How do I implement Antenna measurement and tuning for a custom antenna board

[jkullds]

We have a custom antenna and reader board setup that uses the ST25R3916 reader chip and I would like to know how to implement the Discovery GUI "Tune Antenna" and "Measure Antenna" commands in my Test Application FW. Specifically, what functions need to be called before and after the st25r3916AatTune() API? I would like to be able to get the tuning results, e.g., AAT A/B, Amplitude, and Phase values.

Calling st25r3916AatTune() API by itself doesn't seem to work, e.g., amplitude and phase values returned are zero. I think I'm missing a bunch of steps in order to get this to work correctly.

Unfortunately, the HW setup can't be hooked up to the Discovery GUI PC app, hence, the question.

Thanks.

@tmuhlbauer@device-solutions.com

[jkullds]

With regards to the amplitude and phase values, I see that these values are returned after the call to 

aatMeasure() in st25r3916_aat.c. The amplitude and phase values are returned as integers while the Discovery GUI returns the values as decimal numbers.

How do we map the amplitude and phase integer values to the Discovery GUI decimal values? What equation do we use?

[Ulysses HERNIOSUS · Accepted solution]

Hi Jkullds, 

did you already study AN5322: Automatic antenna tuning (AAT) for ST25R3916/16B and ST25R3920/20B devices?

Please also see the section "Measure amplitude" and "Measure phase" in the DS for conversions.

BR, Ulysses