Re: Raduino Clone kit from W0EB-N5IB #ubitx


Gary Anderson
 

Hi Glenn,
As far as I know, and have used, the physical layer (e.g. hardware) is defined as an open drain / open collector.  I haven't seen the Ap note.  If you have a link you could share, I would like to review.
For bit banging with a standard digital I/O port.  You set the port as an input, set the drive state to 0.  You bit bang between input and output states.

For the case we have here, between a 3.3V and 5V device, the pull-up to 3.3V Si5351 meets/ exceeds the VIH of the 5V Nano, so all is good.
However, if you need to interface between say a 1.2V or 1.8V to a  5V  I/O you would need to level shift......  I see how this Ap note could be going now.

I will admit, that I read you post under a fog of too many folks are destroying Nanos. I'd rather have a discussion then a fellow ham wondering why something went wrong when it worked fine yesterday.

Cheers,
Gary

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