DS9097E

The DS9097 COM Port Adapter is a simple, low-cost passive adapter which performs RS232C (±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 115.2  kbits/s in order to create the  1-Wire TM 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 RS232 port operating at 115.2 kbits/s is used to form a single 1-Wire time slot, the maximum effective 1-Wire transfer rate is 14.4  kbits/s (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.