[time-nuts] Strange temperature peak

[Alberto di Bene]

On 5/27/2011 10:58 PM, WarrenS wrote:
> The Tbolt uses a special method to get high resolution data from its
> temperature sensor by combining three things.
> The first is the sensor's standard data output which is used for the most
> significant bits. This gives about 1 deg resolution.
> 2nd an internal register is used for the middle bits which gives resolution
> of 0.009 deg
> and then the Tbolt's firmware averages the internal register data to get the
> LS bits, with resolution (not accuracy) below 0.001 deg.
On 5/28/2011 4:12 AM, Mark Sims wrote:
> The spikes are due to an artifact in the way the Tbolt firmware reads the
> temperature sensor chip.  It reads two registers and combine the values to
> get a high-res temp reading.  But if the firmware accesses the registers
> in-between the time that the temp sensor chip updates them it can produce
> a bogus value.  Typically this seems to happen on average of once every couple of hours.

Warren and Mark,

    thanks indeed. This explains everything, and also some other idiosyncrasies I had noticed in the
temperature graph display.
All clear now :-)

73  Alberto  I2PHD