BBB MMC / SD detection instability with U-Boot 2014.04 (CPU 1GHz)

[Ian Lepore]

On Thu, 2014-05-22 at 11:34 -0300, Luiz Otavio O Souza wrote:
> Just picking one email to reply...
> 
> This is probably unrelated, but i can consistently corrupt my SD Card
> data if i connect (and use) a very small R/C servo (the 9g ones, used
> on foam planes) to the 3.3v on the expansion headers.
> 
> I'm not sure if it is because of noise or the power consumption, but
> looks like the BBB is really picky about the power conditions here.
> 
> Connecting the servo to the VDD_5V on the same header makes the problem go away.
> 
> So be careful about what you connect on your boards :)
> 

It looks like the 3v3b rail comes off a 500mA LDO and is already
powering several of the onboard chips (including eMMC and at least part
of the ethernet phy), so it may be power consumption.

-- Ian