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DM6446 andTVP5150: PAL vertical synch

manisha sa
Prodigy 80 points
Other Parts Discussed in Thread: TVP5150, TVP5150AM1

Hi,

I am using DM6446 DSP processor.The TVP5150 is used for capturing interlaced PAL and NTSC data.  We have a requirement that the application should automatically detect the input video standard.

When the input source is set to either PAL or NTSC standard, the TVP5150 is able to detect it correctly. 

However, when the video input is changed from NTSC to PAL when application is running, the vertical synch is not present and hence we are not able to determine the input standard.  This is also observed when we change the input from PAL to NTSC.

The values in the TVP5150 registers while switching input video standard from NTSC to PAL are:

For NTSC:
REG 136 (88h): 0x000e
REG 140(8ch): 0x0081 //To determine the video input
REG 192(c0h): 0x00c0
REG 193(c1h): 0x0000
REG 194(c2h): 0x0004


For PAL:
REG 136(88h): 0x0002
REG 140(8ch): 0x0081
REG 192(c0h): 0x0040
REG 193(c1h): 0x0000
REG 194(c2h): 0x0004

 

We are initializing the following registers initially,

REG 3 (0x03): 0x29

REG 13 (0xd): 0x40

REG 15 (0xF): 0x02


Please let me know the reason for this behavior. Please help me resolve this issue.

Thanks in advance,

Manisha

  • 0
    TI__Genius 15310 points

    Hello Manisha,

    Could you please give me the setting for register 28h?  If it is not 0, can you change it to 0 to enable autoswitch?

    Are you using our latest patch version v048CAA?  You can tell by reading the version number from registers 82h and 83h (ROM is 04h and 00h).  If not, please use this patch v048CAA to improve the video performance.  You can download patch and doc from here:

    http://software-dl.ti.com/dsps/dsps_public_sw/dsps_swops_houston/ANALOG_VIDEO/Analog_Video_Decoder_Versions.htm

    Regards,

    Viet

  • 0
    TI__Genius 16810 points

    Manisha,

    REG 8Ch should be 81h for NTSC and 83h for PAL.  It appears from your register data that the TVP5150AM1 is not properly switching to PAL.

    Do you have REG 28h set to 00h?  This enables autoswitch.

    If you start off in a good PAL state, does REG 8Ch  stay set to 83h when you switch the source to NTSC?

    If you start of in a good NTSC or PAL state, does the system properly recover if you disconect and reconnect the cable?

    Are you using firmware patch code with the TVP5150AM1?

  • 0 in reply to Larry Taylor
    Prodigy 80 points

    Hi,

    Yes, the REG 28h is set to 00h.  

    when I start with good NTSC or PAL, the system behaves correctly. even if I disconnect and reconnect the cable, everything works. fine.  However, when I switch from NTSC to PAL or vice a versa, the vertical synch is not present and the video standard remains unchanged.

    I am not using the firmware patch code with the TVP5150AM1? I am only using TVP5150 driver.

     

    Thanks & Regards,

    manisha

  • 0 in reply to manisha sa
    TI__Genius 15310 points

    Hello Manisha,

    Do you see any thing on video after you switch?  Can you read registers 28h, 82h, 83h, 88h, 89h, 8Ah, and 8Ch after you remove NTSC input and plug in PAL and send them to us?

    Regards,

    Viet

  • 0 in reply to Viet Dinh
    TI__Genius 15310 points

    Hi Manisha,

    Can you read those registers couple second after you plug in PAL?

    Regards,

    Viet

  • 0 in reply to Viet Dinh
    Prodigy 80 points

    Hi Viet,

    Please see the values of registers:

    First when NTSC standard is selected:

                                                                                                                 
    REG 0/40: 0x0002                                                                                                                
    REG 0/130: 0x0004                                                                                                               
    REG 0/131: 0x0000                                                                                                               
    REG 0/136: 0x001e                                                                                                               
    REG 0/137: 0x0008                                                                                                               
    REG 0/138: 0x001a                                                                                                               
    REG 0/140: 0x0081

    when switched to PAL

    REG 0/40: 0x0002
    REG 0/130: 0x0004
    REG 0/131: 0x0000
    REG 0/136: 0x0012
    REG 0/137: 0x0008
    REG 0/138: 0x0018
    REG 0/140: 0x0081


    Another read for PAL standard

    REG 0/40: 0x0002
    REG 0/130: 0x0004
    REG 0/131: 0x0000
    REG 0/136: 0x0002
    REG 0/137: 0x0008
    REG 0/138: 0x0018
    REG 0/140: 0x0081


    After switching back to NTSC

    REG 0/40: 0x0002
    REG 0/130: 0x0004
    REG 0/131: 0x0000
    REG 0/136: 0x001e
    REG 0/137: 0x0008
    REG 0/138: 0x001a
    REG 0/140: 0x0081

     

    Please let me know if you need more information,

     

    Thanks & Regards,

    Manisha

  • 0 in reply to manisha sa
    TI__Genius 15310 points

    Hello Manisha,

    The reason for autoswitch is not working because the register 0/40 (28h) is setting to 02h.  Please set it to 0h to enable autoswitch (please read it back to confirm it is 0).  The default setting for this register is 0 so you can just comment out the writing to this register from your back end.

    Regards,

    Viet

  • 0 in reply to Viet Dinh
    Prodigy 80 points

    Hello Viet,

     

    Thanks for the information.  After setting the value 0 in 28h register, I am able to auto detect the PAL and NTSC   We were forcefully writing the  desired video standard in reg 28h. When this is removed and the 28h is initialized with value 0, everything worked fine.

     

    Thanks once again for your help.

     

    Regards,

    Manisha