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AD1940

Question asked by rwalborn on Aug 9, 2011
Latest reply on Aug 10, 2011 by rwalborn

I am designing a system with a AD1940 controlled off a Pic24F microcontroller.

For testing the hardware, I have a simple 4 in 4 out schematic, no processing, no volume controls.  Straight in straight out.

 

I a have a 12.288 MHz master clock, with 4 inputs input 48 k 24 bit left justified.

 

The board is 4 layers and the signal integrity looks good.

 

I verified I can read and write to the SPI Port. However, after initializing everything, downloading the code, I get nothing on any of the serial outputs.

 

The only thing I have found odd, is when  read from the DSP Core control Register ( 2642), I get a one in bit 14 which is a reserved bit. The one is also set for bit 9.  If I write a 0x00 to (2642) , when I read it back , there still is a one in bit 14. I can read and write to other registers.

 

Does anyone know what these reserved bits are for?

 

So far I can not figure out hat is wrong whether it is software  or hardware.

 

Does anyonw have any good advice ?

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