How to reconfigure the NHS3100 startup state to take temperature measurements only under NFC field in battery-less application?

[stevewald]

We need to reconfigure the NHS3100 startup state to take temperature measurements only under NFC field for a battery-less application. I don't see where in the TLogger sources that the initial state is configured. Can someone provide some hints or clues?

[driesmoors · Accepted solution]

The current firmware (SDK 10.1) will already make a temperature measurement each time is tapped by the phone, regardless whether it is configured or not. This value is also passed along in the NFC shared memory as a text record. You can have a look at that when you use the phone without any APP being active.

Have a look at

• Init, file maintlogger.c, where TMeas_Measure is called.
• ResponseCb, file msghandler.c, where NDEFT2T_CreateTextRecord is called.

[stevewald]

Dries Moors had earned a badge for giving us more than this answer, including some source code to run a cleaner no-battery use case on the NHS3100. There are subtle problems with the initialization without a battery to maintain state. Thanks!

[IvanRuiz]

Hello,

It is only required to flash the NHS3100 with TLogger example. You will be able to take temperature measurements every time you approach your phone to the device. This is accomplished because of the phone's field power provided to the device even if NHS3100 is no longer battery powered.

Regards,

Ivan.