Digilent Digital Discovery: HIGH Z for DIO 0 to 23 available?

[DigilentFan]

The pull resistors are selectable (0/Z/1) for DIO 34 to 39.

For DIO 0 to 23 the only Option available is (up/MIDDLE/down).

For some application a HIGH impedance (not MIDDLE but Z) would be useful, for sniffing signals for e.g..

Is there a hidden option/workaround to get high Z working also for DIO 0 to 23?

Thanks in advance for every hint!

 

[attila]

Hi @DigilentFan

There is no such hardware option, see VREFIO:
https://digilent.com/reference/test-and-measurement/digital-discovery/reference-manual#input_dividers

The DIN should be highly sensitive with the Middle option and adjusting the Digital Voltage/Threshold if needed.

[DigilentFan]

Thanks for your quick response!

If a high impedance is a must (for e.g. with weak pulls) only DIOs DIO 34 to 39 work (not surprisingly) as desired. For DIO 1-23 results are not as good since the pulls in the Discovery conflict with the bus pulls... The restriction is given by design. since D³ always pulls at DIO 1-23, even if not desired.