Detailed Description

The MAX66040 combines 1024 bits of user EEPROM,

128 bits of user and control registers, a 64-bit UID, one

64-bit secret, a 512-bit SHA-1 engine, and a 13.56MHz

RF interface (ISO/IEC 14443 Type B, Parts 2-4) in a sin-

gle chip. The memory is organized as 19 blocks of 8

bytes each. Except for the secret, each block has a

user-readable write-cycle counter. Four adjacent user

EEPROM blocks form a memory page (pages 0 to 3).

Memory protection features include write protection

and EPROM emulation, which the user can set for each

individual memory page. Page 3 can also be read pro-

tected for enhanced authentication strength. The

MAX66040 is accessed through the ISO/IEC 14443-4

block transmission protocol, where requests and

responses are exchanged through I-blocks once a

device is in the ACTIVE state. The reader must support

a frame size of at least 26 bytes. The data rate can be

as high as 847.5kbps. The MAX66040 supports AFI

and CID. Functions not supported are chaining, frame-

waiting time extension, and power indication.

Applications of the MAX66040 include driver identifica-

tion (fleet application), access control, electronic cash

(e-cash), and asset tracking.

Overview

Figure 1 shows the relationships between the major

control and memory sections of the MAX66040. The

device has six main data components: 64-bit UID,

64-bit read/write buffer, four 256-bit pages of user

EEPROM, two 8-byte blocks of user and control regis-

ters, 64-bit secret’s memory, and a 512-bit SHA-1

engine. Figure 2 shows the hierarchical structure of the

ISO/IEC 14443 Type B-compliant access protocol. The

master must first apply network function commands to

put the MAX66040 into the ACTIVE state before the

memory and control functions become accessible. The

protocol required for these network function commands

is described in the

Network Function Commands sec-

tion. Once the MAX66040 is in the ACTIVE state, the

master can issue any one of the available memory and

control function commands. Upon completion of such a

command, the MAX66040 returns to the ACTIVE state

and the master can issue another memory and control

function command or deselect the device, which

returns it to the HALT state. The protocol for these

memory and control function commands is described in

the

Memory and Control Function Commands section.

All data is read and written least significant bit (LSb)

first, starting with the least significant byte (LSB).

Parasite Power

As a wireless device, the MAX66040 is not connected

to any power source. It gets the energy for operation

from the surrounding RF field, which needs to have a

minimum strength as specified in the

Electrical

Characteristics table.

RF

FRONT-

END

VOLTAGE

REGULATOR

INTERNALSUPPLY

MEMORY AND

FUNCTION

CONTROL

ISO 14443

FRAME

FORMATTING

AND

ERROR

DETECTION

READ/WRITE BUFFER

SECRET

UID

REGISTER

BLOCK

USER

EEPROM

SHA-1

ENGINE

DATA

MODULATION

Figure 1. Block Diagram

ISO/IEC 14443 Type B-Compliant

Secure Memory

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