vsdev » Misc

JTAG Wiggler Schematic Fix

vsergeev — Fri, 16 Feb 2007 00:17:29 +0000

Per has brought to my attention that the JTAG Wiggler schematic on the “JTAG Wigger Clone” page has an error. I jumbled up the P4/P3 connections on the parallel port when I was adapting the schematic in EAGLE (the schematic is based on this one http://jtag-arm9.sourceforge.net/circuit.txt). I have fixed this error in the JTAG Wiggler schematic image, and I also posted the EAGLE schematic file.

Thanks to Per for bringing up the error.
I apologize for this mistake and I’ll do my best to look out for them in the future.

New E-Mail Messages Checker with 7-Segment LED

vsergeev — Tue, 01 Aug 2006 22:35:28 +0000

The other night I came across a 7-segment LED display and decided to interface it to a parallel port. I added a button as well. The 7-segment LED lines (each leg of the display plus the dot LEDs) are connected to the parallel port data pins (D0-D7). I have the button hooked up to nInitialize (bidirectional) and nAck (input only). I’ve never done a parallel port interface project before, so I figured this would be a good start.

I wrote some quick prototype software in Perl, of all languages. It requires Device::ParallelPort for parallel port access, which for some reason didn’t work well with writing data bytes, so I had to resort to doing everything bit by bit in software. For the switch, I bring nInitialize down, and poll nAck for changes. When nAck goes low, the switch has been pressed.

Actually the idea from the start was to make a New Message email checker on my desk. I’d like to be able to press a button and get a report of new email messages on the LED display. I achieved exactly that with the Mail::POP3Client module for perl. It works well, but for some reason I couldn’t get IO::Socket::SSL working in Windows ActiveState perl, so it doesn’t work with POP3 servers where SSL is required (Gmail). Other than that, it works perfectly.

If there are more than 9 new messages, it displays a 9 with the dot, otherwise it shows the number of new messages on the LED display. When it is connecting and checking the email, only the dot is displayed. When there is an error connecting or retrieving the number of new messages, an ‘E’ character with a dot is displayed. I would record a mini video demo but I just can’t seem to find a parallel port cable extension.

Pictures:

If you would like to take a look at the Perl code, feel free to download it here: POP3 New Messages Checker with 7-Segment LED in Perl

MiniLA Kit Arrived

vsergeev — Sat, 22 Jul 2006 06:07:04 +0000

Yesterday I received the miniLA kit (mini logic analyzer, see more at http://minila.sourceforge.net) from g1powermac.
Some info from a previous post:
“”g1powermac” from the ##microcontrollers IRC channel on Freenode has organized a group PCB and components buy of the “miniLA” mini logic analyzer, freely available at http://minila.sourceforge.net/ . This will be an invaluable tool for FPGAs and CPLDs, which I’m looking to getting into. The device itself has some very impressive features: 32 channels, 100MHz, 128Kb memory for *each* channel, compatible with 3.3v and 5V, and it is of course free. The price will probably end up being under $70 as well. There is also a simple parallel port to USB converter designed for the miniLA, and it looks relatively easy to build.”

Currently there are none available to order, but check periodically because a second run with an improved board is coming along soon.

Here is a picture of it unassembled: