Windows is terrible for transferring single bytes; at one byte per transfer, Windows only manages 4kBps. With the same task, Linux and OS X manage about 53 and 860 (!) kBps, respectively.

So there you go. If you’re building a huge LED array, use a Teensy 3.0 with a MacBook. Of course [Paul] made all the code for his benchmarks open source, so feel free to replicate this experiment.

Python on a microcontroller

The team at LeafLabs was looking for something cool to do with their new ARM development board. [AJ] asked if anyone had ever played around with Python, so [Dave] cooked up an implementation of PyMite and put it on a Maple board. While the writeup is only about blinking a LED with a microcontroller, they’re doing it with Python, interactively, and at runtime.

The build uses the Maple Native board the team is developing. The board has a 32-bit ARM chip with 1 Meg of RAM – more than enough horsepower to run PyMite. The tutorial for putting PyMite on a Maple is up on the LeafLabs wiki.

PyMite is theoretically able to control every pin on the Maple Native and do just about everything a regular Python distro can do. The LeafLabs team is still working on the necessary libraries for their board (although we don’t see anything on the Google code page), so right now only blinking the LED is supported. Still, it’s pretty cool to have Python in your pocket.

What Development Board to Use? (Part Two)

We asked for responses to our last Development Board post, and you all followed through. We got comments, forum posts, and emails filled with your opinions. Like last time, there is no way we could cover every board, so here are a few more that seemed to be popular crowd choices. Feel free to keep sending us your favorite boards, we may end up featuring them at a later date!

[Read more...]

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