Loop Back Test - Sticky?

madworm:
Is it safe to assume that newcomers will know that they should look for how to perform a 'loop back test' when uploading doesn't work?

No.

The title of the sticky post doesn't say anything about failing uploads.

What should the title be?

What introduction (cover) should be added? Perform a loop-back test when...

draythomp:
Actually, after the revisions suggested above, this is really good.

Excellent!

The only thing that struck me was that when I first saw it I asked myself, "What do I want to do a loopback test for?" Perhaps, something about why one would/should do a loopback test?

I agree. One case is: uploading was working, upload is not now working, damaged processor is suspected. When else would / should a loop-back test be performed?

radman:
I tried the procedure and had no difficulty following it.

Excellent! Thank you.

The slight change I wanted to suggest was that some of the text in step 8 should be removed

Nope. Not going to happen. My Tech-Com II professor stated repeatedly: You tell it to them three times. You tell them what you are going to tell them in the introduction. Then you tell them in the body. Then you tell them what you told them in the conclusion. After working in technical support for a few years, I strongly agree. Some people get it the first time they read something. Some people barely get it the third time they read something. Troubleshooting instructions need to be written for the latter group; lots of repetition.

and instead there should be a short introduction saying why you would do the test and what it would achieve

I agree. It needs an introduction / cover.

Suggested text at the start (removing equivalent text in point 8 );

The loopback test will prove that your host computer hardware driver, USB cable, and USB to serial converter are all working.
Try the loopback test after you first install the system or if you cannot upload sketches.

Is it necessary to perform a loop-back test after first installing the system?

Is it necessary to perform a loop-back test after first installing the system?

No. The loop-back procedure is a troubleshooting aid/procedure to help one determine if serial communication between the PC and Arduino board is working or not working in a typical arduino installation. It does no harm to run it on a working system, and it would probably be best to learn to run it on a working system before having a problem to prevent false positive (or is it false negative?) testing results.

Lefty

Is there really just one use-case? "uploading was working, upload is not now working, damaged processor is suspected"?

How's this for the introduction...

The loop-back test is a troubleshooting procedure to determine if serial communication between the PC and Arduino board is working in a typical Arduino installation. The test proves that the host computer, hardware driver, USB cable, and USB to serial converter are all working.

How's this for the introduction...

Needs a comma between "host computer" and "hardware driver". It is testing all 4 items.

Thanks! Done.

So treat everybody like dummies because there might be one or two in a dozen !
How did the dummies get into your professors class?
When I went to uni it was stay up or get out

Not everyone that needs repetition is a dummy. Some folks read this board in their second or third language. Some folks use google translate to read it. Some folks are beginners at everything electronic. Like it or not, repetition works. It gives the person a second chance to hear it, it gives the translator a new version to try and screw up differently and it helps to reinforce information.

Besides, being snide doesn't help.

The current state of the introduction...

We have one use-case.

Should the sticky include references to example / related topics? Some examples...

http://arduino.cc/forum/index.php/topic,75651.0.html

Any more comments before I change the sticky?

I like the introduction. Short, and to the point.

I have mixed feelings about the examples, they might confuse more than help. I'll bow to other's opinions on that.

Good job.

Introduction added.

Any more comments about examples / related topics?

Any other use-cases?

Should try without the jumper as the Terminal program could have a ECHO turn on
Patgadget

There have been issues with 'clone' boards lately.

They didn't come with either the ATmega8u2 or the FT232R, but with some IC by 'Prolific'. Suffice to say people were still trying to install the FTDI drivers or the .inf file, depending on what their clone pretended to be.

Maybe there could be a note/hint to check the vendor/product IDs if the 'Arduino driver' refuses to install.

Addendum:

Of course we could say "why should we care?", but in the end people with these modified clone boards end up here and we spend our time that would be better spent elsewhere.

"Force the processor to remain in reset by connecting a jumper from RESET to GND"

How do you do this? Have any pictures :slight_smile:

Put a piece of wire in the header pin labelled Reset, and the other end in one of three headers pins labelled GND.

There's no picture of the wire!

Before a wire can be used, it must be properly declared and defined.

Well, this explains the test but not what to do when it fails, so its really not an explanation at all

@stargazer2050: If you would like help or to affect a change you will have to provide more information.

not even stickey

OSX 6.5.8 (fresh install)

Board 1 -- Arduino Mega Failed loopback test
Board 2 -- Arduino Mega Failed loopback test
Board 3 -- Arduino Uno Failed loopback test
Board 4 -- Arduino Uno Passed loopback test

Arduino 1.0

I have three boards which are no longer working: They were working fine at least 12 hours ago:

all three failed the loopback test. One did not even register with a usb serial connection.

This has been tried on at least 3 computers so far

any advice would be helpful