i'm debugging why microsd express card (pcie) doesn't link in latest 2 reform next board revisions. refclk on the slot pins looked like this: not good, big emi spike frequency disturbing it... (the clock signal is the yellow "sausage" in the middle, 100mhz. at least it tries to be)
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i then noticed that this EMI signal is still there on the scope when the board is turned off and all cables removed!
i turned of my pc and all kinds of lamps and stuff until i noticed it's this RSHTECH powered usb hub from amazon :0
with this device removed from my table, the refclk pin on my board suddenly looks pretty clean!
