Honored Contributor
Honored ContributorI see from your last post, that you apparently don't yet understand the difference between a logical signal viewn in Signal Tap and it's waveform shown by an oscilloscope. It may be helpful to read e. g. AN466 Cyclone III Design Guidelines to understand the issues of high speed digital signal interfaces.
Just some additional remarks. 1. A high drive strength FPGA output connected to an unterminated PCB trace will most likely show a waveform similar to your results. 2. With minimum drive strength, assuming a regular PCB design with sufficient ground connection, the waveform should be expected to show no or minimal overshoot. 3. When you connect an usual passive oscilloscope probe, you're effectively unable to see the real waveform, cause the probe impedance is distorting it considerably. The probes ground inductance does the rest. It's not completely impossible to capture realistic waveform with a passive probe, but requires some skill. An active probe or low impedance resistive divider would be required for an almost exact waveform display.
