Video Output Options w/Propeller Demo Board

Scope

Hello Groovy People (you too Whit & erco),

I recently obtained a Propeller Demo Board and I've been wondering what works best for video output.

After using the large displays, the tiny, the colorful - whatever - what display option works best for you?

Thanks,

Scope

John Abshier

I use a Coby 10 inch TV that I picked up for $99 at the local Nebraska Furniture Mart. It is a digital TV, and also accepts composite video and VGA inputs.

John Abshier

potatohead

I really like the TV output because it's possible to use a simple USB capture device. Done that way, the propeller video and audio output, if desired, ends up in a nice window on the PC being used to program it with. Screen captures are easy, and the whole works is portable.

When not doing that, I use a small 7" TV from the 80's Picture is just great.

The few times I've used VGA output, it's nice, and for that I prefer a 1280 capable screen of moderate size. Right now, there are a ton of those being tossed into dumpsters. It's a great time to score older CRT gear.

In either case, I prefer the CRT for real output testing. They display lots of resolutions, and are generally more tolerant than the various LCD type displays most often seen now.

The capture is an exception, because it displays well on whatever computer display you are using, and it's very tolerant. Nice combination.

Finally, if you are doing simple graphics, moderate resolution, no fancy signals, LCD devices are great. If you are wanting to do interlaced video displays, or do dynamic graphics (where the graphics are drawn in more or less real time by the propeller), I recommend the CRT because there is no significant signal processing between you and the display. Seeing the true artifacts that result from things like interlace helps tune in a driver nicely. Some of the displays and TVs with video processors in them will actually clean things up, and or display something that is otherwise lousy, quite well. You don't find out about that until some other people go and run your stuff!!

(which is how I ended up using the older TV for a test round)

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Mike Green

I use an Axion 7" TV I got from Target for < $100. It works very nicely with several different video drivers including Cluso99's 1-pin Debug TV Driver. It has a wide-screen mode that looks very clear with a 64 character wide display with the 1-pin Driver's 8x8 character font.

HollyMinkowski

I often used the TV capture card in my old PC.
It was easy to feed a TV signal to it from the Prop
and you could easily capture an avi or stills. But I
don't have access to that old PC now so I just use
VGA out to an old 13" lcd that someone didn't want
anymore.

Scope

Thanks everyone

Update: 11-Jun-2010

---

I purchased this 7" TV from WalMart for $67
Viore 7" Portable LCD TV, PLC7V96

I'll report if it's worthwhile when it arrives. It seems as though all the same 7" LCD panels may be manufactured from one source?

Happy Propellering,

Scope




Post Edited (Scope) : 6/11/2010 10:45:23 PM GMT

Scope

The LCD display is receiving the Propeller demo but the bottom and top are "cut off" (there is a vacant, blank area on the display, above and below the demo graphics where there are blank pixels but nothing is being displayed)

I'm connecting from the TV output on the Propeller Demo Board to the 1/8 (?) male connector on the LCD TV.

I believe I've changed all the available settings on the LCD TV without any success.

Any suggestions to help get the entire display to show up?

Thanks in advance! [noparse]:)[/noparse]

Post Edited (Scope) : 6/16/2010 5:02:03 PM GMT

Mike Green

That is common behavior for video displays. What's happening is that many TV sets "overscan". They present a larger image by leaving off the first few lines and the last few lines of the display as well as slightly stretching out the lines themselves, starting the scan outside the display area. In the days of analog TVs, there was always an adjustment you could make to fill the display area with whatever was sent. Now, with digital TVs and digital video generators, it's not so easy to stretch or compress the image horizontally and vertically. The demo program can be modified to produce a taller image or a wider image, but then some displays would cut off actual display data. There are some timing and dimensioning constants compiled into the video driver, but they're not simple to change unless you understand how the Propeller generates video.

Scope

Thanks MG!

Mike Green said...
There are some timing and dimensioning constants compiled into the video driver, but they're not simple to change unless you understand how the Propeller generates video.

Not yet . . . getting there . . . I've enjoyed playing around w/the sample TV spin code.