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Anomaly with DE2-115 about SMA_CLKOUT voltage levels

Honored Contributor II

As DE2-115 User manual says, I would expect to see on SMA_CLKOUT (and so on J15 connector) different voltage levels as I switch the position of the jumper JP6. Instead, I could observe the same voltage levels for any position of that jumper: the square wave my FPGA produces is something like 0 - 2.2 V. 


Looking on the schematics, I can find that a voltage translator is interposed between SMA_CLKOUT FPGA pin and J15 connector. The reference on the output side of this traslator is VCC3P3, so it seems like voltage levels on SMA connector couldn't vary with setting the jumper. 


Since manual and schematics say different things, I ask: can I vary the voltage levels on the SMA output connector in any way? 


Thank you for any help you will give me. 



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