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DS2480 Datasheet, PDF (1/26 Pages) Dallas Semiconductor – Serial 1.Wire Line Driver | |||
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DS2480
DS2480
Serial 1âWireTM Line Driver
FEATURES
⢠Universal, commonâground serial port to 1âWireTM
line driver for MicroLANTM applications
⢠Works with all iButtons and MicroLANâcompatible
1âWire slave devices
⢠Communicates at regular and Overdrive 1âWire
speed and serial port data rates of 9600 (default),
19200, 57600 and 115200 bps
⢠Supports 12V EPROM programming and stiff 5V
pullâup for Crypto iButton, sensors and EEPROM
⢠Selfâcalibrating time base with ±5% tolerance for
serial and 1âWire communication
⢠Slew rate controlled 1âWire pullâdown and active
pullâup to accommodate long lines and reduce radi-
ation
⢠Userâselectable RXD/TXD polarity minimizes com-
ponent count when interfacing to 5V based RS232
systems or directly to UARTs
⢠Programmable 1âWire timing and driver characteris-
tics accommodate a wide range of MicroLAN configu-
rations at regular speed
⢠Smart protocol combines data and control information
without requiring extra pins
⢠Compatible to optical, IR and RF to RS232 converters
⢠Low cost 8âpin SOIC surface mount package
⢠Operates over 4.5V to 5.5V from â40°C to +85°C
DESCRIPTION
The DS2480 is a serial port to 1âWire interface chip that
supports standard and Overdrive speeds. It connects
directly to UARTs and 5V RS232 systems. Interfacing to
RS232C (± 12V levels) requires a passive clamping cir-
cuit and one 5V to ± 12V level translator. Internal timers
relieve the host of the burden of generating the timeâ
critical 1âWire communication waveforms. In contrast
to the DS9097(E) where a full character must be sent by
the host for each 1âWire time slot, the DS2480 can
translate each character into eight 1âWire time slots
thereby increasing the data throughput significantly. In
addition, the DS2480 can be set to communicate at four
different data rates including 115.2 kbps, 57.6 kbps and
19.2 kbps with 9.6 kbps being the powerâon default.
PIN ASSIGNMENT
GND
1âW
NC
VDD
1
8
RXD
2
7
TXD
3
6
POL
4
5
VPP
8âPIN SOIC
(150 MIL)
PIN DESCRIPTION
GND
Ground
1âW
1âWire Input/Output
NC
No Connection
VDD
4.5 to 5.5 Volts
VPP
Optional EPROM
Programming Voltage
POL
RXD/TXD Polarity Select
TXD
Serial Data from UART
RXD
Serial Data to UART
ORDERING INFORMATION
DS2480S
8âpin SOIC
Command codes received from the hostâs crystal con-
trolled UART serve as a reference to continuously cali-
brate the onâchip timing generator. The DS2480 uses a
unique protocol that merges data and control informa-
tion without requiring control pins. This approach main-
tains compatibility to offâtheâshelf serial to wireless
converters allowing easy realization of 1âWire media
jumpers. The various control functions of the DS2480
are optimized for MicroLAN 1âWire networks and sup-
port the special needs of all current 1âWire devices
including the Crypto iButton, EPROMâbased AddâOnly
Memories, EEPROM devices and 1âWire Thermome-
ters.
042498 1/26
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