DS1204V Просмотр технического описания (PDF) - Dallas Semiconductor -> Maxim Integrated

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DS1204V

Electronic Key

Dallas Semiconductor -> Maxim Integrated 

DS1204V

DS1204V

Electronic Key

FEATURES

• Cannot be deciphered by reverse engineering

• Partitioned memory thwarts pirating

• User-insertable packaging allows personal posses-

sion

• Exclusive blank keys on request

• Appropriate identification can be made with a 64-bit

reprogrammable memory

• Unreadable 64-bit security match code virtually pre-

vents deciphering by exhaustive search with over

1019 possibilities

• 128 bits of secure read/write memory create addition-

al barriers by permitting data changes as often as

needed

• Rapid erasure of identification security match code

and secure read/write memory can occur if tampering

is detected

• Low-power CMOS circuitry

• Four million bps data rate

• Durable and rugged

• Applications include software authorization, gray

market software protection, proprietary data, financial

transactions, secure personnel areas, and system ac-

cess control

DESCRIPTION

The DS1204V Electronic Key is a miniature security

system that stores 64 bits of user-definable identifica-

tion code and a 64-bit security match code that protects

128 bits of read/write nonvolatile memory. The 64-bit

identification code and the security match code are pro-

grammed into the key via a special program mode oper-

ation. After programming, the key follows a procedure

with a serial format to retrieve or update data. Interface

cost to a microprocessor is minimized by on-chip circuit-

ry that permits data transfer with only three signals:

Clock (CLK), Reset (RST), and Data Input/Output (DQ).

PIN ASSIGNMENT

DALLAS

DS1204V

ELECTRONIC KEY

SIDE

1

5

BOTTOM: PIN VIEW

1.0 IN

See Mech. Drawings

Section

PIN DESCRIPTION

Pin 1 - VCC

Pin 2 - RST

Pin 3 - DQ

Pin 4 - CLK

Pin 5 - GND

+5 Volts

Reset

Data Input/Output

Clock

Ground

Low pin count and a guided entry for mating receptacle

overcome mechanical problems normally encountered

with conventional integrated circuit packaging, making

the device transportable and user-insertable.

OPERATION – NORMAL MODE

The Electronic Key has two modes of operation: normal

and program. The block diagram (see Figure 1) illus-

trates the main elements of the key when used in the

normal mode. To initiate data transfer with the key, RST

is taken high and 24 bits are loaded into the command

021798 1/10

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