DS2433

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scratchpad or there was a loss of power since data was last written to the scratchpad. The master does not

need to continue reading; it can start a new trial to write data to the scratchpad. Similarly, a set AA flag

together with a cleared PF flag indicates that the Write command was not recognized by the device. If

everything went correctly, both flags are cleared and the ending offset indicates the address of the last

byte written to the scratchpad. Now the master can continue reading and verifying every data byte.

After the master has verified the data, it has to send the Copy Scratchpad command. This command must

be followed exactly by the data of the three address registers TA1, TA2 and E/S. The master may obtain

the contents of these registers by reading the scratchpad or derive it from the target address and the

amount of data to be written. As soon as the DS2433 has received these bytes correctly, it will copy the

data to the requested location beginning at the target address.

HIERARCHCAL STRUCTURE FOR 1-WIRE PROTOCOL Figure 2

64-BIT LASERED ROM Figure 3

MSB

LSB

8-Bit CRC Code

48-Bit Serial Number

8-Bit Family Code (23h)

MSB

LSB

MSB

LSB

MSB

LSB

1-WIRE CRC GENERATOR Figure 4

INPUT