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TAD5112: Possible to select 2 of 8 TDM slots to be output?

Stephen Turner
Genius 3476 points
Part Number: TAD5112

Tool/software:

I'm considering the TAD5112 for a design.  From the reading (the complex for a DAC!) datasheet it seems like I can do the following, but would like to verify:

  • Run the TAD5112 in TDM mode using an I8S format (that's 8 32bit channels per frame, BCLK = 256 x the sample rate). 
  • FSYNC is 1 BCLK wide, audio TDM data starts on the rising FSYNC. 
  • Data is clocked out on the falling edge of BCLK and clocked into the DAC on the rising edge. 

All fairly standard stuff.

In addition, I think I can do the following:

Programmatically through I2C, select which of the 8 slots I feed to the two DAC channels, i.e Slot 1,2 or Slot 3,4 etc up to Slot 7,8.  Can I do this?.

Thanks!

  • 0
    TI__Mastermind 46615 points

    Hi Stephen,

    Yes you're correct. Each DAC channel can be mapped to any TDM slot you wish (assuming the slot exists based on BCLK/bit depth) independently of each other. It probably makes the most sense for them to be in a pair like you listed, but it could be any combo you wish.

    Best regards,
    Jeff McPherson

  • 0 in reply to Jeff McPherson
    Genius 3476 points

    Hi Jeff,

    And I'd use the PASI_RX_CH[1..8]_CFG registers for this?.  Can you explain what settings I'd use to get DAC Left output from TDM Slot 1 and Right output from Slot 2?.

    thanks!

  • +1 in reply to Stephen Turner
    TI__Mastermind 46615 points

    Hi Stephen,

    That is right. The register map starts its slot indexing at 0. I'm not sure what indexing you're using so I'll go through both.

    By default, the device already sets slot 0 to the left channel DAC and slot 1 to right channel DAC. This would be like Standard I2S where there is no slot skipping.

    If you're wanting to move these over to the right by 1 slot (one empty channel, and then the two receiving channels), you would program the below:

    PASI_TX_CH1_CFG = 0x20 = 0010 0001 to set Slot 1 on the TDM Bus to be DAC Channel 1 (this channel is mapped to DAC OUT1 by default)

    PASI_TX_CH2_CFG = 0x22 = 0010 0010 to set Slot 2 on the TDM Bus to be DAC Channel 2 (this channel is mapped to DAC OUT2 by default)

    Best regards,
    Jeff McPherson

  • 0 in reply to Jeff McPherson
    Genius 3476 points

    perfect - Thanks!