how to design a chip to encode VGA signal to TV signal?

[funster]

hello, all friends:

We want to design a chip to encode VGA signal(vsync rate

is 50hz or 60hz) to TV signal. we can only use line buffer,

any one can tell me how to design such a chip, we

now have datasheet of CH7013A and VIA1622,

but from datasheet, I don't understand how their chip

works.

I want a detailded architecture for such a chip?


The biggest problem that we encountered is

how to synchronous input vsync and output

vsync.


any comments are welcomed.


help me !!!


best regards

 

[IanP]

Maybe you should try AD722 from analog devices:
http://www.eecg.toronto.edu/~tm3/ad722.pdf
And here is an exampe of its application:
**broken link removed**
Regards,
IanP

 

[elektor]

Hi,
I designed similar design. We used ADV 7179 from Analog Devices
Very nice chip, but requires I2C for configuration.

Regards
Elektor

 

[funster]

Our chip is same as CH7013 from chrontel inc.

ADV 7179 is only a tv encoder.

we need to convert some VGA format into TV

signal (such as 640x480, 60hz; 800x600, 60hz VGA to TV signal).

I have no idea now, can you give me further advices?


best regards

Hi,
I designed similar design. We used ADV 7179 from Analog Devices
Very nice chip, but requires I2C for configuration.

Regards
Elektor