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ADV7623-P and Bypass_Audio_Passthru

Question asked by caw97 on May 20, 2014
Latest reply on Jun 2, 2014 by mattp



We're using the ADV7623-P (non-HDCP variant) in a design and we are trying to "inject" audio into the HDMI_Tx stream.  However, the audio seems to always be in passthru mode, regardless of what value we write to Rx_HDMI_MAP register 0x3C (BYPASS_AUDIO_PASSTHRU).  ie We can write 0x12 or 0x02 to Rx_HDMI_MAP 0x3C and in either case the audio gets passed through.


Is there another register or setting that overrides the BYPASS_AUDIO_PASSTHRU bit?


We are trying to inject 24-bit 48kHz 2-channel I2S (left-justified) audio via AP1_In (pin 76), using AP5_In (pin 70) as the LRCK, SCLK_In (pin 69) as the bit-clock and MCLK_In (pin 68) as the master clock.  Master clock = 12.288MHz.  Everything looks good at the corresponding pins, but the Tx audio is always the same as the Rx audio and not what we're injecting.


Any help is much appreciated.  Thanks!