2001 Oct 04 6
Philips Semiconductors Product specification
HITAG core module hardware HTCM400
7 FUNCTIONAL DESCRIPTION
7.1 System overview
The HITAG core module is a compact module used in read and write devices for the 125 kHz family.
With only a few external components (antenna coupling network, interface driver and voltage decoupling) you can use
the HTCM400 as the central part of a HITAG reader module (see Fig.3).
handbook, full pagewidth
MGW324
I/O
FUNCTIONS
HOST
SYSTEM
HTCM400
ANTENNA
HITAG 1
HITAG 2
POWER
SUPPLY
Fig.3 System overview.
7.1.1 TRANSPONDERS
The HTCM400 integrated into a read and write device can
communicate with Philips HITAG 1 and HITAG 2
transponders.
7.1.2 HOST SYSTEM
The connection to the host (e.g. microprocessor or PC) is
a serial interface on CMOS level for data transmissions
over shorter distances. You can connect an RS232 as well
as an RS422 interface device. If you use an additional pin
of the HTCM400 (pin TXDEN) as control pin, you can
realize an RS485 interface.
7.1.3 I/O FUNCTIONS
The I/O lines form the connection to potential keys and
LEDs; two lines are wired as inputs and two as outputs.
7.1.4 CONNECTING THE ANTENNA
Connect an antenna as shown in Fig.4
The resistor R1 has to be used if the antenna voltage is too
high (see Section 11.7). With the capacitor C the antenna
tuning is done. R2 has only to be used for antenna cable
lengths of more than 500 mm and is used for damping.
For more details concerning thedesign of HITAG proximity
antennas, see Section 11.
handbook, halfpage
MGW332
TX1
V
DD
TxD
RxD
CORE MODULE
HTCM400
RX
AGND
antenna
R2
R1
(optional)
L
C
Fig.4 Connecting the antenna.
