How can I test reading performance of ST25R3918?

[HMura.8]

Hallo all,

I want to check the reading performance of ST25R3918 with our original antenna.

On your site, we can use ST25R3916DISCO for testing ST253918, but outpur power is different.

How can I test the performance of ST25R3918 with ST253916DISCO?

Do I need to replace IC chips?​

Please tell me the ditails of the evaluation method.​

​

Best Regards,

Hiromi Murayama

[Carlo Corlattoni]

Hello,

you can use the St25R3916Disco for testing, but you would need to set bit d_res<3:0> in TX driver register to 2 in order to emulate the ST25R3918 driver capability. Furthermore, you need to ensure not to exceed a maximum driver current of 85mA in case the internal LDO is used, or 125mA in case the drivers are supplied directly by VDD. Typically, the matching impedance for driving 85mA of current is around 40Ohm+j0, whereas for 125mA its about 24Ohm.

Also, ensure the varicaps are removed or not connected, because the ST25R3918 does not provide AAT pins.

Best regards,

Carlo

[HMura.8]

Hi Carlo,

Thank you for your reply.

I tride to buy ST25R3916Disco, but there was no distributor that had it in stock.

Is there any other way I can evaluate the read performance of the ST25R3918?

Best Regards,

Hiromi Murayama

[Brian TIDAL]

Hello,

you will find distributors on https://www.st.com/en/evaluation-tools/st25r3916-disco.html#sample-buy:

 

Rgds

BT

[HMura.8]

Hi Brian,

Thanks for your reply.

I checked RS COMPONENTS site on the all country in EUROPE , but all say "we can't find results" or 

"Permanently discontinued"

​

Can I use "X-NUCLEO-NFC06A1" for the same purpose as �?ST25R3916Disco�?？

​

Best Regards,

Hiromi Murayama​

[Ulysses HERNIOSUS]

Hello Hiromi,

the same is possible also on X-NUCLEO-NFC06A1, just there you need to change firmware on the NUCLEO STM32 board to apply the register settings.

When going through your ST Sales support you could also request an already adapted ST25R3918-DISCO board.

Best Regards, Ulysses

[HMura.8]

Hi All,

Thank you for your kindly help.

I have ​procured ST25R3916-DISCO finally :)

I tried to change  TX driver register to 2.

I set d‗res in register 28h as follows, but after running Polling, it reverts to the initial state.

Do I need to save the register values I changed? How do I save it?

​

[Ulysses HERNIOSUS]

Hi Hiromi,

the register map is more of a visualization and playground for the registers. Configuration is done by means of the analog config also available as a tab in the GUI. Also the DPO will be playing a role here. Looking at especially d_res I see the following (potentially competing) mechanisms:

1. Analog Config: Inside its CHIP_INIT mode it will set the d_res to 0x00
2. DPO: By default the board is set to perform Dynamic Power Adjustment: It measures the amplitude on RFI and sets the d_res to reduce power when a tag is in close proximity and to increase when further away.

So for playing with d_res I recommend to go to DPO tab and to disable it, and then on Analog Config tab set the value inside the CHIP_INIT mode and "Write to board".

Please be aware that in standalone/on-board GUI mode I assume it will switch back to DPO enabled and your settings likely are not used any longer. So better to evaluate based on PC GUI. If needed you could in a second step recompile the firmware with disabled DPO and change d_res default.

BR, Ulysses

[HMura.8]

Hi Ulysses,​

Thank you for your answer!

The problem has been solved!!!

​Sincerely thank!

Hiromi Murayama

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