Am 2015-06-10 um 22:49 schrieb Jonathan Cameron:
> On 09/06/15 17:03, Martin Kepplinger wrote:
>> hi
>>
>> Is the in_accel_thresh_rising_value (or falling) threshold value signed
>> or unsigned?
>>
>> In other words: Is a RISING event fired on an absolute growing value in
>> the positive range, and a FALLING event on an absolute growing value in
>> the negative acceleration range (< 0g)?
>>
>> Or is a RISING event fired on a signed rising value, no matter if the
>> threshold is positive or negative, and a FALLING event on a decreasing
>> signed value, also when the threshold is positive?
>>
>> thanks
>>
>> martin
>>
> Hi Martin,
>
> The two relevant abi elements are:
> in_accel_thresh_rising_value and
> in_accel_mag_rising_value
> Once you know the second one exists then you can probably work out the
> meaning of thresh ;)
>
> Thresh is the value, mag(nitude) is the absolute value, so if you get one
> that is thresh, then if the channel can go negative, negative values are
> definitely possible. On an accelerometer, you can get either implemented.
> mag_rising is typically to allow motion detection, thresh_rising might
> be used to detect a change of orientation (put bounds around each axis
> at a particular point in time.
>
> There are also roc (rate of change) type event detectors on some accelerometers.
>
> Hope that clear the mud up ;)
>
> Jonathan
>
Hi Jonathan,
Oh I overlooked, this is clear now. So
events/in_accel_x&y&z_mag_falling_en for example is
a classic freefall detection. Would an implementation here just use
in_accel_mag_falling_value ? I'm not yet sure how an iio_event_spec
would look like in that case. Freefall is what I could do in my driver.
But this was very helpful, thanks for your time!
martin
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
