The processing logic implements the communication protocol. It also is
used to modulate/demodulate signals and to encode/decode digital bits during
the communication between the interrogator and the tag. The memory on
the IC may be divided in different blocks, called banks. A block may be a
read-only type, a write-one-time-only type, or a write-many-times type. Tags
use electrically erasable, programmable, read-only memory (EEPROM). This
type of memory does not require continuous power to store data. Therefore,
data stored on the tag is retained for a long period (several years), even though
no power may be available to the tag during this period. The type of data
stored in the memory depends on the protocol used. The IC may store tag ID,
object identifier, password, and error detection code such as cyclic redundancy
check (CRC).
CHAPTER 3 Tag Knowledge 63
FIGURE 3.1 RFID tag components and interconnection
Substrate