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PCM1865: Audio Data Interface timings for TDM Slave mode

Stephane Le Provost
Prodigy 20 points
Part Number: PCM1865

Hello,

The datasheet provides only the audio timings for 2 channels in 7.11 with tBCKP min = 1 / (64 × fS).

This is not fast enough for the TDM 8-ch described on Fig. 46 which requires tBCKP = 1 / (256 × fS). (Per datasheet "The frame rate in TDM mode fixed to 256 BCK per frame")

Also tLRCP min = 10us is not enough to support 192kHz.

What are the complete timings (including tCKDO and tLRSU) for TDM at 192kHz and 256 x fS? 

Thanks,

Stephane

  • 0
    TI__Expert 5645 points

    Hi Stephane,

    Welcome to e2e Forum.

    The timing requirement table for the SLAVE mode is bit confusing and we do have some exceptions as applicable to the min/max timing for TDM mode in section 9.3.16.3 in the revised version of the DS. In this section, we cover the TDM mode in more detail and below comment -

    "The timing limits for the interface signals are defined by the Serial Audio Data Interface Configuration section with the addition that the BCK period minimum must at least 1 / (512 × fS) to ensure that data is clocked in correctly".

    Thanks & Best regards,
    Ravi

  • 0 in reply to Ravi Patil
    Prodigy 20 points

    Hi Ravi,

    Do you mean that there will be a new revised version of the DS with more details added? Current 9.3.16.3 is "Digital Audio Output 2 Configuration" in Rev D then 9.3.16.4 on TDM doesn't describe the detailed timings I'm looking for (steup, hold, ...).

     My understanding for TDM is that 256xfS ratio is required in PCM186x so BCK has to be exactly 1 / (256 x fS). "BCK min at least 1 / (512 x fS)" would not be a sufficient condition. Is it not the case?

    Thanks,

    Stephane