User's Manual

Product Specification and User Manual RFID GEN3 System
CONFIDENTIAL
Page 16 of 34
Figure 2: RFID DESS System Block Diagram
The vehicle ECU powers the RFID Post from the positive switched battery connection
(KL15). Once powered, the RFID Post senses the RFID Key’s magnet using its internal
hall sensor. The hall sensor’s output is pulled low if a magnetic field is sensed, allowing
the vehicle engine to start. At the same time, the RFID Post’s microcontroller (µC)
activates the RFID initiator/reader, powering the RFID Key’s tag, allowing it to send it’s
UID. A message is then transmitted to the ECU through a bidirectional communication
link. Refer to section 3.4 for additional details about RFID tag reading sequence.