Composite video for stamp!

[Marks256]

Are there not ANY circuits in this world that allow you to put stuff on a tv screen? I looked, but i can not find any. I would do a search on this site, but apparently "tv" isn't a valid search word.

Does anyone have circuit to put text on a small black and white tv? Preferably controlled by a basic stamp.

I just want to put simple text, and MAYBE some graphics(simple of course, like a few lines, nothing fancy) on my small b&w tv(like 12cm).

It doesn't need to be complicated; just so i can get some sort of communication across.

Thanks in advance!

 

[Papabravo]

Are there not ANY circuits in this world that allow you to put stuff on a tv screen? I looked, but i can not find any. I would do a search on this site, but apparently "tv" isn't a valid search word.

Does anyone have circuit to put text on a small black and white tv? Preferably controlled by a basic stamp.

I just want to put simple text, and MAYBE some graphics(simple of course, like a few lines, nothing fancy) on my small b&w tv(like 12cm).

It doesn't need to be complicated; just so i can get some sort of communication across.

Thanks in advance!

Check out author Don Lancaster and the original TV Typwriter circa 1973/1976. You'll learn a ton following these paths.

https://www.amazon.com/gp/offer-listing/0672213133/ref=dp_olp_1/105-7358239-8775665
https://www.amazon.com/gp/offer-listing/0672213133/ref=dp_olp_1/105-7358239-8775665

 

[kchriste]

Maybe not on a Stamp PIC, but there have been PIC based video games, written in assembler, made with the PIC generating the video signal directly. Check out the simple hardware that is required to do this:
**broken link removed**

 

[Oznog]

Well pulling off any sort of video is really tough for a PIC, it has to keep a regular schedule, there's not a lot of time between pixels, and there's not enough RAM to buffer much of a frame.

A Stamp has only a small fraction of the capabilities of the PIC. I would suspect it can't be used for even the simplest screen.

There was an overlay chip and a couple of people sold modules with a PIC on them that you could feed text to with a Stamp. It could actually overlay text over a video signal.

However, they were expensive and the chip it used has had availability probs. I don't know how easy it would be to find such a module now.

 

[Nigel Goodwin]

What you need is an OSD (On Screen Display) chip - you can still get the STV5730A as a kit from https://www.blackboxcamera.com/Stv5730a/STV5730A.htm. In the past I did something similar using an NEC chip, but the problem is finding datasheets for them, and the very short lifetime of the chips.

 

[Marks256]

So PIC would be the only way, huh? Well, i can do that. I think i still have them two odd PICs of mine laying around some where, and i could make a quick programmer.

Thanks.

 

[HarveyH42]

Try this link:

https://instruct1.cit.cornell.edu/courses/ee476/video/

Use an AVR chip, but good description on how it's done, code examples. Probably useful with other chips.

 

[Nigel Goodwin]

So PIC would be the only way, huh? Well, i can do that. I think i still have them two odd PICs of mine laying around some where, and i could make a quick programmer.

Your STAMP would work fine with the STV5730A, it's only a question of passing data to the OSD chip - that way you get good quality video, and can genlock over an existing video source.

 

[jpanhalt]

Also try:

1) Decade Engineeering (http://www.decadenet.com/bob4/bob4.html)

2) Smarthome.com/5151r.html

3) ZiLog.com application note AN004800-TVC1299

The latter is more on the design level; the others are more at the kit level.

 

[Marks256]

I have some old video equipment in the basement. I will run down and see if there is on on there. Chances are that they just used a microcontroller on it, but ya never know...

[edit]

Oh. I forgot to mention that the only reason i want to use a stamp is so i can understand the code. Hardware seems pretty easy, but the code is what will confuse me...

 

[Nigel Goodwin]

I have some old video equipment in the basement. I will run down and see if there is on on there. Chances are that they just used a microcontroller on it, but ya never know...

If it's got on-screen graphics it probably uses an OSD chip, the only problem is finding any info on them! - like I said, I used an NEC chip (used in Hitachi VCR's and Amstrad satellite receivers) as it was the only chip I could find a datasheet for.

 

[Marks256]

I found a video titler with some goodies in it. Among the good suff in it had a sony V7040 chip on it to encode the video.

The data sheet: **broken link removed**

Could that be easily interfaced?

 

[Nigel Goodwin]

I found a video titler with some goodies in it. Among the good suff in it had a sony V7040 chip on it to encode the video.

The data sheet: **broken link removed**

Could that be easily interfaced?

That doesn't generate the video, only encodes it to NTSC or PAL.

 

[Marks256]

yes, but isn't that what i want? NTSC or PAL?

How do you generate RGB? I would imagine it to be analog(yeah i know "duh").

 

[Nigel Goodwin]

yes, but isn't that what i want? NTSC or PAL?

Eventually, but you need the information first - OSD chips normally accept a composite video signal which passes straight through, and had the option to superimpose it's text on the incoming video, or repalce it entirely. Check the website I posted, it shows what one can do.

How do you generate RGB? I would imagine it to be analog(yeah i know "duh").

You have to generate every single part of it, horizontal sync pulse, vertical sync pulse, and all the video information in between - including your font information for any text you display. Generally you would only do single brightness characters, so just need a very simple D2A, giving sync level, black level, and peak white. You can do this fairly crudely using a PIC or AVR, but using an OSD chip does it all for you - and makes a MUCH, MUCH better job of it.