[Cryptech Tech] RTC on Alpha

[Joachim Strömbergson]

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Aloha!

Fredrik Thulin wrote:
> The suggestion has been made to remove the external RTC chip
> currently on the Alpha schematics, and instead just rely on the RTC
> inside the ARM.
> 
> OK to remove external chip? The internal RTC is likely easier to 
> interface with, so it saves us engineering time.

There were a few arguments for having a separate RTC:

- - Compartmentalization. Divide functionality onto parts that are easier
to test.

- - Precision. The Microchip MCP79412 provides 1 ppm resolution and is
very stable.

- - Power consumption. The external chip consumes 925 nA at 3.0 on
battery. What is the power consumption for the STM32 just running the
internal RTC?

- -- 
Med vänlig hälsning, Yours

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