DS1204V View Datasheet(PDF) - Dallas Semiconductor -> Maxim Integrated

Part Name

Description

Manufacturer

DS1204V

Electronic Key

Dallas Semiconductor -> Maxim Integrated 

DS1204V

BLOCK DIAGRAM - PROGRAM MODE Figure 4

D/Q

CLK

RST

CONTROL

LOGIC

COMMAND REGISTER

64–BIT

IDENTIFICATION

64–BIT

SECURITY MATCH

SEQUENCE - PROGRAM MODE Figure 5

PROTOCOL

IDENTIFICATION

COMMAND WORD

64 WRITE CYCLES

SECURITY MATCH

64 WRITE CYCLES

COMMAND WORD

Each data transfer for the normal and program mode

begins with a three-byte command word as shown in

Figure 7. As defined, the first byte of the command word

specifies whether the 128-bit nonvolatile memory will be

written into or read. If any one of the bits of the first byte

of the command word fails to meet the exact pattern of

read or write, the data transfer will be aborted.

The 8-bit pattern for read is 01100010. The pattern for

write is 10011101. The first two bits of the second byte of

the command word specify whether the data transfer to

follow is a program or normal cycle. The bit pattern for

program is 0 in bit 0 and 1 in bit 1. The program mode

can be selected only when the first byte of the command

word specifies a write. If the program mode is specified

and the first byte of the command word does not specify

a write, data transfer will be aborted. The bit pattern that

selects the normal mode of operation is 1 in bit 0 and 0 in

bit 1. The other two possible combinations for the first

two bits of byte 2 will cause data transfer to abort.

The remaining six bits of byte 2 and the first seven bits of

byte 3 form unique patterns that allow multiple keys to

reside on a common bus. As such, each respective

code pattern must be written exactly for a given device

or data transfer will abort. Dallas Semiconductor has

five patterns available as standard products per the

chart in Figure 7. Each pattern corresponds to a specific

part number. Under special contract with Dallas Semi-

conductor, the user can specify any bit pattern other

than those specified as unavailable. The bit pattern as

defined by the user must be written exactly or data

transfer will abort. The last bit of byte 3 of the command

word must be written to logic 1 or data transfer will abort.

NOTE:

Contact the Dallas Semiconductor sales office for a spe-

cial command word code assignment that makes possi-

ble an exclusive blank key.

021798 4/10

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