[Cryptech Tech] Novena dev-bridge board status

[Joachim Strömbergson]

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Aloha!

Great work with this and the noise boards.

JoachimS

Fredrik Thulin wrote:
> On Wednesday, July 08, 2015 11:00:30 PM Jacob wrote: ...
>>> Real status will be reported here once I've put more (most?) of
>>> the components on the board. For now, I just put on the bare
>>> minimum of components plus some LEDs. I still haven't tried the
>>> real power circuitry for example.
>> It's still exciting to watch as you go through the verification
>> steps.
> 
> Ok, this far I have one dev-bridge board with all components
> mounted.
> 
> USART seems to work at 921600 bps (the ARM can read me the alphabet).
> Will verify communication is error-free next.
> 
> I'm measuring ~85 mA power consumption when powering the board
> through the USB_PWR connector. This is while busy-wait looping the
> ARM at 180 MHz.
> 
> The 5V rail is not exactly 5V any more. The schottky diode D2 and the
> inductor L2 (I put my finger up in the air and mounted a 47 uH there)
> causes a voltage drop of 0.8 volts. The noisy diode still gets 10.6
> volts which seems to be enough. There are numerous ways to improve
> the safety margin for future revisions.
> 
> The panic button of all things is the only thing that doesn't seem to
> be working this far =), although I haven't tested the RTC or tamper
> circuitry beyond mounting the parts. Either I misread the datasheet,
> the component footprint didn't lend itself to hand soldering, or I
> need to get the ATtiny up and running before I can really tell.
> 
> /Fredrik
> 
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- -- 
Med vänlig hälsning, Yours

Joachim Strömbergson - Alltid i harmonisk svängning.
========================================================================
 Joachim Strömbergson          Secworks AB          joachim at secworks.se
========================================================================
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