DS2432 데이터 시트보기 (PDF) - Maxim Integrated

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DS2432

1Kb Protected 1-Wire EEPROM with SHA-1 Engine

Maxim Integrated 

ABRIDGED DATA SHEET

DS2432

64-BIT LASERED ROM

Each DS2432 contains a unique ROM code that is 64 bits long. The first eight bits are a 1-Wire family

code. The next 48 bits are a unique serial number. The last eight bits are a CRC of the first 56 bits. (See

Figure 3.) The 1-Wire CRC is generated using a polynomial generator consisting of a shift register and

XOR gates as shown in Figure 4. The polynomial is X8 + X5 + X4 + 1. Additional information about the

1-Wire Cyclic Redundancy Check is available in Application Note 27. The shift register bits are

initialized to zero. Then starting with the least significant bit of the family code, one bit at a time is

shifted in. After the 8th bit of the family code has been entered, then the serial number is entered. After the

48th bit of the serial number has been entered, the shift register contains the CRC value. Shifting in the

eight bits of CRC should return the shift register to all zeros.

HIERARCHCAL STRUCTURE FOR 1-Wire PROTOCOL Figure 2

BUS

Master

1-Wire net

Other

Devices

Command

Level:

1-Wire ROM Function

Commands (see Figure 9)

DS2432

Available

Commands:

Read ROM

Match ROM

Search ROM

Skip ROM

Resume

Overdrive Skip

Overdrive Match

Data Field

Affected:

64-bit Reg. #, RC-Flag

64-bit Reg. #, RC-Flag

64-bit Reg. #, RC-Flag

RC-Flag

RC-Flag

RC-Flag, OD-Flag

64-bit Reg. #, RC-Flag, OD-Flag

DS2432-specific

Memory Function

Commands (see Figure 7)

For details see the full

version of the data sheet.

64-BIT LASERED ROM Figure 3

MSB

8-Bit CRC Code

48-Bit Serial Number

MSB

LSB MSB

LSB

8-Bit Family Code*

LSB MSB

LSB

*For the actual Family Code value, refer to the full version of the data sheet.

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