Stephen's Weblog

Another week has gone by already? Well, I do at least have something to show for it.

So the thing I spent the most spare time on this last week has been designing a FPGA-based PCI card. This is something I’ve wanted to do for some time now (and have an earlier unfinished attempt that was far more complex), but I have recently encountered some inspiration for a board that will be somewhat useful, or at least interesting.

This board isn’t really much of anything special, but it will fill a specific niche, and will be sufficient to try out a lot of interesting things I’ve been thinking of in the PCI space.

So, This isn’t going to be an exceptionally impressive post, but I did collect screenshots from various stages of the board’s development, and  I’ll also discuss the design decisions behind this board.

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Hi again,

As promised, this week’s project entry is much less entertaining;

I did attempt to get this project a bit further today but distractions have taken their toll. Expect this one to come up again in the future :)

So, not too long ago I had the bright idea to build a little USB stick; My motives at the time were apparently highly questionable, so I am here about a month later with a fairly limited use USB stick

One of my major goals behind this project was to have an excuse to work out the details of USB, and try some stuff out, which I’m still doing now. Once I get that done with, I will attempt to explain just how all that works; USB is a bit elaborate, but it’s increasingly interesting and important these days, as serial and parallel ports are becoming more rare. I have another project along these lines too, but it’s quite a bit more low-level.

For this post though, I’m just talking about the hardware design of this project. (more…)

3 blog posts already, amazing – though very shortly I may have to start talking about far less interesting projects, or post less frequently. This is starting to take quite a bit of time, and I’m running out of interesting things I’ve been doing. :)
So, recently I’ve started looking into ASIC design – it’s will still be quite a long time before I can practically start thinking about trying to design my own chip, however, in the meantime some chip reverse engineering has attracted my attention.
Now, I mostly operate from a home-lab environment, and it’s not really safe to involve things like… high concentrations of Nitric acid. But, having recently acquired a decent cheap USB microscope (the Veho VMS004DELUXE USB Powered Microscope), I decided to give chip disassembly a shot for the amusement value. Given my lack of professional tools this has little potential to be really educational, but it was pretty interesting. This is a pretty picture-heavy post,  if that wasn’t clear enough already… (more…)

Another week has gone by, and it’s time for another project!

This week’s project is a little bit more complex than the last one, but it’s still pretty small. It’s a small board that drives an 8×8 LED matrix. It’s actually a pretty silly project because I only have a dozen or so of these LED Matrices around (I’m not sure I can even buy these specific matrices anymore) – I actually bought them back in 2005 – they’re 8×8 arrays of red/green LEDs. They’re organized with a common anode per row, and then red/green cathodes per column. (Davr also got some, and has a number of entries on his blog about his efforts)

Just for fun, I set out to design a board that would sit on the back of the LED matrix and make it easy to drive from a small microcontroller. My design goals were to have current drivers on the common anodes, and provide a shift register to easily configure the other LEDs. I also wanted to be able to easily chain multiple boards together to make a much longer array. (Read on for more details about the design…) (more…)

Here’s the first installment of my weekly project report thing :) Wish me luck!

So, not terribly long ago I decided it was really time to give microcontrollers another go; My history with microcontrollers in general has been a little sketchy, because not only are they pretty limited systems, but they don’t really allow a lot of creativity in solving your problems. Being mostly self-taught on ARM and x86 CPU architectures, the little 8-bit uCs generally seemed more like a pain than anything else.

However,  I was determined not to let my history deter me, and to try again. I ordered some AVR DIP chips for prototyping and a serial programming cable. Unforuntately, like so many well laid out plans, this didn’t wind up working out – not knowing too much about the AVR landscape, I had inadvertently ordered a serial programmer that requires an actual native serial port to work (it wouldn’t do anything with my USB-serial converter… And seriously, who has a native serial port around these days?)

Being incredibly stubborn and unwilling to  wait further to order yet another programmer, I decided to take matters into my own hands – After reading the AVR documentation on programming their chips (which is actually quite good), I put together a small CPLD based programmer which has served my needs. Read on for the full details…

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Well, a few days I put in an order with The Electronic Goldmine for a few parts, specificly including 4 of their Giant Display Assortments (at a cost of $20 for the 4). Well, suffice it to say I now have enough LED Displays for the next several rounds of crazy projects :)
I got a whole boatload of LED displays, and a few character LCDs, some traditional LCDs (including one with REALLY bent legs!) some VFDs, and some other stuff. On a side note, some of the LCDS/VFDs are cracked, or appear to otherwise be in non-working condition, which is sad, but really all that can be expected from a grab bag like this.
There were also a huge amount of bent pins, but that’s also to be expected, and in most cases was very easy to correct with very little effort.
Anyway, at this point I’m not sure what to do with all of these, but I’m not likely to attempt to rival kevtris and his mega-clock… need more displays for that :)
I’ve included a picture of all the displays here, as I’m sure you’re all interested by now.