Is PN5180 VHDF output sufficient for K81 LLWU input?

[deniscollis]

I want to use the PN5180's Zero Power Wakeup feature to interrupt/wake-up the K8x.  The theory appears to be that energy from, say, a smart phone NFC is received by the PN5180's antenna and sent directly out the VDHF pin.

The question is whether the PN5180's VDHF output can be directly connected to the K8x's LLWU input, or if the VHDF output signal must first be conditioned by some device, like a comparator with push-pull output, to provide sufficient power to trip the LLWU?

For simplicity of design I would favor the direct option, if it works!

[deniscollis]

Thanks Mike. 

This is helpful info, but I just need to add:

There is just one VDHF output from the PN5180 for the CMP-INP(PSEL[2:0]).  I must therefore use the DAC to provide the reference voltage to CMP-INM(MSEL[2:0].

Do you know if there is any example code specifically for the Zero Power Wakeup on the  PN5180/K81 coupled devices?

--

Denis

[Hui_Ma]

Hi,

From PN5180 aspect, there doesn't need software to enable Zero Power Wakeup feature.

No configuration of registers is required to use this functionality.

The VDHF pin need connect  with 470nF capacitor to GND.

From K81 aspect, customer can refer MCUXpresso SDK [cmp] software example for K81 CMP module application.

Customer also can refer [power_manager] demo about K81 how to enter low power mode and how to wake up.

Wish it helps.

Have a great day,
Mike

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[deniscollis]

Ah, I see that the K8x has a comparator peripheral, so no additional external hardware may be required.  I guess the question then becomes:  Can the K8x's onboard comparator be used as a wakeup source? 

[Hui_Ma · Accepted solution]

Hi Denis,

Yes, K8x comparator module can work as a wakeup source.

Please check below comparator working status during each low power mode:

The CMP modules are also wakeup source of LLWU:

Thank you for the attention.

Have a great day,
Mike

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