Cross-talk square-wave?

[Paul Koning]

> On Mar 29, 2017, at 1:25 PM, Paul Koning via cctalk <cctalk at classiccmp.org> wrote:
> 
> ...
> SD cards are not SPI, they are a variation of MMC. 

Sorry about that, it turns out I was working from obsolete memories.  That used to be true, isn't any longer. 

In any case, you're dealing with pretty fast signals, treating them as transmission lines is going to be important.

	paul