All,Attached is my V1.0 block diagram of the A/D and D/A board in both Visio and HTML format. I've called this "Janus" after the Roman god of gates and doors (ianua), beginnings and endings, who could see both ways at once ( input and outputs :) ).
I've drawn the block diagram for the Wolfson A/D but it much the same for the others. The PCM4202 is does not have an I2C interface to set it up so we either uses jumpers, FPGA pins or an I2C I/O port etc.
A few questions:Should we use the TLV320's 30mW audio amplifiers instead of the PWM A/D'S for our audio output? That way you could connnect a pair of headphones directly to the card. Disadvantage is that we are then relient on the TI chip in the future.
Given that D/A's are very easy to implement in the FPGA should we add a few more for control of external equipment e.g. an external linear amplifier?
The TLV320 needs to run at (24.576/2)MHz - should we derive this from the FPGA or add a divide by 2 to the board so this clock does not need to pass back over the back plane?
Where should the audio connectors be located and what style should we use and/or should the signals be routed back over the backplane?
Regards Phil... VK6APHTitle: A_d and D_A
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A_d and D_A.vsd
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