Introduction - RFID: Fundamentals and Applications in Contactless Smart Cards and Identification - page 6

applications (Rankl and Effing, 1996). One example of this is the national insurance
card used by the state pension system in Germany (Lemme, 1993).

1.1.4.2 Microprocessor cards

As the name suggests, microprocessor cards contain a microprocessor, which is con-
nected to a segmented memory (ROM, RAM and EEPROM segments).
The mask programmed ROM incorporates an operating system (higher programme
code) for the microprocessor and is inserted during chip manufacture. The contents of
the ROM are determined during manufacturing, are identical for all microchips from
the same production batch, and cannot be overwritten.
The chip's EEPROM contains application data and application-related programme
code. Reading from or writing to this memory area is controlled by the operating
system.
The RAM is the microprocessor's temporary working memory. Data stored in the
RAM are lost when the supply voltage is disconnected (Figure 1.6).
Microprocessor cards are very flexible. In modern smart card systems it is also
possible to integrate different applications in a single card (multi-application). The
application-specific parts of the programme are not loaded into the EEPROM until
after manufacture and can be initiated via the operating system.
Microprocessor cards are primarily used in security sensitive applications. Examples
are smart cards for GSM mobile phones and the new EC (electronic cash) cards. The
option of programming the microprocessor cards also facilitates rapid adaptation to
new applications (Rankl and Effing, 1996).

1.1.5 RFID systems

RFID systems are closely related to the smart cards described above. Like smart card
systems, data is stored on an electronic data-carrying device — the transponder. How-
ever, unlike the smart card, the power supply to the data-carrying device and the
data exchange between the data-carrying device and the reader are achieved with-
out the use of galvanic contacts, using instead magnetic or electromagnetic fields. The

ROM
(operating
system)

CPU

Vcc GND

RST Vpp

EEPROM
(application
data)

RAM

CLK I/O

Figure 1.6 Typical architecture of a microprocessor card