AnsweredAssumed Answered

i.mx6ull sd boot bus width

Question asked by David Luberger on Jul 13, 2018
Latest reply on Jul 13, 2018 by igorpadykov

I'm mostly following the EVK reference design, but I noticed in the boot config via gpio, the sd card boot setting is hard-wired for 1-bit bus width, yet off-the-shelf sd cards are 4-bit.  I read somewhere that during boot you *can* use 1-bit communication (i'm not sure why one would do that) but I don't see anywhere how the sd card peripheral then gets "put back" to 4-bit mode.  clearly the EVK works so it's happening somehow, but I'm not seeing where. Is this simply a matter of configuring in the device tree?  where and how is the boot sd card changed from 1-bit to 4-bit after boot?