Esden's Blog - open-hardware

FLOSS-JTAG V1.0 Released and Available

Esden — Tue, 22 Feb 2011 00:00:00 +0000

Hey everyone,

As you might know some time ago I have developed a small JTAG adapter based on the FT2232H chip. I gave it the name FLOSS-JTAG as the idea was that it should be absolutely OpenSource and OpenHardware.

You can find the project at GitHub and some more info at it's random projects wiki page.

FLOSS-JTAG not only has the high speed 24MHz FT2232H chip (there are some designs based on my idea that are using a low speed version of the same chip). It provides the new standard 0.05" pitch 10 pin Cortex JTAG header as well as a TTL level serial interface on it's second interface.

I am glad to announce that I have reached the V1.0 with it. All necessary files to make your own are in the GitHub repository. But if you don't want to go through the pains of ordering PCB, sourcing parts, assembling QFN SMD packages you can also purchase it in the Joby Robotics online shop.

At Joby Robotics you get a cable assembly to connect the FLOSS-JTAG to a target. This allows you to debug and connect to targets that are difficult to reach otherwise. You also will get a cortex connector to old standard 20pin 0.1" pitch connector adapter.

The adapter is small and will make it also easier to debug targets that are difficult to reach.

You can get precrimped Molex Picoblade wires in 10 different colors at Joby Robotics too. This way you can easily build a UART cable that connects FLOSS-JTAG to a device.

I am very happy that FLOSS-JTAG is finally easily accessible to anyone who needs it.

FLOSS-JTAG works perfectly together with Openocd and Summon-ARM-Toolchain.

Cheers Esden

Open-BLDC V0.3 Hardware Based Closed Loop Control

Esden — Sun, 19 Sep 2010 00:00:00 +0000

Hi,

Good news everyone!

After again a way too long time some new news! I finally implemented hardware based commutation detection and the associated closed loop controller.

That was quite a run because of a cascade of timing and timer problems. And a very nasty compiler bug. But now it works and very well on top of that. Woohoo o/ But see for yourself in the video.

The video also shows the new implementation of the startup routine. It uses now a separate software timer. It was made possible by using SysTick as timer base and implementing the timer in software. This way it is easy to add new timers that don't need to be very time precise, as it is the case in startup, or ignite as I like to call it. :) The old implementation was using timer overflows of the commutation timer that led to nasty speed jumps while starting up and made the startup unreliable.

Next step, put Open-BLDC on a plane! :)

As always you are welcome to drop by in #open-bldc channel on freenode if you have questions or just want to hang around to follow the cutting edge development. :)

Floss-JTAG V0.1 Assembly and V0.2 boards.

Esden — Fri, 01 Jan 2010 00:00:00 +0000

Because I wanted to have a small JTAG adapter with additional UART port and a different (smaller) connector then what is available out there, I have decided to make a JTAG adapter. I chose the FT2232 USB adapter chip. This guy is pretty nice because it has a special engine inside that is supporting many different protocols. One of them is JTAG. I have released what I made as always on GitHub under the CC-BY-SA 3.0 license. There is no software needed on the adapter side so no software included. All you need is OpenOCD. It now even has a config file dedicated for Floss-JTAG. Calling for example:

#> openocd -f interface/flossjtag.cfg -f board/open-bldc.cfg

will connect to Open-BLDC using the Floss-JTAG adapter.

Building Floss-JTAG I learned a nice lesson. Always check your footprints 10x before you send the gerber files to the manufacturer!!! I had to customize the footprint for the FT2232 chip and made a mistake. The pads were not long enough so the pins had only 0.1mm overlap area. It was a real pain to solder that. I assembled 3 of Floss-JTAG using this design. Sadly only two are working.

Because of that mistake I immediately corrected the board layout and sent it out. I got the boards today. I hope that there is no other mistake hidden somewhere. :) Attached are the images of V0.1 assembly and of the V0.2 boards.

[gallery]

Open-BLDC V0.1 Fully Assembled

Esden — Sat, 08 Aug 2009 00:00:00 +0000

I finished soldering Open-BLDC V0.1 boards and took some pictures while doing so.

After connecting it to the power everything seems to work properly and nothing is burning. That is really good news.

One little thing that is bothering me. The board draws 60mA, what is a value that I expected. The 5V linear regulator gets really warm. I am not sure if that will be a problem or not. But I did not find any other problems or screwups yet, even the big MOSFETs can be soldered using a simple soldering iron. It takes some time though, because the board and the MOSFETs are monstrous heatsinks.

More news coming up as soon as I start playing around with the software. [gallery]

Open-BLDC V0.1 is alive!

Esden — Fri, 07 Aug 2009 00:00:00 +0000

I assembled the basic STM32 circuitry of Open-BLDC and it works. I also made a video showing the logic board and blinking around. I know it is a bit pointless but I love blinking LED's! ;) I wrote the software using libopenstm32.

Have fun:

Video on Youtube and here the same video on Vimeo.

While assembling Uwe and I made some photographs that I don't want to hold off either.

[gallery]

Open-BLDC V0.1 boards are here

Esden — Wed, 05 Aug 2009 00:00:00 +0000

Good news everyone! The Open-BLDC boards are on my table. If you ask me they look gorgeous. :) But decide for yourself ...

Cheers Esden [gallery]

Open-Source and Open-Hardware Multicopter platform

Esden — Fri, 24 Jul 2009 00:00:00 +0000

Over the last two weeks many things happened. I found out that there is a really open-source and open-hardware quadrocopter project in the wild. It is called booz and is part of the paparazzi project. Code and schematics just as board layouts are under the GPLv2 or later license. That is really awesome news.

This project is intended for research and universities so the boards are using BGA parts that are difficult to solder for a mere mortal, and there is some lack in documentation. That is why some other people and me started a project called openmulticopter. The basic idea is to create and maintain a completely open-source quadrocopter/multicopter platform for everyone. As a multicopter does not consist only of the control electronics but also contains parts like remote control receiver, brushless motor controllers, a frame, and so on, we tried to combine many open-source parts that are already out there. Just take a look into the wiki for more details.

Some highlights of open-source components that we have chosen so far are:

booz (the core of the platform)
libopenstm32 (firmware library for STM32 microcontrollers)
RCOPEN24 (a 2.4GHz remote control system)
open-bldc (brushless motor controllers)

We also formulated a mission statement that can be found in the openmulticopter wiki.

There is still a lot of work in front of us, but I am really happy with the progress we are making. If you are interested in contributing just drop into the #openmulticopter IRC channel on Freenode, or write an email to the mailing list.