Proto Board Question

Paul Sr. · 2007-12-20 15:52

I finally got around to plugging in my Proto board (with accessory kit installed) and tried out the VGA Hi-res demo. I get nothing on the screen. Demo board works fine with the same program.

Is there anything special about the Proto vs. the Demo that I might have missed? Looks like it should work.

Thanks,
Paul

Ken Peterson · 2007-12-20 16:16

There are a few resistors on the Proto board that you need to add in order for VGA to work. Did you try running anything else on the Proto board to verify the Propeller is working?

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The more I know, the more I know I don't know.· Is this what they call Wisdom?

Rayman · 2007-12-20 16:51

There's a power switch too... You do have a green LED on, right?

Paul Sr. · 2007-12-20 17:12

Resistors come with the accessories kit and are installed - and yes, the switch and LED are on.

Actually, I did just try a couple of other things and now I suspect the Prop is not working - ID's and downloads fine but doesn't seem to be actually running code. I put the scope on a pin that should have a signal and there's nothing home!

Thanks.

Paul Baker · 2007-12-20 17:43

Can you post the code you are using?

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

deSilva · 2007-12-20 18:02

When the propeller LOADS a program it is running!
Main issues are generally crystal clock and PLL.... Try to run a program in RCFAST mode!

Paul Sr. · 2007-12-20 18:16

Paul

The VGA code I used is right out of the Object exchange (untouched) - VGA HiRes Text (works on my Demo board)

The LED code is PushbuttonLedTest.spin from the PE-Lab-Setup-v1.1.zip (untouched)

Ken Peterson · 2007-12-20 18:58

A colleague of mine had this happen with two or three demo boards. The program would download, but no action on the pins. Replacing the Prop (or using a different demo board) was the only thing that worked.

If you have a DMM handy, you might want to check for shorts and continuity on your solder connections.

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The more I know, the more I know I don't know.· Is this what they call Wisdom?

Rayman · 2007-12-20 19:08

I think if it ID's and downloads code, it's probably OK...· Maybe try something simpler:

  'This is the favorite minimal code of forum user "deSilva"
PUB main      
  DIRA := -1       'This sets all pins for output 
  REPEAT           'Starts a repeat loop
     OUTA++        '  that increments the OUTA (pin ouput) register
                   'So, pin#0 will toggle at the clock frequency
                   '  and pin#1 will toggle at 1/2 of clock frequency
                   '  ... pin#n will toggle at 1/(2^n) of clock frequency

Use your scope to see if pins are toggling...

Or, there's a VGA "Hello World" app here:
http://www.rayslogic.com/propeller/GettingStarted.htm

PS:· The crystal just pops off the board.· So, you might break/make connection there.· Also, with the crystal out, it's easy to check continuity to the prop X pins...· I think the code posted above doesn't use the external crystal, so if that works, maybe it is a crystal issue..

Post Edited (Rayman) : 12/20/2007 7:16:27 PM GMT

Paul Sr. · 2007-12-20 19:46

Rayman,

Thanks for the code - much simpler when you are troubleshooting to have some simple canned apps!!

Pins are toggling fine.

"Hello World" - nothing!

I have examined the board (i.e. all of my soldering) and everything looks fine. Although all of the joints appear to be clean with no shorts (I'm not a rookie) I probably need to go at it with my DMM. What a PITA! Didn't plan on having to troubleshoot the board!

Appreciate the advise.

Paul

Rayman · 2007-12-20 20:06

Sounds like it's either a soldering issue with the VGA connector/resistors or a crystal issue...
Try putting this:

CON
 
  _clkmode = xtal1+pll16x
  _clkfreq = 80_000_000

At the very start of deSilva's code and see if the pins still toggle (much faster now...)

Mike Cook · 2007-12-20 21:03

So far out of 12 ProtoBoards;

I've had one hard failure; will identify and program but will not display anything with the TV object. That's all that was installed on the NEW board, the three resistors for the NTSC TV out. Board worked for less than a day and then no TV output. Emailed Parallax and offered to send it in for analysis, but no takers. Believe this to be PLL failure. Pitched the board, did not want it mixed up with good boards.

Failure last night with NEW board that was running a Xbee module. Again new board out of the bag, soldered four wires to a socket to plug a Zbee module in. Programmed the board and it worked fine for 3 days. Got home last night and no transmissions. Did several tests as outlined in the above responses, all worked. Reloaded the Xbee test program (5th or sixth time), then it started working as it did when I originally set it up, changed nothing in the program or on the ProtoBoard itself. Will keep an eye on this one. This thread has pictures of this board, about the 10th post down.

http://forums.parallax.com/showthread.php?p=695092

All power supplies are either good lab units, or powered by 4 known good, D-Cell alkaline batteries.

I also have 4 or 5 others loaded with various stuff, SD, TV, serial, GPS you name it. These have not been babied or abused, these have been just fine over the last few months. Seems to be very robust.

Wonder it this could be 'crib death'? Don't get me wrong I've been perfectly happy with these ProtoBoards. Just a little cautions because of these two experiences.

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Mike

Paul Sr. · 2007-12-20 21:45

Rayman said...
Sounds like it's either a soldering issue with the VGA connector/resistors or a crystal issue...
Try putting this:
CON 

  
  _clkmode = xtal1+pll16x
  _clkfreq = 80_000_000
At the very start of deSilva's code and see if the pins still toggle (much faster now...)

They do NOT!

I took the crystal out and pushed it back in - seemed to be tight in the socket.

Paul Baker · 2007-12-20 21:46

In that case your PLL did give up the ghost.

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

Paul Sr. · 2007-12-20 22:02

I tried another crystal with the same results.

Rayman · 2007-12-21 00:46

You might be in trouble then... Fortunately, a new proto board is only ~$20. Unfortunately, I bet the Norcomp connector is a pain to desolder. Just for the heck of it, you might try checking continuity from the crystal plug pins to the Prop pins...

I was able to replace the chip on one of my Proto boards (because I was too lazy to desolder all the stuff I had put on it). But, it wasn't easy and not all the pads survived... But, since the chip is about the same cost as the Proto board, I wouldn't recommend that for a bare board...

Proto Board Question

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