Communication Failure

earthlingzed

I am a newbie to Basic stamp. I just got a BS2 for Christmas, and I have just tried my first basic circuit. I fear I may have fried it already.

I am using a breadboard to do my circuits and programming.

I have a 5V power regulator changing the 9V power suply before entering the BS2. I was unwittingly running the the power into the 5V out pin on the powere regulator, sending 9 V and some changin into the BS2. When trying to send my program to the BS2 in this state, it said it found no Basic Stamps. Once I realized what I was doing and sent the power in correctly (5V), the compiler program sees the BS2 but has a communication failure (it fails to download the program).

My home is someone out there that knows a lot about this can offer me a logical fix and tell me I did not just destroy my christmas present.

steve_b

You said you 'breadboarded' your circuit....and that you put the wrong voltage on the wrong pin of the regulator.

This leads me to guess that you're not using any sort of Parallax provided platform (board of education; etc..).

Did you follow the schematic for building around a stamp?

You should have a jumper across pins 7&6 on your programming port and also have a couple of capictors in there too!

http://www.parallax.com/dl/docs/prod/schem/bs2.pdf

this is the link to the schematic....you want to look at the "Host Serial Port Conneciton" part.

or look at this one too...same difference!

http://www.parallax.com/dl/docs/prod/schem/bs2revf.pdf

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Steve
http://members.rogers.com/steve.brady
http://www.geocities.com/paulsopenstage

"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."

earthlingzed

I am not using a Parallax provided platform. I am following the guidance of this book:
Physical Computing.

I am doing something very much like what is shown in this photo but without the capacitors for decoupling:



See some excerpts from the book I am following



Here is how I am trying to communicate with the BS2:



I have done some tests to check the power. I get 5V at pin 21 like I should be getting and I get 4.4V at pin 1 which I think is about right too.

How can I determine if the communication failure is from a burned up stamp and not from something else?

Post Edited (earthlingzed) : 1/4/2005 3:49:30 AM GMT

steve_b

Well, I'm pretty certain you need to use a couple of these decoupling caps....or maybe at least a hard wire in one case.
If you look at the 2nd link I gave you, the one cap goes from the ATN pin to ground.· This will help keep the pin from floating which, I believe, causes a reset on the stamp.·

Jon or allan will correct me!· Hopefully! [noparse]:D[/noparse]

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Steve
http://members.rogers.com/steve.brady
http://www.geocities.com/paulsopenstage

"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."

earthlingzed

Thanks for the advice. I will get a couple of those decoupling caps and try it out. I think from what I have read in the Physical Computing book, the decoupling was used mainly when you are working with motors to prevent blow back.

Is there a way to determine if the stamp is blown? Is it even a posibility if I measured 9V going into the stamp (stamp was getting hot and the power regulator was also getting pretty hot).

Is there a way to determine if the serial connection is bad?

Post Edited (earthlingzed) : 1/4/2005 12:24:20 PM GMT

allanlane5

Most digital circuitry needs a decoupling capacitor between +5 and GND. The reason is that digital circuitry works with a 'clock' of some kind -- thus giving you switching transients. A small capacitor (10 uF to 22 uF) between +5 and GND, close to the chip, supplies the current for these switching transients.

Now motors make even more noise than digital circuitry -- but they both need decoupling capacitors.

steve_b

If you've got a scope you can tell if there's anything coming out resembling serial data!

A meter might not give you exact readings, but would show a deflection when data goes out....like the engine light on the car (don't know what it means, but something is going on!).

The Stamp may be alright....get the power set up right and those caps and you'll be able to determine if your comms are cool!



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Steve
http://members.rogers.com/steve.brady
http://www.geocities.com/paulsopenstage

"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."

Chris Savage

Also, shouldn't there be a jumper between pins 6 & 7 of the DB9 connector?



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Chris Savage

Knight Designs
324 West Main Street
P.O. Box 97
Montour Falls, NY 14865
(607) 535-6777

Business Page:·· http://www.knightdesigns.com
Personal Page:··· http://www.lightlink.com/dream/chris
Designs Page:··· http://www.lightlink.com/dream/designs
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steve_b

isn't that for the loopback test?· Echo or some such thing!

But yes, put it in as well!

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Steve
http://members.rogers.com/steve.brady
http://www.geocities.com/paulsopenstage

"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."

achilles03

Zed,
Did you intentionally blot out the stamp in the pictures you posted? If you're using a PicAx or other microcontroller similar to the BS2 (but not the BS2), then it might require a different setup to work properly.

Dave

earthlingzed

I did not intentionally blot out the BS2 in the pics. I just got them from a source on te eweb that I have been following. My circuit is much the same.

As for the loopback test, that returning a fail message, but the echo works.
When I type in the debug window, the debug message is displayed below as well.

Can someone tell me if this is any indication that the serial connection is working?

Thanks everyone for your generous help!!

Jon Williams

Yes, it's working. Loopback is a hardware test; it allows the IDE to search for possible BASIC Stamp ports -- this is important if you have the COM setting in the IDE at Auto (if you specify the port, it's not an issue). Echo means that the BASIC Stamp module was present (and powered-up) and what got transmitted to the BASIC Stamp came back to the IDE. If you can use DEBUG and DEBUGIN, you're golden on the connection with the IDE. Note that without the caps in the ATN line that we use on our programming boards, programs like Hyperterminal will give you trouble as they put the DTR line (connected to ATN) into a state that forces the BASIC Stamp to reset.

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Jon Williams
Applications Engineer, Parallax
Dallas, TX· USA

earthlingzed

Bad news for me. I got the capacitors and placed them in my circuit and I am still getting the same response from the IDE: "Communication Failure".

The echo is still giving me a positive response while the loopback test is failing.

I am lost and unsure what to try next.

allanlane5

Put a jumper on the DB-9 connector from pin 6 to pin 7. The IDE uses this as the 'loopback' test, to verify there is a connected cable to a destination board.

The 'Echo' test verifies that the TX and RX signals are reaching the board, and being echoe'd back. I think this validates the RS-232 conversion circuit (4 transistors).