DS2480B

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101999

The type of time slot b2 (write 1 or write 0) is determined by the DS2480B as follows:

b2

= 1 if error (there is no response)

The response the host will receive during a complete pass through a Search ROM function using the

Search Accelerator consists of 16 bytes as follows:

first byte

7

6

5

4

3

2

1

0

et cetera

16

7

6

5

4

3

2

1

0

As before, the index (values from 0 to 63, “n”) designates the position of the bit in the ROM ID of a

MicroLAN compatible device. The character “d” marks the discrepancy flag in that particular bit

position. The discrepancy flag will be 1 if there is a conflict, or no response in that particular bit position,

and 0 otherwise. The character “r” marks the actually chosen path at that particular bit position. The

chosen path is identical to b2 for the particular bit position of the ROM ID.

1, an error has occurred during the search procedure and the last sequence has to be repeated. Otherwise

process is repeated until the highest discrepancy occurs in the same bit position for two consecutive

passes.

The table below shows an example for the communication between host and DS2480B to perform one

pass through the Search ROM function using the Search Accelerator. After a device has been identified

and addressed, a memory function (not specified here) is executed and finally a reset pulse is generated.

This example assumes that the DS2480B was in Command Mode and that regular 1–Wire speed is used.