Has any one played with a STV5730A video overlay chip

[Darrel Taylor]

Sphere

I have, and I can say that you'll need to spend a LOT of time in the datasheet. Much more than a normal PIC datasheet. It's not layed out very well.

Can't give out any of the code, but here's one from the Old List...
http://list.picbasic.com/forum/messages/5820/6314.html?

or, here's one for sale.
http://www.blackboxcamera.com/stv5730a/software.htm

Also, I don't think they make those anymore, so if you want to build a bunch of them. You might want a different chip.
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[Sphere]

Just had a look at the code, is it not possible to use shift out instead, it would make it a bit simpler to follow. Ive read about the chip being discontinued do you know of a equivilant chip.

Thanks for the reply Sphere.

[Darrel Taylor]

Yeah, you can shiftout, but it's pretty slow at only 50khz (4mhz osc). The chip can be clocked at up to 2 mhz. Although that routine won't go that fast either.

Don't know of any alternatives.
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[Ron Marcus]

There is NO equivalent IC out there. For that reason, I had to make an OSD board using two '819s a gated oscillator and video sync chip to do the same thing. It was a PIA, but won't go obsolete any time soon. There are some simple circuits posted on the web to do this. This was a starting point for me, but I needed higher res,smaller characters, and three lines of 20 char read out! The gated oscillator was the tricky part, and mine runs at 28MHz to make it all work as planned.
If you find an alternative chip, let me know...
Ron

[Sphere]

Thanks both for the replies. I already have a stv5730a in a working circuit, so I give the code example a go and see how far I get. Ive googled around looking for an alternative but no joy so far. It looks like all current video generation is done via a microprocessor plus software rather than a specific chip.

Thanks again Sphere..

[mister_e]

BOB-3 or BOB-2 modules spring to mind but they'r not cheap.

This week,, and Alain posted a link her on wich you can find some plug and play solution.

http://www.speechchips.com/shop/

Now you just have to figure out how to mix the signals together.

Those solution are simple, but you should stock them... i guess one day they'll disapear... as many other ics anyways

As now i used PICs @20MHZ and LM1881, great to me as now.

EDIT: and this dig-out a really old thread...
http://www.picbasic.co.uk/forum/show...ghlight=lm1881
i knew it reminded me something

[Sphere]

I did look at the BOB-3 BOB-2 modules but as you said its all down to cost. Ive had some success with the code for STV5730A, give me a few more days and I will have it cracked. This project is more for myself than production.

Thanks Sphere..