PCF7936AS/3851/C,1-CT NXP Semiconductors, PCF7936AS/3851/C,1-CT Datasheet - Page 7

• Manufacturer Part Number: PCF7936AS/3851/C,1-CT
• Description: pcf7936as series 32-bit 125 khz read / write security...
• Manufacturer: NXP Semiconductors

NXP Semiconductors
Security Transponder (HITAG2)
7 FUNCTIONAL DESCRIPTION SECURITY
The PCF7936AS does not require any additional power
supply. It derives its power supply by inductive coupling to
the LF Field, which is generated by the basestation.
Reading and writing to the transponder is provided by
amplitude modulation of the LF field.
The Contactless Interface generates the chip power supply,
clock and reset and features the modulator, and
demodulator. The system clock is derived from the LF field
generated by the basestation that typically operates with a
carrier frequency of 125 kHz.
The Control Logic incorporates the data acquisition logic to
enable communication with the transponder and the
memory access control logic. Access to the transponder
memory (EEPROM) depends on the device configuration
and the authentication state. The memory is split into
blocks and pages with independent access rights, as
configured by the user and partly predefined by design.
Device authentication may be performed in Password
mode or in Ciphered mode. In Password mode the
basestation and transponder in plain exchange a set of
passwords, while in Cipher mode a mutual authentication
based on a security algorithm is performed that employs a
Secret Key and a random number. The security algorithm is
determined by the on-chip Calculation Unit that in addition
supports ciphered communication and data exchange
between the basestation and the transponder.
The Cipher mode is ideally suited for vehicle immobilization
application.
Transponder operation and authentication is controlled by
commands send form the basestation, while in Read Only
mode data transmission commences after device reset and
a time-out condition.
2010 May 04
TRANSPONDER
7
7.1 Memory Organization, EEPROM
The device incorporates 256 bit of non-volatile memory
(EEPROM) that is organized as 8 pages with 32 bit per
page, referred to as Transponder Memory, TM. The
Transponder Memory, TM, is split into areas for
Transponder Configuration/Personalization, TCFG, and
User Memory, USER, see Figure 3.
The TM segment can be accessed only, after successful
device
configuration, device authorization is performed either in
Password mode or in Cipher mode. Subsequent memory
access is provided only in accordance with the memory
protection settings applied.
Any
Configuration, TCFG, respectively Page 1 to 3, become
effective after a device reset or initialization sequence only.
The organization of the Transponder Memory, TM,
depends on the authorization method selected (Password
or Cipher mode) by the corresponding configuration bit
(ENC) see Figure 4.
Figure 3. Memory Organization
changes
authorization.
Transponder Memory, TM
Page 0
Page 4
Page 3
Page 7
made
Depending
regarding
TCFG
USER
Product Specification
PCF7936AS
the
on
CONFIDENTIAL
the
Transponder
device