FIELD RISING and FIELD FALLING Interrupt flags are set simultaneously irrespective of direction of movement of reader with respect to st25dv tag

[ADant.1]

Hello,

I am working on project where I need to check if field is falling or rising. I have enabled the filed change interrupt in GPO, which works fine to generate the GPO interrupt. Unfortunately both the interrupt flags for field change interrupt i.e. field falling and field rising interrupt flags are set irrespective of whether reader is moved towards the tag or away from the tag.

Is this the general case that both the flags are set on field change interrupt?

If not then is there any setting which can be used to control the flag being set?

Any help would be much appreciated!

[ADant.1]

Update: Even wobble during the movement causing both flags to set. Is there a way to change the maximum required change in field to causes the interrupt to be triggered?

[JL. Lebon · Accepted solution]

Hello,

The field detection interrupt is directly tied to the presence of an RF field strong enough to power the RF part of the tag.

As soon as there is enough RF field strength to power the tag, the Field rising interrupt is triggered. As soon as the RF field is too low to powered the tag, the field falling interrupt is triggered.

There is no way to adjust the field level.

Best regards.