Bug Katcher on Agnus

I swear I already posted about this but heck if I can find the post.  Anyways, here’s a photo of a bug katcher installed on Agnus on a Commodore Amiga 500.

This gives me the ability to attach a logic analyzer to Agnus which is normally difficult because of the PLCC package that Agnus uses.  You insert the bug katcher into the PLCC socket on the amiga motherboard, and then plug agnus into the katcher.  You can then attach the logic analyzer leads to the labelled (very nice) pins on top of the bug katcher. And speaking of labels, how cool are the HP logic analyzer leads that are also color coded and also labelled with the numbers.  In both cases, this really helps prevent making mistakes when hooking up the test equipment.

The one I’ve got is here.

http://www.emulation.com/pdf/F4535.pdf

bug_katcher_installedbk_in_action

EEVBLOG does a video teardown on the Amiga 500!

Dave just posted this! I’m so glad to see him take this on!

http://www.eevblog.com/2013/03/13/eevblog-438-amiga-500-retro-computer-teardown

Bought a HP 16700A logic analyzer

So I recently bought an HP 16700A Logic Analyzer which is a large mainframe type unit. It has (3) 16715A modules in it capable of a total of 200+ channels of logic analysis at up to 667mhz.

I’m pretty happy with the unit and built an equipment cart to support it.

Information on the HP unit can be found here.

equipment_cartPictured here is the top shelf (an Amiga 500, of course) on an anti-static mat.  There’s a monitor arm for moving around the 20″ LCD. I have added a cherry G84-4100 keyboard and a trackball so I have more room on my sliding keyboard shelf that I built. The Logic Analyzer itself is on the second shelf, and room for storage etc is on the bottom.

The equipment cart was made out of 2×2 solid poplar, with birch-veneered plywood for the shelves.

The HP is network connected with built in web-server for remote control, FTP, and is a full fledged HPUX system in itself.

David Partridge’s site has useful information. As does the HP agilent yahoo group.

This is easily the most powerful and capable logic analyzer that I own, and I’m glad to have added this tool to my arsenal. I’m currently working on a soon to be released, but in BETA a project involving the A500.

my mini-review of the IKALOGIC Scanalogic-2 PRO logic analyzer

As many of you know, I maintain a comparison page of sub$1000 logic analyzers here.  I previously owned both a LogicPort and a Saleae Logic unit.

I just received in the mail an IKALOGIC Scanalogic-2 PRO logic analyzer.  This is a small low-cost($79 via MCPros) logic analyzer which is about half the price of an 8-channel Saleae Logic.

The rough specs on the unit are:

  • 4 channels (both for input, and for output (signal generation))
  • 20 million samples per second
  • 256K samples per channel
  • Multiple serial decoders for SPI, I2C, 1-WIRE, UART, CAN, LIN,Manchester
  • Multiple voltage support: 2V, 2.8V, 3.3V, 3.6V and 5V logic
  • Free Windows-based ScanaStudio software

It ships with the following stuff:

* the small blue unit itself

* a multicolor 5-port lead with micrograbbers(including GND)

* a 3-ft USB cable

* a quick-start ~4″ x 6″ card

 

 

 

My source for the specs, manual, software, etc can be found at IKALOGIC’s site here.

The two screws holding the small plastic case together make it super tempting to pry inside and see the hardware that the scanalogic-2 is based on:

As is with the Saleae Logic unit, the 5-port lead that includes the micrograbbers isn’t polarized or keyed in anyway, which could lead users to accidentally connect ground to something they were trying to measure.  They did include a “Probes Legend” in the Configuration / Device tab to help show the proper orientation of the cables.

I connected the SL2 (I can’t keep using the full name) to my Commodore Amiga, specifically the DENISE chip, to test it out.  I hooked it up to two clocks, one called 7M on the YELLOW and CCK (color clock) on the BLUE lead.

Here’s an image of it in use: (Click for full size)

The micrograbbers were nice and attached quickly and securely.

