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DS90CF386: Did DS90CF386 support a format 1280*720p@60hz？

Jeckson lee
Intellectual 280 points
Part Number: DS90CF386
Other Parts Discussed in Thread: DLPC3435

Hi TI team

I have a question, did the DS90CF386 support  revceive a resolution 1280*720p@60hz which ODCK is about 74.25Mhz.

I noticed the datasheet support list do not include it

this is the datasheet description: Supports VGA, SVGA, XGA, and Single Pixel SXGA///  20-MHz to 85-MHz Shift Clock Support

I find all these supported format is a 4:3 format, not a 16:9?

thanks!

  • 0
    TI__Mastermind 22986 points

    Hi Jeckson,

    Thank you for the question. Actually, the availability of image would be determined by PCLK (total pixels * refresh rate), not aspect ratio. I think it is available since the desired PCLK is in the DS90CF386 pixel clock range.

    Regards,

    Josh

  • 0 in reply to Josh Baik
    Intellectual 280 points

    Hi Josh

    Thank you for your answer，why I asked such a question，because I have a related problem about this .

    We use a DS90CF386 to receive lvds from SOC ，transform LVDS TO RGB888 to DLP chip DLPC3435 （support 1280*720p@60hz max），this is the condition.

    when we config the SOC to output a 1280*720p@60hz resolution to  DS90CF386，we find the  screen  will not display all the size of it，as the picture shows below：red  rectangle shows

    then we use an oscilloscope to probe the HSYNC/ DE/ DATA（R0）；this is the result：

    Blue ：HSYNC /  Purple ： DE/    Yellow ： R0 DATA， 

    we find that when DE goes low ，there is a blank data area before it ，

    then we use a 1024*768p@60hz resolution ，we find the horizontal screen can display all as the picture shows below：

    （ the vertical is still not ocupied full as the red rectangle shows）

    also we probe the the HSYNC/ DE/ DATA（R0），the result shows below：

    Blue ：HSYNC / Red ： DE/    Yellow ： R0 DATA， this time we find  DE and DATA will horizontal align and the screen can show all horizontal pixel

    So we still doubt that DS90CF386 is suitable for 4:3 format ，and can not translate a 16:9 format normally？？

    Thanks !

  • 0 in reply to Jeckson lee
    TI__Mastermind 22986 points

    Hi Jeckson,

    Jeckson lee said:
    1280*720p@60hz which ODCK is about 74.25Mhz.

    Could you clarify that blanking is considered PCLK 74.25MHz since 1280*720*60 is ~55MHZ?

    Regards,

    Josh

  • 0 in reply to Josh Baik
    Intellectual 280 points

    Hi Josh

    Thank you for your help，Yes， I think blank is considered. 

    this is the 1280*720p@60hz parameter：

    #timming

    h_active=1280
    v_active=720
    h_period=1650
    v_period=760
    hsync_width=40
    hsync_bp=110
    hsync_pol=0
    vsync_width=5
    vsync_bp=25
    vsync_pol=0

    the clk= 1650*760*60 =74.24Mhz

  • 0 in reply to Jeckson lee
    TI__Mastermind 22986 points

    Hi Jeckson,

    1. Could you clarify that you are using 386 or 366?
    2. Could you provide the color depth (bits per pixel) ?
    3. There is big difference between h_period and h_active. hsync_fp (front porch) seems to be too much as 220. Could you try again with reducing hsync_fp and h_period? 

    Regards,

    Josh