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How do I implement an external differential clock in VHDL for the CMOD S7? Vivado keeps on telling me to inset this flag in my constraint file: set_property CLOCK_DEDICATED_ROUTE FALSE However, I care about timing because it's an external clock signal. I'm using a clock dedicated route(Pmod pin are 2×6) as seen in this schematic.
Hi Folks Although the Analog Discovery has fully differential analog (scope) inputs, the Discovery BNC adapter board does NOT! For some reason the negative inputs of both analog channels have been connected to the Analog Discovery ground. Therefore, they form a short circuit between any conductors they are connected to. Why is this important? I just found out the hard way, when I connected the scope leads from the Discovery BNC adapter board to parts of a circuit at very different voltages. I was expecting each channel to measure the differential voltage across each probe. Instead, there was a crack, a flash, and a little jet of molten metal, as the clip on one of my scope probes vaporised! IMO this is a safety hazard, because adding the Discovery BNC adapter board to the Analog Discovery changes its electrical behaviour in a significant way (from differential to single ended) but there is no mention of this in the Discovery BNC adapter board reference manual. Users should be warned in BIG LETTERS about this change in behaviour, perhaps printed on the PCB as well. I was lucky, but providing users with a warning about this could save somebody's life one day. I can see that grounding the negative inputs could make sense, in that it makes the analog inputs behave more like a conventional oscilloscope, where the probe shields are usually returned to Earth. However, if you're going to do this you should at least warn users about what you've done. IMO it would be better to provide 4 sockets for scope probes, with each connected to one of the differential inputs, and all the scope shields returned to Analog Discovery ground. Then the Discovery BNC adapter board could be used for fully differential measurements. You could also provide jumpers to select single ended behaviour instead, by shorting the negative inputs to ground. At least that would give the user a choice about whether to operate as differential or single ended inputs.