[time-nuts] DS1620 Variants in the Thunderbolt

Hal Murray hmurray at megapathdsl.net
Sun Sep 26 05:31:26 UTC 2010

beale at bealecorner.com said:
> My understanding of the current DS1620 data sheet is that you can better
> than 0.5 C resolution, by reading some extra registers and doing a
> subtraction and a division, as mentioned below. Just wondering if this is
> something that could be accessible in a recent Thunderbolt, or is the
> firmware not modifiable, and the chip's 3-wire interface is not available
> externally? 

Dallas/Micron changed something between rev D and E.  I've never seen a 
description of that change.

As far as I know, the firmware in the TBolt's isn't hackable and I've never 
seen any comments about being able to do low level things like talk to the 
DS1620 using commands from the serial port.

So far, anybody who has been interested has just changed to an old rev of the 

These are my opinions, not necessarily my employer's.  I hate spam.

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