The DS9097 COM port adapter is a simple, low-cost passive adapter which performs RS-232C (±12V) level conversion, allowing an iButton® probe to be connected to the serial port of a computer so that a non-EPROM iButton can be read and written directly. It can also read all EPROM-based iButtons. The serial port must support a data transmission rate of 115.2kbps in order to create the 1-Wire® time slots correctly. Nearly all PCs support the required data rate and are fully compatible with the DS9097. Since an 8-bit character (6 data bits plus start and stop bit) on the RS-232 port operating at 115.2kbps is used to form a single 1-Wire time slot, the maximum effective 1-Wire transfer rate is 14.4kbps (regular speed). Details on the operation of the DS9097 including software examples are found in application note 74, Section V.
The DS9097E is an upgraded version of the DS9097 that is capable of supplying the 12 volts necessary to program the EPROM-based iButton products (DS198x Add-Only iButtons) in addition to reading and writing SRAM and EEPROM-based devices (DS199x, DS196x, DS197x). When combined with the appropriate software, the DS9097E can be used in a standalone mode where all of the programming current is supplied by the serial port itself. In this configuration, the maximum number of EPROM bits that can be programmed simultaneously is four on a typical serial port. For higher performance, the above mentioned 12V auxiliary supply can be plugged into the power jack on the DS9097E and with proper software enable the serial port to program up to eight EPROM bits simultaneously.
Key Features
Provides a simple, low-cost interface to an RS-232C COM Port for reading and writing iButton devices (DS9097E required for programming DS198x Add-Only iButtons)
Adapter is powered entirely from an RS-232 interface (DS9097E may require optional auxiliary 12V supply)
Standard DB-9 (DSD9097) or DB-25 (DS9097E) female connector for mating the adapter to the COM Port of a computer and RJ-11 connector for easy attachment of a probe such as the DS9092GT
DS9097E has an additional 2.1mm male power jack to allow for an auxiliary 12V DC supply for programming add-only iButtons pin assignment DS9097, DB-9 TXD (3), RXD (2), DTR (4), PC-Ground (5); all other pins not connected Pin assignment DS9097E, DB-25 TXD (2), RXD (3), DTR (20), RTS (4), PC-Ground (7); all other pins not connected Auxiliary supply should be a 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)
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