DS2480B Maxim Integrated Products, DS2480B Datasheet - Page 10

• Manufacturer Part Number: DS2480B
• Description: IC LINE DRVR W/SENSOR 1-W 8-SOIC
• Manufacturer: Maxim Integrated Products
• Type: Line Driver, Transmitterr

Specifications of DS2480B

• Number Of Drivers/receivers: 1/0
• Protocol: RS232
• Voltage - Supply: 4.5 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

The type of time slot b2 (write 1 or write 0) is determined by the DS2480B as follows:
b2
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
et cetera
16
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.
To perform a Search ROM sequence one starts with all bits r
subsequent response bits r’
1, an error has occurred during the search procedure and the last sequence has to be repeated. Otherwise
r’
For the next Search ROM sequence one reuses the previous set r
being the index number of the highest discrepancy flag (that is, 1) and sets all r
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.
7
r’
7
r’
n
th
3
63
(n = 0 ... 63) is the ROM code of the device that has been found and addressed.
byte
= r
= b
= 1 if error (there is no response)
6
d
6
d
3
63
n
0
if conflict (as chosen by the host)
if no conflict (there is no alternative)
5
r’
5
r’
2
62
4
d
4
d
2
62
n
are 1s until the Search Accelerator is deactivated. Thus, if r’
3
r’
3
r’
1
61
2
d
2
d
1
61
1
r’
1
r’
0
60
10 of 31
0
d
0
d
0
60
n
n
(n = 0 ... 63) but sets r
being 0s. In case of a bus error, all
i
to 0 with i > m. This
63
m
and d
to 1 with “m”
63
are both