TMS320DM8168: 480i Support for on-chip HDMI port

Hi,

Can anyone from TI reply to the above mail?

Regards

Ayusman

Hi Pavel,

Thanks for the reply.
The clock mentioned for NTSC is 216MHz in the structure entry for vmode_info[] as mentioned by you.
However the clock output needs to be 27 MHz for 480i on HDMI with pixel repetition as per the HDMI standard.

Can you please clarify on the same. Have I missed anything. How do we set the HDMI to give 27MHz clock with pixel repetition.

Regards
Ayusman

Ayusman,

27MHz display pixel clock is required for 480p resolution (not 480i).

linux-2.6.37/drivers/video/ti81xx/vpss/sysfs.h

/*480P*/
{"480p-60", FVID2_STD_480P,
{FVID2_STD_480P, 720, 480, FVID2_SF_PROGRESSIVE,
27000, 60, 16, 60, 62, 9, 30, 6},
TI81xx_MODE_HDMI
},

Regards,
Pavel

Pavel,

I understand that the HDMI clock frequency can be upto 165MHz frequency. Also from the below link,

http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/717/p/292258/1019272?tisearch=e2e-sitesearch&keymatch=%20user:120910

It is mentioned that the 480i timings you had shared does not work. Can you please recheck.

Also can you please confirm if you have tested 480i on on-chip HDMI port of DM816x with a HDMI standard analyzer.

Regards

Ayusman

Ayusman,

No, I do no tested on my side.

For any detailed software support, bug fixes, or enhancements to this software, please contact any of the select partners recommended below.

e2e.ti.com/.../426680

Regards,
Pavel

Hi Pavel,

Thanks. Can you share what registers I need to set if I want to use clock doubling feature for on-chip HDMI?

Regards
Ayusman

Pavel,

For HDMI, the minimum clock rate needs to be 25 MHz. Now for resolutions like 480i (which runs at RGB 24-bit @ 13.5 MHz) the clock is doubled to 27MHz and also each pixel is repeated.
Please see this link below as example. I cannot post from HDMI standard here.
allpinouts.org/.../

Also in the /drivers/video/ti81xx/ti81xxhdmi/hdmi.c file in linux kernel I see that there is mention of pixel repetition as a comment. I have gone through the code but I believe it does not enable and use pixel repetition.

Also I see that in the TRM on page 1166, there is mention of clkmult_ctl bit in HDMI PHY register which mentions to be used for multiplying the clock when pixel repetition is needed.

Request you to please check the following and help me figure out how we can use this feature.

Regards
Ayusman

For any detailed software support, bug fixes, or enhancements to this software, please contact any of the select partners recommended below.

e2e.ti.com/.../426680