>> For a project I am using a 16F685 and two HALL sensors as a indexing
>> and station sensor device.
>> I know that the TLE4905L device
>
> http://www.micropik.com/PDF/TLE4935L.pdf
>
>> has a logical output but would it be
>> necessary to include some debounce code in the routines.

> To debounce what ? What would be bouncing ?

Hall devices do not have bounce behaviour within the IC switch itself *BUT* 
there may still be mechanical variations in what is being sensed which drive 
the sensor backwards and forwards past its trigger point and effectively 
cause "bouncing". This could occur eg on a rotating disk if there is 
vibration present.

Generally magnetic sensors will exhibit a degree of inherent hysteresis due 
to the properties of the magnetic circuit, and will also often have inbuilt 
explicit hysteresis as well. As Jan-Erik notes, the IC cited apparently has 
this feature.

> Note that the HALL sensor has an internal ST stage before
> the output driver.

Accordingly, deboune would be required only in extremely mechanically noisy 
cases. Try it in a worst case situation, or analyse the field variations 
that you expect to be present, and see if debounce seems necessary.



            Russell 

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