DLP2010EVM-LC: Low trigger voltage

bearattack

Part Number: DLP2010EVM-LC

Hello,

I am having issues with the trigger output of the DLP2010EVM-LC. I've connected pins 2 and 3 of J11 to get a 3.3V output. However, the output is showing a very small signal < 50mV as pictured. Any thoughts as to why the output is so weak? Could it be a bad board? The patterns from the projector are displaying without any issues.

Mike

over 4 years ago

0 Mayank Khandelwal over 4 years ago

TI__Genius 9971 points

Hi Mark,

Can you try connecting the jumper to pin 1 and 2 of J11 and check the status of trigger out signal while running internal/external pattern mode.

Regards,

Mayank

0 bearattack over 4 years ago in reply to Mayank Khandelwal

Prodigy 60 points

Hi Mayank,

I've tried this and get the exact same output. I do notice that no matter where the jumper is placed, I am getting about a 300mV baseline voltage regardless of whether the trigger is running or not.

Thanks,

Mike

0 Mayank Khandelwal over 4 years ago in reply to bearattack

TI__Genius 9971 points

Hi Mike,

Can you also try to probe trigger out 2 signal. I think there might be some soldering issue between the board and the jumper which is causing this issue.

Regards,

Mayank

0 bearattack over 4 years ago in reply to Mayank Khandelwal

Prodigy 60 points

Thanks Mayank,

The output I am probing is the trigger out 2 signal (pins 1 and 4 on J4 on the projector board). The jumper is installed at pins 2 and 3 of J11 on the main board.

I've also tried to probe trigger out 1 signal through pins 1 and 7 on J4 but get the same results.

Best,

Mike

0 Layne Jenkins over 4 years ago in reply to bearattack

Intellectual 395 points

Mike,

What kind of load do you have on the trigger signal? The open drain buffer on the trigger signal doesn't have much drive so it may help to put an external buffer on the signal depending on what kind of load you're connected to.

More about that here: https://e2e.ti.com/support/dlp/f/94/t/864450

- Layne

0 bearattack over 4 years ago in reply to Layne Jenkins

Prodigy 60 points

Hi Layne,

It's currently hooked up to an oscilloscope. The post you referenced managed to get a 3.26V signal - I'm managing only about 300mV and signal only reaching about 310-320mV.

Best,

Mike

0 Layne Jenkins over 4 years ago in reply to bearattack

Intellectual 395 points

Are you using a high impedance active or passive probe or just a BNC breakout cable?

0 bearattack over 4 years ago in reply to Layne Jenkins

Prodigy 60 points

High impedance passive. Trigger 1 is showing the correct output at 3.3V on pin 7. Trigger 2 still shows nothing on pin 4.

0 Mayank Khandelwal over 4 years ago in reply to bearattack

TI__Genius 9971 points

Mike,

Please verify one more thing - Check if your triggers are enabled by reading there statuses via GUI after you press GET button.

0 bearattack over 4 years ago in reply to Mayank Khandelwal

Prodigy 60 points

Yes when I press GET, the fields to update showing that both triggers are enabled. I am using the SET button to writ ethe changes to the board as well.

Best,

Mike

0 Layne Jenkins over 4 years ago in reply to bearattack

Intellectual 395 points

Mike,

Have you tried both termination settings on your probe? The photo shows 50-Ohm which should give you about 16mV swing but with 1M-Ohm you should see close to 3.3V swing, assuming the signal is present in the first place.

0 Mayank Khandelwal over 4 years ago in reply to bearattack

TI__Genius 9971 points

Mike,

As per your above messages, only trigger 2 is not working correctly right?

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DLP2010EVM-LC: Low trigger voltage