Accelerometer (was: New prototype XO-1.75s in Auckland, New Zealand)

[Saadia Husain Baloch]

The difference in read rate is not the board (A3 vs B1) but a code change to
temporarily slow down the access of the TWSI bus the accelerometer is on due
to a temporary hardware constraint.
-Saadia

On Mon, Aug 29, 2011 at 12:10 PM, Bert Freudenberg <bert at freudenbergs.de>wrote:

>
> On 25.08.2011, at 07:47, James Cameron wrote:
>
> > On Thu, Aug 25, 2011 at 03:22:06PM +1000, forster at ozonline.com.au wrote:
> >>> I don't know enough about Turtle Blocks to comment, but if an
> >>> application such as Turtle Blocks tries to read the sensor, it will
> >>> probably block for as long as it takes for the transaction to complete
> >>> ... roughly 33 milliseconds.
> >>>
> >>
> >> I am getting 60mS per read in Turtle Blocks
> >
> > On an XO-1.73 A3, I saw 25 reads per second, which would have been 40mS
> > per read.
> >
> > On an XO-1.75 B1, I get between 17.07 and 18.22 reads per second in
> > /runin/runin-accelerometer with os40.  That would be 59mS to 55mS.
>
> A shell script needs 6.7 seconds to read it 100 times. That's 67 ms, B1 on
> os41.
>
> In any case it's fun to use, I made a little Etoys project to try:
>
>
> http://croquetweak.blogspot.com/2011/08/squeak-etoys-on-arm-based-xo-175.html
>
> (and in Etoys each read takes about 65 ms).
>
> - Bert -
>
>
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