Question regarding the activation of the NFCT peripheral

[Remo]

Hi

I'm using the NFCT peripheral of the nRF52832 Rev. 1.

The state machine (figure 118 in PS V1.4) shows that the NFCT can be activated by either issuing the TASKS_SENSE and the subsequent detection of a HF field, or by directly issuing the TASKS_ACTIVATE.

I'm a little bit confused when I'm allowed to trigger the TASKS_ACTIVATE. Due to the following statement from the PS, I assume that it should only be activated after the FIELDDETECTED event has occurred. Or is this statement only valid when the NFCT is in SENSE mode? Is it allowed to issue the ACTIVATE task when no external HF field is present?

The HFXO must be running before the NFC peripheral goes into ACTIVATED state. Note that the NFC
peripheral calibration is automatically done on ACTIVATE task. The HFXO can be turned off when the NFC
peripheral goes into SENSE mode. The shortcut FIELDDETECTED_ACTIVATE can be used when the
HFXO is already running while in SENSE mode.

Thank you very much in advance for the clarification!

Best regards.

[Simonr]

Hi Remo

You are allowed to trigger TASKS_ACTIVATE as long as the HFXO clock is running, seeing as this sets the NFC to its ACTIVATED state. Same goes for the FIELDDETECTED_ACTIVATE shortcut, as this activates the NFCT when a FIELDDETECTED event occurs. You can set the NFCT into ACTIVATED state without a previous FIELDDETECTED event manually, if you want to activate the NFCT for another reason.

Best regards,

Simon

[Remo]

Hi Simon

Thank you very much for the clarification.

Best regards