Gen 1.5 debug serial port (plus GPIO map)

John Watlington wad at laptop.org
Fri Apr 17 15:54:36 EDT 2009


On Apr 17, 2009, at 3:40 AM, Mitch Bradley wrote:

> John Watlington wrote:
>>
>> In my day job (OLPC support), I'm constantly reminded of the  
>> importance
>> of the serial port to repair centers.
>>
>> Here is the proposed plan of record:
>> 1) There will be a prominently located (i.e. at the edge of the  
>> board) jumper
>>    which indicates to OFW that it should set up the VX855 to  
>> provide a serial
>>    port, and not a video capture port.
>> 2) In order to use the serial port, a user should disconnect the  
>> camera
>>    by removing the ribbon cable from the connector.
>> 3) In production, both the jumper and the serial connector might  
>> be depopulated.
>>    In the process of soldering a serial connector on the board,  
>> the jumper can be shorted...
>
> I wonder if there is some location for the serial connector that  
> would not require removing the back panel.   Perhaps somewhere near  
> the backlight cable.  I'd like to eliminate the steps of removing  
> the 4 screws underneath the display, removing the rocker so it  
> doesn't fall out, carefully supporting the display while flipping  
> the back unit to a position where you can release the back panel,  
> then undoing that and replacing the 4 screws, then remembering to  
> replace the rocker.

Not without a tooling change, although it would be a
minor one.  But so far we aren't planning any...
I'm thinking about right above the rocker switch, where there
is currently an opening allowing the speaker wire to be snaked
through.

Allowing access to the camera connector is a larger problem.

Leaving the serial connector populated on production XOs was
"an oversight", and the plan is to remove it this time. The cost is
a few pennies, but they add up.


Cheers,
wad



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