Hi group
Part1 :
This really was a demanding project.
I already populated the Usb part of the circuit and wanted to test it, but unfortunately there was a short between ground and the 3V3 rail. I suspected it was a bad solder joint and searched for it with a microscope,
but I could not find it. In the end I had no choice but to remove all already components. It was an act of desperation. Sometimes you introduce a short, you can't see because the solder crept under the component.
Everything removed and inspected, guess what, the short was still there,...
When I flipped the pcb, it struck me like lightning, there were etching errors on it.
http://http://www.flickr.com/photos/12416978@N06/5670610581/
After fixing these the shorts were gone and the matrix was ready for a restart.
Part2
When I build a new circuit, I like to reuse as much components as possible.
Not because I am a cheap stake (at least not only) but because I like the idea of reuse.
I usually visit a junk yard once a month and salvage some pcbs from there.
Here is a pic of pcbs I used for the bus blaster.
http://http://www.flickr.com/photos/12416978@N06/5671816011/
The most important tool when working with smd parts is a LC meter.
I bought this one a while ago and love it, it is very accurate and works down to a pico farrad without any troubles.
http://http://www.flickr.com/photos/12416978@N06/5672382698/
Part 3
After all shorts gone, I started to repopulate the board.
Guess what, it worked from the first try, I introduced no errors, unbelievable, considering the fine pitch of the ft232.
So why going through all this hassle and not buying a populated board from seedstudio ?
For me this board has a kind of personality, I spent hours to bring it to live, every time I will work with it, it will remind me I successfully tamed the monster.
This board is definitely not suited for a beginner, the ft232 is a bitch to solder and bug hunting might cost hours. I would suggest to buy one and ask Ian for a Cpld board, which are much more simple to solder but they still are a challenge.
Ian thank you verry much for this board and all your support.
I love the work you are doing here.
Finally a picture of the completed board:
http://www.flickr.com/photos/12416978@N06/5671816489/ (http://www.flickr.com/photos/12416978@N06/5671816489/)
Unfortunately the area around the ft232 is a bit messy, because I had to solder it twice.
I will try to clean it up, now that it is working.
Cheers
Rubi
Here some output when working with Urjtag:
UrJTAG 0.10 #1869
Copyright (C) 2002, 2003 ETC s.r.o.
Copyright (C) 2007, 2008, 2009 Kolja Waschk and the respective authors
UrJTAG is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
There is absolutely no warranty for UrJTAG.
jtag.c:518 main() Warning: UrJTAG may damage your hardware!
Type "quit" to exit, "help" for help.
jtag> cable ft2232 interface=1
Connected to libftd2xx driver.
jtag> bsdl path c:bsdl
jtag> detect
IR length: 8
Chain length: 1
Device Id: 00000110111000011100000010010011 (0x06E1C093)
Filename: c:bsdl/xc2c32a_vq44.bsd
jtag> svf c:\JTAGkey.svf stop progress
Parsing 660/663 ( 99%)
Scanned device output matched expected TDO values.
jtag>
Seems to work perfectly.
LG
Thanks for the update, congratulations on a successful build, despite hardware defects.
Thanks, I plan to build Bus Blaster v2.5 as well, and your experience will definitely help.
Thank you
But the board problems are an exception, Ian told me he never had that before.
Cheers
Rubi
No, no, we've had that before :) In the past we played really loose with the separation on a few projects and got burned. McZ had a FT232 LCD backpack that was messed up in the same way. Since then we've been really careful about leaving a large separation. This board seems good separation on the top, but maybe we forgot to adjust the bottom layer from the default.