Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan > 
> yes.. thanks for replying.. twice ;-) ?
> 
> i guess it is because yahoo is really lame with the postings..
> huge delays everywhere today...
Yep, the first reply took 4.5 hrs to post, the 2nd reply beat the 
first one by a couple of hours.  --Strange, must be an artifact of 
the clustered databases/stored procedures.


> As said in the other post i have problems with the 300dpi of the 
printer,
> uneven pad spacing. try to tweak it, or buy another printer. how 
much dpi 
> do you have?

Uneven spacing is the aliasing from your 300dpi printer, even at 
600dpi, it's there, but much less of an issue.  You can see a little 
of it on the 48pin tqfp on my website photo of the raw copper with 
the newly tranfered image.

My LJ 5L is a 600dpi --I'd like to get a newer 1200dpi, but this one 
works good so even the $79 (after rebate) printers you see at a lot 
of stores now is hard to justify.  If I didn't already have one 
though, it'd be a no brainer.

I have done some work with  HP III, IIp with OK results --but no 
tight traces --also the toner on that one was a little more brittle --
3rd party refillable.  I don't think 300dpi is up to doing .5mm pitch 
tqfps though.

 
> i bought:
> 9 xc95144-10
> 2 xc95216-15
> 2 AD9801 (25 Msamples ADC)
> 2 ADSP2181 KS-160
> 1 ADSP21061 KS-160

> payed 30eur which is what one xc95144 would cost me otherwise.
> 
> 
Sounds like a pretty good deal!  Also, Xilinx online store has some 
better prices than a few of the electronics vendors that carry thier 
products.  If you ship outside of the US though, shipping costs kill 
the deal.

> First project with them is a freq. counter using one cpld and 
having all 
> leds of the 7segm. display
> connected to a individual output. i know this is simply mad without 
> scanning etc. but i have
> the I/O and i am mad. I hope to programm it in a way to display 
freq. or 
> period duration
> because my scope has no readout and this would be nice.. i also 
will try 
> to allow for
> t_low and t_high measurement. (if i fund a suitable input stage).

You could hook an oscillator to the CPLD and muliplex some of the LED 
drivers; although with that many pins, as you say, you might not have 
to.  I'd probably pulse the outputs anyway to reduce how much power 
you were sinking into the CPLD's.  These little devices are pretty 
cool.  Much more reliable than the AMD variant pal-gal 22v10's we 
used in school.  Although, they don't breadboard too easy.  ;')

Anyway, sounds fun.  :')