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How to use AM3517's 5-ch McBSP implemented 8-ch I2S audio

taylor_891229
Prodigy 100 points
Other Parts Discussed in Thread: AM3517, PCM1608, PCM1609A, PCM1681

How does to generate 8-ch audio via AM3517's McBSP interface,

and McBSP's pin-out mapped to 8-ch I2S.


Thanks you!

  • 0
    TI__Mastermind 28055 points

    Can you give me a little more detail on what you are trying to connect to the AM3517?

    Thanks

      Paul

  • 0 in reply to PaulM
    Prodigy 100 points

    We want use AM3517 to design 8-channel tone audio generator that audio code using PCM1608.

    How to connect both AM3517's McBSP and PCM1608.

    thank you!

  • 0 in reply to taylor_891229
    TI__Mastermind 28055 points

    Connecting the PCM1608 to the Am3517 would require the use of 4 McBSP modules. Each McBSP module would drive one of the DATAx inputs with left and right channel data.

     

    It would be necessary to have one McBSP act as master transmitter and the other 3 as slave transmitters. The master would supply the clock (BCK) and frame sync (LRCK) to all the slaves and the PCM1608.

     

    Since BCK and LRCK need to be synchronous with SCKI you could use either SCKI or SCKI to drive the CLKS input of the master McBSP.

     

    However, loading on the pins may be an issue. In addition, the PCM1608 is not recommended for new designs, PCM1609A is the recommended replacement.

     

    A better option may be to using something like PCM1681 if it supports your system requirements. It can use TDM to transfer all 8 channels of audio data using a single McBSP.  Not only do you only require 1 McBSP you also reduce the routing requirements.

     

    In all cases, remember to use a series resistor next to the McBSP master output clock.

     

    Audio options can be found at http://focus.ti.com/apps/docs/appcategory.tsp?appId=1&DCMP=TIHomeTracking&HQS=Other+OT+home_a_audio

      Paul

  • 0 in reply to PaulM
    Prodigy 100 points

    Pual thanks your reply!

    I be think using TDM for audio, but only PCM1608 approved  in my company.

     

    As follows some question, thanks your reply!

    In slave-transmit used only "Dx"  that others signal is don't care?

    Pual can you provide sample codes or programming step for McBSP 8-ch i2s?

  • 0 in reply to taylor_891229
    TI__Mastermind 28055 points

    The slave transmitters need to be connected to the FSX and CLKX of the master. The slave DX signals go straight to the DAC.

     

    I’ve created a small example program on the EVM which connects McBSP3 (master) and McBSP4 (slave) and sends out incrementing/decrementing data in I2S format - enables 4 channels. The connection can be scaled using 2 more McBSP modules to support 8 channels.  

     

    I’ve attached the Code Composer 4 project which contains all of the source files.   

  • 0 in reply to PaulM
    Prodigy 40 points

    Hi.

    Just a little questio. In your source you enable the "GPIO5 I clock" and "GPIO5 F clock", why?

    Thanks.

    Regards.