The software ScanaStudio installed with no problems on my Windows 7 machine, and recognized the hardware as soon as I connected it without driver related problems.  The software itself seems pretty clean, intuitive, and looks relatively well-designed.

IKALOGIC made the design decision to use the mostly driver-less HID class to interface the SL2.  While this makes installation a breeze and limits driver issues, it also slows down the maximum transfer rate which means that post-acquisition, there is a delay of about 30 seconds before the data is displayed on the screen.  The wait isn’t too bad, but other devices on the market are near-instantaneous.

The device works as advertised, and the software behaves as you would expect.

Here’s a screenshot of the SL2 in action:

In the above image, I recorded two clocks being provided to DENISE and then highlighted a section by selecting it.  It shows the total time of the selection, the frequency, and duty cycle.

The software has some useful features like the ability to export a screenshot, export the data to CSV, export printer-friendly images, and so on.  The triggering is simple (Falling, Rising, or Logic Change) on either ALL channels or an individual channel.  There is also a neat auto-refresh mode where the device will periodically go out and make another acquisition.

I didn’t really play with the signal generation capabilities or the various signal decoders yet.

I contacted support for a couple minor issues, and the email response was lightning fast and addressed my issues completely…..

Overall, this is a small straight-forward, low-cost unit, which could help in many hobby projects.  If you need to take a quick look at an SPI bus, or help debug a small interface, this could come in really handy.

 

progress on amiga vsc made this weekend, VSYNC problem persists

Worked on the Amiga VSC this past weekend at Notacon with my super smart friend Brian P.  We made some progress, including eliminating all but the smallest HSYNC related bugs.

There is still a problem that is haunting us with VSYNC where the screen is shifting up and down constantly.  We have not uncovered a clue to what the problem is despite many theories and attempts.

I’ll post a picture and new video soon.

 

Cause of most of my noise is likely a sample error

I haven’t put much time lately into the amiga VSC but I put in a little tonight.

I’ve got the image cleaner than it has been, but there is still noise on the left hand side, and a left-center band of scrolling red dots.

These dots are sampling error for sure because when they occur, usually the two samples that I take don’t agree.  I should be able to get more than one 10ns sample of a 140ns data, and so perhaps something is drifting until it gets onto a signal boundary, and then comes back again.  I’d like to see this in the data itself, so perhaps I need more captures.

I submitted the current code to the SVN repo….

 

Video artifacts present in scan doubled video

I uploaded a video to youtube that shows some video artifacts happening with the scan doubled video.

The entire video shakes as if interlaced, but it’s not. Original res 320×200(15.7khz), doubled to 640×400.(~31khz)

There is a colored wavy pattern across the white sections.

Video showing artifacts

On a monitor directly attached to the amiga, the screen is very stable, crisp, and nice looking. :)

 

Removed the black bar, amiga VSC is starting to work much better

Here’s a screen shot of the amiga vsc in action.  As you can see, there’s been much improvement from the last session.

Even though I am now passing the amiga’s VSYNC through the FPGA to the monitor, I wasn’t resetting my Y coordinate in my hvsync generator module. What this meant was that the module thought it was blanking when it wasn’t — spitting out a scrolling black bar.  On receipt of a VSYNC from the amiga, I now adjust the Y coordinate appropriately. (set it to 435, for what it’s worth)

 

 

Getting closer….

So a few versions later, trying some different failed attempts, I am finally starting to get a little closer.  Here’s the best video I’ve got so far, but my image is still scrolling.

If I can fix the scrolling issue, which I suppose is related to VSYNC, then maybe things might be looking better.

The things that give me hope are:

  • Size is basically correct, taking up the whole output screen.
  • Colors all look right
  • Text is basically readable
  • Some artifacts around the edges of the graphics, but nothing too horrible

Yay! Initial shots from the VSC!

So I got everything hooked up tonight, and the good news is that I have definitely made some progress!

It appears to work, although the video is currently scrolling with multiple video problems, but I definitely have something to work with!