I did pull up RX. Finally after 3 days I found the problem, but still do not understand why it would not boot.


I chose the most expensive PCB manufacturer for the 6 prototypes - 4 layer board. They are capable of doing 64 layers. Well so they made a mistake with the photoplotting and shorted the following lines internally to the ground plane.









From: Ash Charles-2 [via Gumstix] [mailto:[hidden email]]
Sent: 30 Maart 2012 06:49 PM
To: glamprecht
Subject: Re: How to debug hardware problem?



If the console/RX line is floating, the OMAP boot ROM may think
something is trying to communicate. This line should be high


On Sun, Mar 25, 2012 at 12:03 PM, glamprecht <[hidden email]> wrote:

> I've designed some of my own expander boards and manufactured 6 of them. I
> have taken the Chestnut43 as basis. I also have a Chestnut43.
> On the Overo Fire after a second of power up, the middle led gives a flash
> and then about 2 seconds later the blue LED starts flashing. This indicates
> that it is booting up. If the reset is held in or it does not boot up the
> middle LED just stays on.
> If I plug in the Overo Fire on the Chestnut43 it boots up.
> If I plug in the Overo Fire onto any of my 6 boards, the middle LED just
> stays on. I presume it does not boot up. I have only populated the 3.3V
> power supply and nothing else. Am I correct in saying that if only power is
> applied to the 4 3.3V lines and the 4 GND lines it should start up? All the
> other signals can be floating?
> Back to the Chestnut43 all works.
> To eliminate my Power Supply which I think is perfect, I have desoldered my
> 3.3V regulator and cross wired the Chestnut 3.3V to my board with 1.5" 1.5mm
> square cable. I have some 10uF low esr caps close to the 70 pin connectors.
> Still does not work.
> I have tried adding a reset switch without any luck.
> Either my presumption that it should work with stock firmware if only 3.3V
> is applied is incorrect, or there is something not shown on the Chestnut43
> schematics or there is something wrong with my 70pin connectors.
> In any case is there any way that I can use a multimeter/oscilloscope or
> logic analyser connected to parts/pads on the OVERO itself to see if it is
> in Reset state or not. Whether it is power-good or not? I have no problem
> soldering wire wrap wire on 0402 or even smaller scale.
> Hope someone can help me. I am really stuck here.
> --
> View this message in context: click here.

View this message in context: RE: How to debug hardware problem?
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