[Arm-netbook] GR8 based EOMA68 card

Luke Kenneth Casson Leighton lkcl at lkcl.net
Mon May 15 01:53:15 BST 2017

ismo you say the following in the document:

"Without a front panel USB-OTG port the compute module cannot be
powered as-is and thus is not EOMA68 compatible."

that's a misunderstanding.  there is absolutely nothing in the
standard which states "There Must Be A USB-OTG Port On The Front

there *is* however a section which states that the power must be *OTG-LIKE*.

in other words if you *HAVE* an OTG port you *MAY* wire that
*DIRECTLY* to the EOMA68 5V pins, as-is.  i.e. OTG VBUS *IS* EOMA68 5V

thus, if power is provided into the OTG port it can also go directly
out to the Housing.  exactly what happens after that is not your
problem (for example: in the case of the libre 15.6in laptop it
happens to be possible to charge the battery from it, but not enough
to actually run the laptop itself.  but, to reiterate: that is *not*
your concern as a Card designer).

if on the other hand you do *NOT* have an OTG port, then, obviously,
the EOMA68 5V power is just a plain 5V DC input.

given that there's only 2 USB ports on the GR8, dropping an OTG port
and a USB hub is what i'd recommend.  the only reason i put an OTG
port on the EOMA68-A20 is because the A20 actually has 3 USB ports (2
USB2, one OTG).


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