DS2409P-TU0026R Ver la hoja de datos (PDF) - Maxim Integrated

Número de pieza

componentes Descripción

Fabricante

DS2409P-TU0026R

MicroLAN Coupler

Maxim Integrated 

DS2409

64-BIT LASERED ROM

Each DS2409 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 of the lasered ROM is generated using the polynomial X8 + X5 + X4 + 1.

Additional information about the Dallas Semiconductor 1-Wire Cyclic Redundancy Check is available in

the Book of DS19xx iButton Standards. The 64-bit ROM and ROM Function Control section allow the

DS2409 to operate as a 1-Wire device and follow the 1-Wire protocol detailed in the section “1-Wire Bus

System”. The functions required to exercise the control functions of the DS2409 are not accessible until

the ROM function protocol has been satisfied. This protocol is described in the ROM functions flow

chart (Figure 7). The 1-Wire bus master must first provide one of the five ROM function commands.

After a ROM function sequence has been successfully executed, the bus master may then provide any one

of the function commands specific to the DS2409 (Figure 5).

HIERARCHICAL STRUCTURE FOR 1-WIRE PROTOCOL Figure 2

64-BIT LASERED ROM Figure 3

MSB

8-Bit CRC Code

MSB

LSB

48-Bit Serial Number

8-Bit Family Code (1FH)

LSB MSB

LSB MSB

LSB

3 of 18

102199

Share Link: