DS2480B Maxim Integrated Products, DS2480B Datasheet - Page 6

• 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

In addition to the command codes explained in the subsequent sections the DS2480B understands the
following reserved command codes:
Except for these reserved commands, the Search Accelerator control and the first byte after power-on
reset or master reset cycle, every legal command byte generates a response byte. The pulse termination
code triggers the response byte of the terminated pulse command. Illegal command bytes do not generate
a command response byte.
COMMUNICATION COMMANDS
The DS2480B supports four communication function commands: Reset, Single Bit, Pulse, and Search
Accelerator control. Details on the assignment of each bit of the command codes are shown in Table 1.
The corresponding command response bytes are detailed in Table 2. The Reset, Search Accelerator
Control and Single Bit commands include bits to select the 1-Wire communication speed (regular,
flexible regular, Overdrive). Even if a command does not generate activity on the 1-Wire bus, these bits
are latched inside the device and will take effect immediately.
Reset
The Reset command must be used to begin all 1-Wire communication. The speed selection included in
the command code immediately takes effect. The response byte includes a code for the reaction on the
1-Wire bus (bits 0 and 1) and a code for the chip revision (bits 2 to 4).
Single Bit
The Single Bit command is used to generate a single time slot on the 1-Wire bus at the speed indicated by
bits 2 and 3. The type of the time slot (Write-0 or Write-1) is determined by the logic value of bit 4. A
Read Data time slot is identical to the Write-1 time slot. Bits 0 and 1 of the response byte transmitted by
the DS2480B at the end of the time slot reveal the value found on the 1-Wire bus when reading.
For a time slot without a subsequent strong pullup, bit 1 of the command must be set to 0. For a time slot
immediately followed by a strong pullup bit 1 must be set to 1. As soon as the strong pullup is over, the
device will send a second response byte, code EFh (read 1) or ECh (read 0), depending on the value
found on the 1-Wire bus when reading. The strong pullup directly following the single bit is used in
conjunction with the crypto iButton.
E1h
E3h
F1h
switch to Data Mode
switch to Command Mode
pulse termination
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