PN7150 Autonomous tag detection

[Electronics_Engineer]

Hi,

I want to use PN7150 in autonomous mode to detect a tag presence. This is a requirement because the Host needs to perform other tasks as well. Is it possible that PN7150 will check for tag presence and if the tag is detected then PN7150 will give IRQ signal to the host for notification of tag discovery. 

The datasheet says:  For contactless card functionality, the PN7150 can act autonomously if previously configured by the host in such a manner

What kind of autonomous mode this datasheet is talking about? is the what we need?

How to put PN7150 into autonomous tag detection?

Is there any example code available for Autonomous Operation?

Thanks 

[Kan_Li]

Hi @Electronics_Engineer ,

I think this feature is referring to the card emulation function, as shown below:

so this should not be what you are looking for. I think you are referring to the reader function, right?

While it is possible to put PN7150 into autonomous tag detection, that requires the host controller runs some kind of RTOS, for example, freertos, which may switch to other tasks when the application set up PN7150 into a discovery loop, and then PN7150 may notify the host via IRQ pin in case of card detection.

The latest NXP-NCI_MCUXpressoExample_V1.6 provides such kind of demo for K64, in which FreeRTOS is used. Please kindly refer to the following for details.

you may download this package from the following link:

https://www.nxp.com/docs/en/application-note/AN11990.pdf

https://www.nxp.com/webapp/Download?colCode=SW4325&appType=license&location=null

Hope that helps,

Have a great day,
Kan

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[Electronics_Engineer]

Thank you @Kan_Li for the response

Yes, you are right I'm looking for an Autonomous operation of PN7150 for read/write activity. In my application, there is no OS used and we are using bare-metal code for NFC tag detection. We want to achieve something similar as mentioned below:

-> Host configures PN7150 into autonomous discovery mode

-> PN7150 runs discovery autonomously and gives IRQ when tag-detected

-> Based on response Host will identify Tag technology and read NDF Message if required

-> PN7150 again starts Autonomous tag detection

-> The cycle goes one

Can we achieve something like this?

Thanks

[Kan_Li]

Hi @Electronics_Engineer ,

Yes, I think it is possible, but our bare metal demo just polls IRQ pin in a while loop, I am afraid you have no demo for reference unless you use RTOS in the implementation. 

Have a great day,
Kan

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[Electronics_Engineer]

Thank you @Kan_Li 

I have a question regarding the NFC Polling state machine. After successful tag detection, does PN7150 start to poll for NFC tag again or do we need to fire an NCI command to start discovery again??

Thanks

[Kan_Li · Accepted solution]

Hi @Electronics_Engineer ,

Actually it depends on the RF_DEACTIVATE_CMD issued to PN7150 in the end of RFST_POLL_ACTIVE state, it may return back to idle mode or start discovery again.

Please kindly refer to https://www.nxp.com/docs/en/user-guide/UM10936.pdf for more details.

Have a great day,
Kan

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