DS9097U
Universal 1-Wire COM Port Adapter
www.maxim-ic.com

FEATURES

PACKAGE OUTLINE§DB-09 version§§§§§§§§

True-Ground Interface to an RS232 COM Port for®
Reading and Writing 1-Wire Devices
Works with Bipolar as well as Unipolar LogicSignals
Compatible to COM port of (±)5V to (±)12V (DB-9
Version Only) or (±)6V to (±)12V (DB-25 Version)
Supports Reading and Writing at Regular andOverdrive Speeds
Provides Strong Pullup to 5V for Temperature-,
Crypto-, and EEPROM 1-Wire devices
Programs 1-Wire EPROM Devices (DB-25Version with External 12V Power Supply Only)
Communicates at Data Rates of 9.6 (default),
19.2, 57.6, and 115.2kbps
Standard DB-9 or DB-25 Female Connector and6-lead RJ-11 Connector for Easy Attachment ofStandard 1-Wire Cables and Probes
Includes DS2502 Identification Chip (DS9097U009 only)

RJ-11 pin 1

SIDE VIEW

REAR VIEW

DB-25 version
RJ-11 pin 1

2.1mm
power jack- contact+ contact
SIDE VIEW

REAR VIEWPIN ASSIGNMENTSCHEMATIC (for illustration)

DB-25: TXD (2), RXD (3), DTR (20), RTS (4), PCGround (7); all other pins not connected
DB-9: TXD (3), RXD (2), DTR (4), RTS (7),PC-Ground (5); all other pins not connected

DB-9 version
RS232
COM PortRTS
DTRRXDTXDGND

NOTES:* The external supply for the DS9097U-E25 must
provide well-regulated 12V @ 10mA minimum,
center = GND, outer ring = V+ (Newark Electronics
Stock No. 84F2081, Allied Electronics Stock No.
928-9895, Stancor Model STA-300R, or equivalent)

DS9097U-009
only5VReg.
4876ID
Chip

DS 52480B

2RJ-11654 1-W
3 GND
211

DB-25 version* The color of the DS9097U plastic case may vary.

Power JackRS232
COM Port

ORDERING INFORMATIONRTSDTRRXD
TXD
GND

DS9097U-009 DB-9, with DS2502 ID Chip
DS9097U-S09 DB-9, no ID chip
DS9097U-E25 DB-25, with EPROM Write

RJ-115VReg.

9V
4876DS 52480B

2654 1-W
3 GND
2111-Wire is a registered trademark of Dallas Semiconductor.

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DS9097UDESCRIPTION
The DS9097U is a sophisticated RS232 to 1-Wire adapter, which performs RS232 level conversion and activelygenerates the 1-Wire communication signals. Together with an adequate TMEX software driver, it enables an IBMcompatible PC to directly communicate with any 1-Wire device connected to the adapter's RJ-11 port. The DB-9
version reads and writes any non-EPROM 1-Wire device. To write to EPROM devices, the DB-25 version withexternal power supply is required.
All DS9097U adapters are based on the DS2480B Serial 1-Wire Line Driver chip and therefore are not a plug-in
replacement for the DS9097 or DS9097E. The RXD/TXD Polarity Select input of the DS2480B is tied to VDD (noninverting). Free software drivers can be downloaded from http://www.ibutton.com/software/tmex/index.html.
The DS9097U communicates with 1-Wire devices at regular speed as well as Overdrive speed. The serial port
must support a data transmission rate of 9600bps. Under software control, the adapter can be set up for RS232
data rates of 19200, 57600, and 115200bps. The two higher rates are recommended for communication at
Overdrive speed with Overdrive capable devices. Since the DS9097U operates in a byte mode, every data bytereceived from the RS232 port generates eight time slots on the 1-Wire line. At 19200bps data rate the DS9097UE25 is already faster than the DS9097 (E) at 115200bps.
Note that there are some COM ports that use signal levels of less than (±) 5V. The DB-9 versions of this adapter
will not work with such ports. The DS9097U-E25 adapter, however, will function in most cases if external power issupplied. Without EPROM programming, the external power may be anywhere in the range of 6V to 9V. For
EPROM programming the voltage must be at 12V in any case. Before using an externally powered DS9097U-E25
with a COM port of less than (±) 5V check whether the COM port will not be damaged by 5V on its RXD input.

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