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TAS2557: Audio Interfaces in DSP Mode

Ryan.Bishop
Expert 3900 points
Part Number: TAS2557

Hello,

The customer will be using the TAS2557 in DSP mode and we have a couple of questions on the audio interfaces.

  1. Can we use just the ASI1 audio interface for open loop control?
  2. Is there more documentation on the icc/ASIM port?
  3. What is the function of the icc/asim port and how does it differ from asi1 and asi2?

Thank you!

Ryan B.

  • 0
    TI__Mastermind 20085 points
    Hi Ryan,

    1) You can explain me in detail your application to understand you much better.
    2) We don't have a documentation on the ICC/ASIM port.
    3) The ICC/ASIM port is used to communicate two SmartAmps in Stereo Setup and the ASI1 and ASI2 are used to set an input digital audio signal.

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer
  • 0 in reply to José Luis
    TI__Expert 3900 points
    Thank you Jose.

    1. We intend to use 8 of these amps on one DSP bus. By open loop control we mean that we do not need processed audio feedback from the amp on ASI2.
    2. Understood, thanks.
    3. Is the ICC port also required for DSP mode?

    Regards,
    Ryan B.
  • 0 in reply to Ryan.Bishop
    TI__Mastermind 20085 points

    Hi Ryan,

    1) Time-division multiplexing (TDM) is required for two or more devices to share a common bus. TDM mode is useable with DSP interface mode. You can refer TDM mode section the SmartAmp's datasheet to find further information.
    3) No, it isn't. As I mentioned the ICC/ASIM port is just used to communicate two SmartAmps in Stereo Setup.

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer

  • 0 in reply to José Luis
    TI__Expert 3900 points

    Hi Jose,

    Thanks again for your help on this. I had a follow up question on this same opportunity:

    Before we finalize the research board schematic we want to confirm.
    Will it work if the customer has 16 of these amps in TDM mode with 16-bit audio even though the last bit will be in the 256th bit position?

    ASI PCM Mode

    ASI1_FORMAT[4:2] = 0x1

    ASI2_FORMAT[4:2] = 0x1

     

    ASI PCM Input Word Length

    ASI1_FORMAT[1:0] = 0x0

    ASI2_FORMAT[1:0] = 0x0

     

    ASI OFFSET1

    ASI1_OFFSET_1 = 0xF0

    ASI2_OFFSET_1 = 0xF0

    Regards,
    Ryan B.

  • 0 in reply to Ryan.Bishop
    TI__Mastermind 21260 points

    If we assume a starting offset of 0, then the MSB and LSB positions should be as follows:

    Channel MSB LSB Offset
    1 0 15 0x0
    2 16 31 0x10
    3 32 47 0x20
    4 48 63 0x30
    5 64 79 0x40
    6 80 95 0x50
    7 96 111 0x60
    8 112 127 0x70
    9 128 143 0x80
    10 144 159 0x90
    11 160 175 0xA0
    12 176 191 0xB0
    13 192 207 0xC0
    14 208 223 0xD0
    15 224 239 0xE0
    16 240 255 0xF0

    This should just fit within a word frame sampled at 48 KHz with a 12.288 MHz BCLK.  Is the customer planning to use the SDOUT lines of these devices?  If so, care should be taken to setup the bus keeper so that there isn't conflict between the devices.  Also, only 16 bits of data would be available per device.  

  • 0 in reply to Ryan.Bishop
    TI__Mastermind 20085 points
    Hi Ryan,

    You could verify the answer If this helps you to resolve your problem. This is useful for other customers with the same problem.

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer