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ADSP-21479, SPORT with PCG, ADC reading

Question asked by nlsa001 on Dec 20, 2011
Latest reply on Jan 2, 2012 by Mitesh

Hi

 

I am trying to use the SPORT with PCG to control and read ADC. I set the PCG as the SPORT clock and FS, and they work as I set, and I can see the ADC sending out data at the SO line. But when I read it through the SPORT, I found the data not correct.

 

In my code writen by C, I still use the method of polling the receive buffer status (I am trying to use interrupt way, but that needs some time to me). And I read the data line three times and put them in DM for checking in the code. For easy to check the timing of the reading, I use a DAI port to set a pulse once I read the data line.

 

Following is the timing of reading the three data.

 

TEK00003.PNG

In the diagram, the blue trace is 12-bit ADC output(the value is AD5 or AD6), the green trace is ADC clock, the yellow tarce is the ADC's converter control (FS), the purpul one is the pulse I issued after read a data.

 

You can see in the diagram that the reading time is not correct (except the first one), and the three read data in the memory were:0x00000D50, 0x00000000, and 0x0000000.

 

Maybe the configuration for the SPORT with PCG not correct in the code, but I can't figure out where it is.

 

Would you please check it for me?

 

Attached is the code for your consideration.

 

Thanks a lot,

 

Ning

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