ST25R3916B, ISO14443 and 15693 perfect, Card Emulation no Reaction.

[GJaeg.1]

Hello,

I start testing with the STEVAL-M25R16B Board and use this Time the self compiled Demo from ST 
to test it. All works find.

Then i made an own PCB with Reader IC  and Antenna on it and connect it to your MCU /Display Board.
The Board is connected to 3.3V, GND and the SPI / IRQ Lines. 

The Antenna on my PCB is very small, only 21x26mm. Inductance measured with Siglent VNA 770nH.
( 0.5mm Track Width, 0.3mm Distance, 3 Turns) 

The from your Tools calculated Values and my final Values after tuning differ..

My Result: L=270nH, Cemv 680pF, Cs 220pF, CTune 430pF, Rs 0.68R 

I tuned the Circuit using my VNA and get a Reading Distance of about 25mm for 14443 Keyfobs and Cards
and about 6cm for ISO15693 Card.

This all works fine.  Smith Chart looks perfect.
The Rx Voltage is about 1.5Vpp. The Voltage Divider Capacitors are 33p/120p.ST25R

Problem: Tags are working but in Emulate Mode i got no Reaction. With the Original Antenna (66x66mm) all is fine.
Need a little help how to go on...

 

[Travis Palmer]

Hello GJaeg.1,

 

The first step in card emulation of the ST25R products is to recognize the field of the initiator.

Can you please observe the efd_o bit while approaching with another reader?

Some more information about the efd:

External field detector
This is a low power block used in the active or passive target mode to detect the presence of
an external RF field. It supports two different external field detection thresholds, namely
Peer detection and Collision avoidance threshold.
The Peer detection threshold is used in the active and passive peer to peer modes to detect
when the peer device turns on its RF field.
The Collision avoidance threshold is used to detect the presence of an external RF field
during the RF collision avoidance procedure.

BR Travis