4x8 DSP using two ADAU1701

The Dayton DSP-408 has two ADAU1701's to make it a true 4x8 DSP.  How would I be able to do this on my own?  I have the Sure APM2 that has a ADAU1701.  Is it somehow possible to transport audio between two APM2's to increase the in/out count? Thanks!

Parents
  • 0
    •  Analog Employees 
    on Aug 12, 2019 2:03 PM

    Hello Mark,

    You just have to connect the two serial ports together so they will send audio data to each other. One will be the clock master and the other a slave. You can use two I2S ports, but that uses up more GPIO pins, or you can use TDM-4 to send four channels between the parts. This would limit you a little or you can use a TDM-8 format and be able to fully share all channels between the two DSPs. I usually try to use the slowest clock speeds as possible to avoid issues with signal integrity and timing. As long as they are close together you can make TDM-8 work. I suggest running the clocks using a ribbon cable with ground between each clock on the ribbon. So for BCLK, LRCLK and SDATA lines in both directions you would need an 8-way ribbon. 

    You also will need to use the same master clock for both boards. So this would be yet another signal to jumper between the boards. 

    Dave T

Reply
  • 0
    •  Analog Employees 
    on Aug 12, 2019 2:03 PM

    Hello Mark,

    You just have to connect the two serial ports together so they will send audio data to each other. One will be the clock master and the other a slave. You can use two I2S ports, but that uses up more GPIO pins, or you can use TDM-4 to send four channels between the parts. This would limit you a little or you can use a TDM-8 format and be able to fully share all channels between the two DSPs. I usually try to use the slowest clock speeds as possible to avoid issues with signal integrity and timing. As long as they are close together you can make TDM-8 work. I suggest running the clocks using a ribbon cable with ground between each clock on the ribbon. So for BCLK, LRCLK and SDATA lines in both directions you would need an 8-way ribbon. 

    You also will need to use the same master clock for both boards. So this would be yet another signal to jumper between the boards. 

    Dave T

Children