Sending via NFC, after NFC Wake Up on SD132

[Jensen]

Hello there,

my goal is to wake up via NFC from POWER_OFF Mode (sd_power_system_off). Then right after the nfc wake up sending some information (e.g. UUID) via the NFC module.

There seems to be a bunch of complications.

1. The NFC wake up example doesn't apply to Softdevices (I'm, using SD132, SDK13). I'm not able to figure out how to use the NFC Wake up on a Softdevice.

2. The "NFC BSP Module" Documentation says "This module is applicable only if NFCT is used exclusively for wakeup. If NFCT is used for a different purpose, this module cannot be used.

So waking up from power_off and sending right afterwards isn't possible? Am I misunderstanding something? Is there another way? I haven't found one yet. Using NFC only for wake up without beeing able to send data is kinda useless.

I hope I just got it all wrong, answers are much appreciated.

Kind regards Jensen

[Jørgen Holmefjord]

Hi,

1. The softdevice should not restrict or block access to the NFCT peripheral. You should be able to use the BSP NFC module to configure NFC as wakeup source, like in the wake-on-nfc example. You just need to make sure you enter sleep mode by using the softdevice safe API call sd_power_system_off(), or that you disable the softdevice before setting NRF_POWER->SYSTEMOFF = 1.
2. If the BSP NFC module is enabled, you cannot use the NFCT peripheral for other purposes. This can easily be workaround by enabling the BSP NFC module only right before your application is preparing to enter sleep mode. You can also setup NFC as wakeup source by enabling the SENSE task directly: NRF_NFCT->TASKS_SENSE = 1; before entering system off mode. Note that wakup from system off mode will cause the chip to reset, and you will have to setup the NFC peripheral for transferring data in the start of main.

Best regards,

Jørgen

[Jensen]

Hello Jørgen, your proposal, using NRF_NFCT->TASKS_SENSE = 1; just before entering sleep mode, works like a charm.

Initilazing NFC after wake up and sending data as shown in the "record_text" example also workes pretty easy.

I upvoted and marked you answer as correct. Thank you very much for your quick answer and have a nice day.

regards, Jensen