Hi All!
Im trying to get my Altera FPGA to talk with a TI ads1278 ADC:
http://www.ti.com/lit/ds/symlink/ads1274.pdfThis is my first time trying this; and Ive only ever used my FPGA with a much simpler ADC. But Id like to get this fancy Delta/Sigma one up and running.
I put together what I thought would get the adc up and running, but all I got was my ADC getting really hot; and outputting a constant "0". So something is wrong. I have some very basic questions as this is my first ever time using this adc:
1. The ADC has lots of repeat pins; for example there are 5 analog gnds, 4 analog power supplys, 4 Digital Gnds, 4 Digital power supplys. Do all of these need to be connected? Or is connecting one sufficient?
2. What is the difference between Analog gnd and Digital Gnd? Is there any advantage in setting them differently?
3. There is an Analog power (4.7-5.25V); a Digital power supply (1.65-3.6V). But what about the following pins, do they need to be connected:
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VCOM AVDD/2 Unbuffered voltage output
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VREFN Analog input Negative reference input.
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VREFP Analog input Positive reference input.
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DVDD Digital power supply Digital core power supply
4. Overall, if you look at the timing plot on page 8 for the SPI interface; I am setting Drdy low every 512 clock cycles (using High Resolution mode, so Fsample/Fs=512). Is this correct?
5. I am using a housing which takes the ADC package and converts it to dip switches. Im using jumper cables to connect the dip switches on the ADC adapter to DIP pins, which Im using jumper cables to connect to the FPGA's pins. The adapter looks like this:
https://www.ebay.com/i/172825294343?chn=psAny possible issues with this adapter? My signals are running at a max of 25MHz through the cables conecting them; the cacbles are all under 6".
6. Is the sigma delta ADC supposed to get this hot? it smells like it may start melting; but I may have had it connected incorrectly.
Thanks, Id apreciate any guidance on this!