Cycloneiii Flip Flop mistery

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First what is your clk speed?

second, do you do physical loop back or just inside fpga. How do you read back Tx pin (is it bidirectional)?

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Im using a 50 MHz clock.

Those pins are PIN_E18 and PIN_H17, Rx Input and Tx output respectively, in the EP3C25F324C6. Those are not biderectional.