Multiple pulses are generated on GPO pin for ST25DV64KC micro, when NFC enabled mobile is kept near the antenna, it is expected to have only two pulses for RF activity entry and RF activity exit conditions

[SSBH]

Hi,

I am using ST25DV64KC micro for NFC communication interfaced with SAML micro controller. I have kept the setting for GPO signal as I should two pulses for every RF read/write session, first one indicating RF field is active and another one indicating RF field has been disabled. But , sometimes I am getting 4 pulses for successful RF read/write.

Could you please guide, which setting may cause this issue?

Another issue is, when I keep the NFC enabled mobile on antenna, I am continuously getting pulses on GPO pin, here I am expecting only one pulse indicating RF field is active as mobile is kept on antenna, and another pulse should appear on GPO pin when mobile is moved out of antenna range.

Can you tell me why this issue may appear?

Is there any setting or hardware precaution required to get only two pulses of GPO signal as per expectation for RF active and inactive status.

GPO1 & GPO2 settings are set as default and the values are as follows:

GPO1 = 0x11

GPO2 = 0x0C

Please let me know your inputs.

Thanks and Regards,

SSBH

[AJAY S]

You can Set GPO as High and Low when RF feild is available.

By using GPO_EN