AN5322 impedance measurement

AKril.1 · ‎2021-06-01

Hi, i am trying to measure the matching impedance of the antenna.

I have the following questions:

What is the driver stage and how can i turn if off?
How can i ensure that register 0x28 is set to 0x0F?
How can i ensure that tr_am bit is set to 1?

Thank you in advance.

Ulysses HERNIOSUS · ‎2021-06-01

Hi AKril.1,

turning off the driver stage is achieved by setting register 28h lowest nibble to 0xf. Bit tr_am is located in register 03h. How you achieve this depends on what you have. If you have your own board / running purely embedded you will need to issue proper register write commands over I2C or SPI (e.g. st25r3916WriteRegister()).

The easiest way is to use ST25R3916-DISCO PC GUI which gives you direct click-access to all registers.

Best Regards, Ulysses

View solution in original post

Ulysses HERNIOSUS · ‎2021-06-01

Hi AKril.1,

turning off the driver stage is achieved by setting register 28h lowest nibble to 0xf. Bit tr_am is located in register 03h. How you achieve this depends on what you have. If you have your own board / running purely embedded you will need to issue proper register write commands over I2C or SPI (e.g. st25r3916WriteRegister()).

The easiest way is to use ST25R3916-DISCO PC GUI which gives you direct click-access to all registers.

Best Regards, Ulysses