Using a wifi dongle on an XO-1(.5) -- another dongle

[John Watlington]

On May 1, 2014, at 6:32 PM, James Cameron wrote:

> On Thu, May 01, 2014 at 03:56:32PM -0400, Nathan C. Riddle wrote:
>> Found another Ralink device that works: RT5370.   [...]
>> Now, is there a device based on Ralink chips to replace the internal
>> Libertas wireless module ? :)
> 
> No, certainly not.
> ...
> And, if I'm reading the schematics right, there's also two voltage
> variants, so the modules for XO-1.5 (3.3V) can't be swapped with the
> modules for XO-1.75 and XO-4 (1.8V).

Only cards built before we added the ESD protection (very early in
production) are limited to operation at +3.3V.   Most of the cards used
in XO-1.5 operate at either +3.3V or +1.8V, and are identical to the
88W8686 modules were used for XO-1.75 and XO-4.

> The XO-1.5, XO-1.75, and XO-4 main board wireless socket is a
> Mini-PCIe connector, but the electrical interface is custom, and
> carries SDIO, wireless indicator LED, and wakeup signals, so any
> new module must be custom made for the hardware.

The miniPCIe form factor is frequently used for USB-based wireless cards as
well, and XO laptops do provide USB signals at the appropriate pins although
the shipped wireless card doesn't use it.
Power, ground, and some auxiliary signals use standard pins.
But we did reuse the actual PCIe signal pins to provide the SD interface
so you might need to cut some wires to avoid conflict.
The pinout is available at:
http://wiki.laptop.org/images/d/d9/XO_4_Pinouts.pdf

Cheers,
wad