there is "CBUS optimization setting" in your document "ADV748x_Recommended_Settings_PrA_2014-08-20.pdf".
MHL CBUS OPTIMIZATION SETTINGS The following two writes should be included in the configuration of the ADV748x in MHL mode in order to optimize the CBUS operation:
• Reg 0x03[6:5] in the CBUS Map must be set to 0b01
• Reg 0x0A[7:0] in the CBUS Map must be set to 0x61
where can i find these 2 register about MHL CBUS optimization ? there is no description about these in your ADV7481 Reference Manual "ADV7481_UG-747.pdf".
is there any other document about ADV7481 MHL setting ?