Can I use 50 Ohm calibrated bidirectional pins on an Arria 10 - seems not?

Hi Yuan,

I have checked 4 different pins on a 10AX027H4F35E3SG device, plus 1 pin on the 10AS066 that's on the SoC dev board. All behave in the same way.

Some tests I've done:

• Pin = inout, GPIO IP = Bidirectional, Calibration = On, Result = No output
• Pin = inout, GPIO IP = Bidirectional, Calibration = Off, Result = OK

• Pin = inout, GPIO IP = Output with OE (variable), Calibration = On, Result = No output
• Pin = inout, GPIO IP = Output with OE (fixed to '1'), Calibration = On, Result = No output

• Pin = inout, Simple Verilog code with OE (Variable), Calibration = On, Result = No output
• Pin = inout, Simple Verilog code with OE (Variable), Calibration = Off, Result = OK

• Pin = output, GPIO IP = Output with OE (variable), Calibration = On, Result = OK

Resource Property Viewer shows the correct connections in all cases. It also shows Open Drain = Off.

The "Simple Verilog code with OE" was just this (showing just the appropriate lines of code):

inout m1_c1_dq10,

...

assign m1_c1_dq10 = counter[2] ? counter[0] : 1'bZ;

With the above, calibrated outputs fail, non-calibrated ones work. RPV shows the correct connections (with Open Drain=Off).

Regards,

Richard