MFRC522 sleep mode

Using Arduino Sensors
1

I have acquired one of the RFID scanner modules from ebay, based on the MFRC522 chip. The vendor does not supply any technical information, but as a spec item, states that the unit uses < 80 microamps in sleep mode. I want to create a portable scanner with a long battery life, so I am interested in this sleep mode, but I can't find any reference anywhere as to how one induces sleep mode. Does anybody know how sleep mode is activated?

Thanks in advance for any help.

2

The MFRC522 has a pin called "NRSTPD" (Not Reset Standby Power Down)
When this pin is low the unit will go into sleep mode.
Make sure other pins eg SS are biased high (resistor to Vcc)

James