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BT-656 8-bit output on HDMI (no video)

Question asked by ayonbajaj on Aug 1, 2014
Latest reply on Aug 4, 2014 by GuenterL

I am facing a problem in exactly identifying the registers to be configured to see the 8-bit BT 656 output on HDMI through adv7511. We have tried to see the 16-bit BT 656 output and it's working fine. We have identified some registers on adv7511 to be changed in order to ensure the 8-bit output. They are as follows (the values specified below are specifically for 8-bit configuration):-

0X15 -> format change ( 0x4 for 8-bit; for 2X clock)

0x16[5:4] -> color depth (11 -> 8 bit).

0x16[3:2] -> input style (10 -> style 1).

0x9d -> clock divide (0x64 for divide by 2, this is corresponding to the register 0x15 -> 0x4).

0xa4[6] -> clock divide enable (1).

Since, we are using embedded sync with the resolution of 576p

therefore, we have

0xD0[1] -> 1;

0xD0[3:2] -> 11

0x17[0] -> 1;

0x41[1] -> 1;

0x30 -> 0x03;

0x31 -> 0x04;

0x32 -> 0x00;

0x33 -> 0x14;

0x34 -> 0x05;

0x17[6:5] -> 0x3;

0x35 -> 0x20;

0x36 -> 0xEC;

0x37 -> 0x05;

0x38 -> 0xA0;

0x39 -> 0x24;

0x3A -> 0x00;

0xFA -> 0x0;

0xFB -> 0x0;


There are some fixed registers also:

0x98 -> 0x03;

0x99 -> 0x02;

0x9C -> 0x30;

0x9D -> 0x61;

0xA2 -> 0xA4;

0xA3 -> 0xA4;

0xA5 -> 0x04;

0xAB -> 0x40;

0xBA -> 0x60;

0xD1 -> 0xFF;

0xDE -> 0xD8;


After doing all this I am not able to see anything on the monitor. I have made the above list of register after going through the hardware and programming guide of adv 7511 and online thread on its analog output. I believe that may be I am missing some registers to be configured specially for 8 bit output. Please help me with this.