DS2480B+T&R Maxim Integrated Products, DS2480B+T&R Datasheet - Page 11

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

Specifications of DS2480B+T&R

• 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: Lead free / RoHS Compliant

Search Accelerator Usage Example
Generate Reset Pulse
Set Data Mode
Search ROM command
Set Command Mode
Search Accelerator On
Set Data Mode
Send 16 bytes
Set Command Mode
Search Accelerator Off
Set Data Mode
Do Memory Function
Set Command Mode
Generate Reset Pulse
CONFIGURATION COMMANDS
The DS2480B is designed to be configurable for the varying requirements of its application. When the
device powers up and/or performs a master reset cycle, the hard-wired default configuration settings take
effect. These settings will work on a short 1-Wire bus and assume standard 1-Wire communication speed.
To change these default settings and to verify the current settings, the logic of the DS2480B supports
configuration commands. A summary of the available configuration parameters, their default settings at
standard and Overdrive speed and their applicability is shown in Table 3.
Parameters not related to the communication speed on the 1-Wire bus specify the duration of the 12V
programming pulse, the duration of the strong pullup to 5V, and the baud rate on the interface that
connects the DS2480B to the host. The remaining three parameters are used to modify the 1-Wire
communication waveforms if one selects “Flexible Speed” (see Communication Commands for speed
selection).
Flexible speed is implemented to improve the performance of large 1-Wire Networks. This is
accomplished by:
 limiting the slew rate on falling edges (e. g., at the beginning of time slots, to reduce ringing),
 extending the Write-1 low time (allows the current flow through the network to end slowly, to prevent
 delaying the time point when reading a bit from the 1-Wire bus (gives the network more time to
 adding extra recovery time between Write-0 time slots (allows more energy transfer through the
The latter two functions are controlled by a single parameter. Taking advantage of flexible speed requires
changing one or more of these parameters from their default values. Otherwise the waveforms will be
identical to those at standard speed.
Each configuration parameter is identified by its 3-bit parameter code and can be programmed for one of
a maximum eight different values using a 3-bit value code. A matrix of parameter codes and value codes
with the associated physical values in shown in Table 4.
voltage spikes from inductive kickback),
stabilize, to get a higher voltage margin) and
network, to replenish the parasite power supply of the devices on the bus).
Action Sequence
11 of 32
Host TX
data
C1
C1
E1
B1
E1
A1
E1
F0
E3
E3
E3
CD or ED
CD or ED
(response)
(nothing)
(nothing)
(nothing)
(nothing)
(nothing)
Host RX
(nothing)
(nothing)
(nothing)
(as sent)