scolling text overlap in example scripts

[lambda280]

Hello,

I have two VE’s, both showing the same effect with various nootropic example scripts. The overlay (graphic or text) does not sync to the video frame, and rolls through vertically and horizontally. Checked the wiring/solder joints on both boards carefully. Tried two different monitors, and two different video cameras, one with switchable resolutions. Sure I have the switch/jumper right (v-input and overlay), and tried various trim pot settings. Same result in all cases.

Attached is a screen shot – any ideas what is causing this or where to look for problems ?

Thanks for any insights!

[Michael]

Hmm. That looks like a window on a computer screen….not using a TV? How are you getting the composite video output to your computer?

This is intended for use with TVs which are much more tolerant to the imperfect sync generated by the TVout library. Some people have reported problems with USB-based video-to-computer adapters.

[lambda280]

Yes, you’re right – it is a Dell monitor. Picture in picture with a composite input in addition to VGA, DVI, S-video, etc. My first thought was it’s the monitor, so I brought the VE board to several tv’s around the house … same result. You may not be able to tell this from the picture, but the video from either cameras is solid and steady. I may have to break out the scope….what should a video signal that is appropriate for the VE board look like ?

[Michael]

If you only had one board and it was behaving this way, I’d say you had a bad solder connection, but since you have the experience with two boards, something else is going on. And you’ve tried it on several TVs….

Your sketches have both of these funcitons, right? And you are calling initOverlay() from your setup function?

// Initialize ATMega registers for video overlay capability.

// Must be called after tv.begin().

void initOverlay() {

TCCR1A = 0;

// Enable timer1.  ICES0 is set to 0 for falling edge detection on input capture pin.

TCCR1B = _BV(CS10);



// Enable input capture interrupt

TIMSK1 |= _BV(ICIE1);



// Enable external interrupt INT0 on pin 2 with falling edge.

EIMSK = _BV(INT0);

EICRA = _BV(ISC11);

}



// Required to reset the scan line when the vertical sync occurs

ISR(INT0_vect) {

display.scanLine = 0;

}

[lambda280]

Ah – that was it. I was missing the initOverlay() call. The sketch came from the examples in the enhanced TVout-VE.zip from the nootropic site. It did not have the initOverlay call, but I see sketches embedded into some of the product project pages do.

Thanks again.

[Michael]

Oh, I see. That sketch you tried is an original example from TVout and doesn’t have overlay capability. Glad you are up and running now. Have fun.

[Author]

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