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Interfacing SAA7103 encoder with PXA255 board running windows CE

Hi all,

I have an Intel PXA255-based board running Windows CE. I have been asked to generate NTSC TV output from this board. For this I have been asked to use Philips SAA7103 encoder. According to the datasheet, the SAA7103 is capable of converting Digital RGB signals into NTSC or PAL output. As the Windows CE BSP that I am using already has a Display driver which is meant for LCD displays directly connected to PXA255, I would prefer to tweak the existing driver just enough to drive the Philips encoder. How easy would it be? What are the things I should watch out for. For the record, the LCLK of PXA255 is 100MHz and the display resolution

640x480 @ 8bits per pixel.

I believe the primary issue is interfacing PXA255 with SAA7103, therefore I am asking this question here (Instead of WinCE newsgroups).

Thanks, Vishveshwar

Reply to
vishveshwar
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I don't think that it is that easy. That board puts out what is effectively VGA which is not interlaced and double the line rate of NTSC. Your pixels will arrive in the wrong order at the wrong rate. I doubt that you will be able to tweak the display drivers to change it. So you are going to need to grab the frame and scan convert it. For NTSC it will be hard, for PAL even harder. I'd just buy an external scan converter.

Peter

Reply to
Peter

The SAA7103 encoder chip is supposed to convert non-interlaced VGA output to PAL/NTSC. Anyway, I have been able to slap together some code to program the encoder from within the display driver. Now I have a very unstable NTSC video available. I can see the WinCE desktop and can move around but the display shakes violently everytime something happens. I have currently programmed the encoder as per the calculations/formulae given in the SAA7103 datasheet (available at:

formatting link
However, since I do not have much experience with display/video programming, I do not know how to proceed.

Vishveshwar

Reply to
vishveshwar

I am using the following settings for the SAA7103 encoder: Input resolution: 640x480 pixels Input type: 8-bit indexed colour pixel. (input format 5) pixel clock: 25MHz (since 25MHz and 12.5MHz were the only possible valid frequencies) Encoder Xtal: 27MHz (recommended by philips)

Vishveshwar

Reply to
vishveshwar

Sorry, I hadn't checked the datasheet. That chip is indeed a video scaler and it should do what you want. I'd start off by looking very closely at the waveform on a 'scope and see if it matches the ones in these images:

formatting link
formatting link

There are a lot of settings to check.

Peter

Reply to
Peter

Thanks for the pointers. Let's see if I could arrange a 'scope! Meanwhile, I am checking out the display on a TV tuner card on my PC, as out here in India we use PAL system for TV. Do you think using a TV tuner card is a good idea? Will it cover up some deficiencies of the video output that may be exposed when a real NTSC TV is connected?

Vishveshwar

Reply to
vishveshwar

Thanks for the pointers. Let's see if I could arrange a 'scope!

Meanwhile, I am checking out the display on a TV tuner card on my PC, as out here in India we use PAL system for TV. Do you think using a TV tuner card is a good idea? Will it cover up some deficiencies of the video output that may be exposed when a real NTSC TV is connected?

Vishveshwar

Reply to
vishveshwar

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