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HDMI

vineet kumar
Intellectual 730 points

hi 

i am presently working on Spectrum digital 816x/389x EVM . I am very new to this field. I have gone through the pdf of HDMI . Through them i can make out that with the help of sysfs and character driver we can change the display resolution and know about the status of the HDMI. But what if i want to display some image on the HDMI?

I tried alot going through the wikipage of the HDMI. but i didn't find anything like displaying a string and image on the HDMI Screen.

please help me out.

  • 0
    TI__Guru**** 477635 points

    Hi Vineet,

     

    You could use FBdev to display any RGB image on HDMI. Please go through the sample application to know how to display.

     

    Regards,

    Brijesh Jadav

  • 0 in reply to Brijesh Jadav
    Intellectual 730 points

    Hi Brijesh

    I have gone through the /dev/fbo files. from there i came to know about the fixed screen and variable screen . with the help of ioctl command i am able to make the hdmi blank. but i am not able to find any ioctl command with which i can directly display an image on the HDMI.

    would you please tell me the links of the FDev application you are referring to.

  • 0 in reply to vineet kumar
    TI__Guru**** 477635 points

    Hi Vineet,

     

    Fbdev works differently, it allocate the buffer at the time of init and it will display that buffer continuously. You could change the start in the buffer PANDISPLAY ioctl. So if you want to display an image, you will have to copy this image into this buffer. this buffer is mapped into the application using mmap system command. Please go through it.

     

    Regards,

    Brijesh Jadav

  • 0 in reply to Brijesh Jadav
    Intellectual 730 points

    Hi Brijesh

    would you please tell me why there is a need to change the start in the buffer using PANDISPLAY IOCTL.  Also once the fbdev buffer is mmaped on the application space how to copy the image on to that buffer.As i am very new in this segment what i think is there is a need to change the image into some raw format and then copy it to the fbdev buffer. if this is the case how we can convert an image into raw format.

    please help me out

  • 0 in reply to vineet kumar
    TI__Guru**** 477635 points

    Hi Vineet,

     

    Can you try memcopying you RGB88 image into mmapped buffer and see if it displays something?

     

    Regards,

    Brijesh Jadav