Charleston master oscillator & misc

[Martin]

1.  A few of us were talking about this over Tacos and I think there's
sufficient interest in a group order.

3.  I've been learning to program FPGAs too.  I've been going though some of
the on-line classes and Pong Chu book.  I've played around with some of the
Xilinx reference designs like the frequency counter/generator.  I've toyed
around with Xilinx's PicoBlaze microprocessor and OPENIDE for software
development on the PicoBlaze. I've built Conways "Game of Life" with VGA
out.

6.  I'd like to learn more about FPGA programming and working with a group
would be fun.  Adding function to the Charlestown radio would be a
worthwhile goal.

Martin


On Fri, Jan 14, 2011 at 1:52 AM, Terry Fox <tfox at knology.net> wrote:

> Here are updates on a few items:
>
> 1.  I finally got around to replacing my temporary replacement of the
> 76.8MHz programmed oscillator on the Charleston Receiver board.  I had
> ordered a couple custom CMOS SI570 running at 76.8MHz.  I am PLEASED TO
> REPORT that the phase noise issues that I had been trying to fix for quite a
> while ARE COMPLETELY GONE!  Those of you following the SoftRock saga know
> about the SI570, a programmable oscillator from SI Labs.  You can order the
> SI570 to come at your own start-up frequency, plus it can be programmed to
> any frequency in its range via an I2C bus interface.
>
> If you want to order SI570s to replace your older oscillators, they are
> about $13 each, plus shipping.  I suggest group orders wherever possible.
>  The custom part number that SI Labs assigned to my SI570 setup is:
> 570AC000729DG.  It usually takes about 4-6 weeks for custom orders, which
> can be placed via the SI Labs website.
>
> I installed my SI570 in the same place as the original oscillator.  The
> SI570 has some extra pads, two of which are the I2C lines.  In order to
> connect wires to them, I used some small SMT zero-ohm resistors as small
> standoffs to put the oscillator above the board.  I actually soldered the
> four 0-ohm resistors to the four corner pins of the SI570, and then a couple
> small wire-wrap wires to the I2C pads.  Then, I placed the oscillator with
> the resistors on top of the original oscillator pads, and soldered it in
> place.  I then ran the extra wires to a small four-pin header, with the two
> outside pins bent over and soldered to the ground plane on the underside of
> the board.
>
> 2.  James Ahlstrom, author of Quisk, has a nice article in the latest QEX
> regarding a digital SDR HF transceiver.  It uses an FPGA, A/D, D/A, and
> other stuff.  This is the type of radios that I am interested in, in the
> long run.
>
> 3.  I've been messing around more with FPGA programming, learning this
> stuff.  I have a 12-bit A/D & D/A system passing data through themselves.
>  Next, I plan to tap the A/D samples and feed them into a buffer and
> graphics converter.  I also have the VGA output of the Nexys2 board creating
> a 640x480 display with a 10x10 grid inside it, like an oscilloscope.  The
> hope is to create a simple oscilloscope using just the FPGA board and a fast
> A/D.  That is the first "end-product" toward building a panadaptor using the
> Charleston receiver.
>
> 3.  Toward the oscilloscope project, I also purchased a quad 8-bit A/D,
> 100MHz board from Joe Rothweiler of Sensicomm.  It actually has only two of
> the four A/D positions populated, but it appears to work.  His software is
> geared toward PC display using Linux & Octave.  It only does a single-shot
> grab & display right now.  While that is interesting, I want to use the FPGA
> VGA output instead.  His board plugs into the Nexys2 large FX2 connector, so
> the hardware is compatible.  He is also finishing up a design that has two
> 8-bit A/D & a smaller FPGA on a single board.  Google Sensicomm if
> interested.
>
> 4.  I also have been playing with small TFT LCD displays.  I have a 4.3inch
> 480x272 display running with the Nexys2, it's plugged into the FX2
> connector.  More recently, I found a 5.6inch, 640x480 TFT LCD on ebay, and
> have successfully made it work with the Nexys2 FPGA board, also interfaced
> via the FX2 connector.  The 10x10 'scope-like display works with it in
> addition to a standard VGA monitor.  The "Truly" 480x272 display was less
> than $50, but you can also buy replacement 480x272 PSP displays for about
> $25 on ebay.  The 640x480 TFT LCD costs more, about $50, plus another $25
> for shipping (I think).  Most of these displays come from China.
>
> 5.  I also purchased a Xilinx-compatible USB JTAG programming cable on
> ebay, also from China.  It costs about $59.  I can use it to program the
> Sparkfun Xilinx FPGA board, or the Digital Shortcut FPGA board.  I no longer
> need to worry about finding parallel ports to do taht jtag programming.  I
> tried to buy it from "hummingosand", but it never showed up.  Thank goodness
> Paypal has protection against that type of thing.  Beware of this vendor,
> check the feedback!  I ended up buying one from hongkong_electronics, and it
> showed up promptly.
>
> 6.  Is anybody else doing FPGA work?  Is there interest in creating a group
> of simple sessions to help beginning FPGA programming?
>
> 73s
> Terry
>
>
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