ADV748ｘ HDCP Operation

Question

Hi,all My customer is developing an HDMI device using the ADV748x and has a question about HDCP functionality. 
 (1) From ADV748x_HardwareManual_RevPrB Page 95 &ldquo;5.3.8 HDCP Support.&rdquo;, I recognize that the HDCP function is implemented in hardware. Is this correct? 
 (2) From Figures 56 and 57 on Page 96, if Key_error=1, it will be repeated infinitely until Key_error=0. Is this correct? 
 (3)Please let us know the detailed update timing of hdcp_key_error, HDMI RX Map, Address 0x04[4] (Read Only). 
 Bset Regards aimPoint

VarshiniK · Accepted Answer

Hi, 
 While HDCP is primarily a hardware-based protection mechanism, software does play a role in the authentication process. 
 Kindly ensure with below readback registers, 
 HDMI Map Reg 0x04[5]: HDCP_KEYS_READ 
 HDMI Map Reg 0x04[4]: HDCP_KEY_ERROR 
 HDMI Map Reg 0x04[3]: HDCP_RI_EXPIRED 
 Please note i f an HDCP authentication fails source will typically re-attempt authentication by resending its AKSV and An and you will therefore get an AKSV update interrupt. 
 If you are continuously getting AKSV updates, that would suggest the authentication is repeatedly failing. 
 A failing authentication would typically also result in the source not sending video, or sending encrypted video that doesn't get de-encrypted by the ADV748x. This de-encrypted video will look like a salt and pepper noise image. 
 Wait 2 ms after receiving an AKSV update before. Then check HDCP_KEY_READ and HDCP_KEY_ERROR, If no error is detected then proceed to clear the READY bit for Port A and clear the KSV FIFO, and continue with the rest of the driver flow. 
 Thanks, 
 Varshini K)

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ADV748ｘ HDCP Operation