TMS320DM8168: Issues with HDMI DDC interface

vincent lavigne

Part Number: TMS320DM8168

Tool/software:

Hi,

I'm attempting to implement screen brightness control through the HDMI Display Data Channel (DDC) interface of the TMS320DM8168 processor but am encountering some issues.

Unfortunately, the processor documentation doesn't discuss the protocol used on the DDC BUS. It's unclear which version of the DDC protocol it supports, or how the various registers (address, segment, offset, count) are translated on the BUS when used with the different DDC Commands.

I can use the DDC interface to retrieve EDID information from address 0xA0, and seem to receive a response from address 0x6E (the address for the monitor's Virtual Control Panel) when i send some commands, but I'm not certain if the data I'm supplying is suitable.

Please advise.

Thanks and best regards,

Vincent

11 months ago

0 Charles Tsai 11 months ago

TI__Guru**** 186746 points

Hi,

vincent lavigne said:
Unfortunately, the processor documentation doesn't discuss the protocol used on the DDC BUS. It's unclear which version of the DDC protocol it supports, or how the various registers (address, segment, offset, count) are translated on the BUS when used with the different DDC Commands.

Reading the datasheet and the TRM, it says it is compliant to HDMI 1.3a.

I don't have knowledge on DDC but it seems like a I2C interface. You might want to check if you have all the registers set up to initiate a DDC command.

Please also note that we no longer offer direct support for this device on the E2E forum. You may search the E2E forum for archived posts of previous discussions which may help address your questions. Please feel free to reach out the 3rd parties listed for additional support.