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TVP5146M2 Decoder Issue / Question

I have a project that uses the TVP5146M2 Decoder and I am having an issue or I don't seem to not fully understand why I am seeing what I am seeing.

My initialization sequence after power up:

write 00 to register 02   (set video standard = auto)
write 00 to register 08   (luminance processing, trap filter)
write 04 to register 0E  (chrominance filter)
write 43 to register 33   (10 bit 4:2:2 output format)
write 11 to register 34   (enable YCbCr output and clock output)
write AF to register 36  (enable HS and VS output)

After that I can receive image data at 60 frames /sec.  The image data is very noisy (see picture), but it has some correlation with the real screen content.



The content of Status 1 Register (3A) is constantly changing, typical values = 13, 1B, 11, 71.
It means we have Horizontal sync sometimes, but we never have Vertical sync I believe.
The input video is NTSC, horizontal scan frequency of 15.700 kHz, 280x192 resolution.  I can't foresee any issues with this except the image may be skewed off-center.

The content of Status 2 register (3B) is always 20 = signal is not weak, no color killer, no macrovision.

The content of Video Standard Status Register (3F) is 81 = the autodetected mode is (M, J) NTSC.

Register content from 00 to DF:

00 0F 00 00 23 10 00 00  00 80 80 80 00 00 04 00
80 80 80 80 80 80 55 00  25 03 00 00 40 00 04 00
07 00 01 00 15 00 00 00  CC 00 00 00 00 00 00 00
00 05 00 43 11 FF AF FF  FF 00 13 20 55 06 0A 81
00 18 0D 02 00 00 20 20  20 20 00 09 00 09 00 09
00 09 00 00 1F 1F 64 00  00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
03 00 00 19 00 12 8A 64  06 1E 40 00 00 00 00 00
51 46 00 00 00 00 00 00  00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00  00 00 00 00 00 80 00 00
00 00 1E 00 00 00 00 00  00 00 00 00 00 00 00 00
00 00 00 00 00 00 06 1B  FF 00 FF 00 00 00 00 00

Can someone please comment on anything I should check, other registers I need to deal with, or what my issue could be?  Thanks in advance for your assistance.


Henry

1 Reply

  • Not sure what "The input video is NTSC, horizontal scan frequency of 15.700 kHz, 280x192 resolution" means. What is your video source? Have you tried using a "standard" video source such as a DVD player?

    What is the target of your digital data? Which clock edge does it sample data on? You might need to invert the data clock polarity.

    Is your target configured correctly to receive the data? Can your target accept a video stream which has discontinuities that will occur when the video source is started/stopped/connected/disconnected?

    Is your target configured for the correct video format?

    BR,

    Steve

    Please mark this post as answered via the Verify Answer button below if you think it answers your question.  Thanks!