XO-1 SD card access during boot-up

John Watlington wad at laptop.org
Wed May 30 03:14:49 EDT 2012


On May 30, 2012, at 2:04 AM, James Cameron wrote:

> On Wed, May 30, 2012 at 12:08:40AM +0200, Sascha Silbe wrote:
>> Or is a "software reset" (i.e. CMD0) insufficient for
>> reinitialisation in Linux? (The standard suggests [2] it is, but actual
>> cards may or may not be behave that way.)
> 
> I don't know.  Let me know if you test it.  We know that a power cycle
> will reset a card.

Probably not.  If a card suffers a "brownout", which is what is happening here,
all bets are off.   You have to power cycle the card (leaving it powered off
long enough to ensure the supply voltage drops close to zero) to ensure proper
operation.

wad





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