NTAG I2C Plus: NFC to I2C pass-through without MCU

[cory_a_lord]

Is it possible to use an NFC reader to read data from an I2C sensor, using an NTAG I2C Plus tag for bidirectional communication, without an MCU? Basically I'll be using the NFC antenna in an Android phone as the master, using the NTAG as a communication bridge.

[cory_a_lord]

Apologies, my reply may have been confusing. Let me rephrase my question:

What is the output voltage of the GPIO pins on the NTAG SmartSensor NHS3100 IC when it is NFC field powered?

[Kan_Li]

Hello Cory,

Referring to the data sheet, GPIO is powered by 1.6V.

So I think the output high voltage should be 1.6V as well.

Have a great day,
Kan

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[cory_a_lord]

Thanks for looking into that, Kan_Li. I saw that diagram in the datasheet. If that is accurate, it appears there Digital GPIO pins would be 1.2V

I ordered the eval board. When I find out the definitive answer I'll post it here.

[Kan_Li]

Ok, please kindly let me know if there is any issue.

Have a great day,
Kan

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[Kan_Li]

Actually it is  not possible to start the pass through mode without a MCU, how about the following product, which has NTAG and MCU in a single chip. You may use it to connect with multiple sensors.

NHS3100: NTAG SmartSensor with Temperature Sensor and Digital IOs | NXP 

Hope that helps,

Have a great day,
Kan

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[cory_a_lord]

Thanks for your swift reply, Kan_Li. I appreciate the clarification about the NTAG I2C Plus.

I was looking at the NTAG Smart Sensor ICs for my use case. "Energy Harvesting" works differently with those chips. When the NTAG Smart Sensor is being powered from an NFC field you can power external sensors using a GPIO pin pulled high instead of a dedicated "VOUT" pin, like the NTAG I2C Plus. I read that the GPIO voltage is 1.8V, which would be a problem for my sensor which needs at least 3V. Is there a way to get 3V out of an NTAG Smart Sensor chip when it is field-powered?