AN1949 STMicroelectronics, AN1949 Datasheet - Page 4

• Manufacturer Part Number: AN1949
• Description: RFID Reader using STMicroelectronics PSD MCU and CRX14 Coupler to Implement a China National ID Card Reader
• Manufacturer: STMicroelectronics

AN1949 - APPLICATION NOTE
Main Control Board
The main control board contains a uPSD3234A Control Unit, a security module and a power module.
Boosted Antenna Board
The range of the CRX14, to the tags, can be increased if the transmitted power is increased, and the re-
ceive signal is amplified. The boosted antenna circuit block diagram is shown in
Figure 2. Boosted Antenna Block Diagram
CRX14
CRX14 is a short range contactless coupler chip, compliant with the ISO14443 type B proximity standard.
It generates a 13.56MHz signal modulated according to ISO14443 type B proximity standard. The CRX14
features the ST anti-collision mechanism, which allows the reader to detect and identify all the tags that
are present in the operating range, and to access them individually. Because the CRX14 implements the
France Telecom-proprietary anti-clone function, the reader can also perform authentication of tags that
are equipped with the France Telecom anti-clone capability.
The CRX14 coupler interfaces between:
Operating from a 5V power supply, and delivered in a SO16N package, the CRX14 coupler chip is an ex-
cellent solution for building contactless readers, embedded in the final equipment, and offering a good
compromise between operating range and cost.
4/22
The uPSD3234A communicates with the PC using a USB/RS232 interface, and controls the card-
reader chip’s operation via the I
responsible for controlling and communicating with the security module.
The security module on this demonstration is reserved for future expansion. If the security
authentication mechanism is to be used, users can just simply put their security module into the
reserved space on the board, and program their own firmware. The basic operation to the security
module is fully compatible with ISO7816 (see the ISO7816 standard and the specific security module
datasheet). The clock of the security module can be provided either from the uPSD3234A’s PWM pin,
or directly from an external crystal oscillator. For details, see
The power module provides a stable 5V DC voltage supply to the system. The user should provide
the system with a 9 to 12V DC voltage through the power connector. In this demonstration, for
compatiblity with the µPSD33xx family, a 3.3V DC voltage is also provided.
the memory tags, on one side, through input/output buffers and the ISO14443 type B radio frequency
protocol, and
the system master processor, on the other side, through a 400kHz I
I 2 C Bus
CRX14
2
C bus. If the security module is used, the uPSD3234A is also
Filter and
Amplifier
Amplifier
Class E
Power
Matching
Circuit
Figure
2
10..
C bus.
Tags
Figure
2..
AI09744