Abstract: This application note describes how to use the DS3900 PC serial port to 3-wire interface to communicate with the three digital pots, the DS1267, DS1867, and DS1868, which use this shift register interface for programming. The DS3900 is a module that has a MAX3223 RS-232 transceiver and a microprocessor which acts as an interface between the PC's serial port the 3-wire device being controlled. The transceiver allows the module’s microprocessor to communicate with a PC and the microprocessor implements a command structure, via its parallel port, to allow a PC to read or write the three digital potentiometers. The application note describes the DS3900 and how to interface it to the devices under test. The source code described in the article is available on Dallas Semiconductor’s FTP site. Maxim > App Notes > A/D and D/A CONVERSION/SAMPLING CIRCUITS DIGITAL POTENTIOMETERS GENERAL ENGINEERING TOPICS Keywords: DS1267, DS1867, DS1868, DS3900, 3-wire , digital pots, 3wire, digital potentiometers Aug 27, 2002 APPLICATION NOTE 213 Using a PC with a DS3900 to Communicate with DS1267s, DS1867s, and DS1868s Abstract: This application note describes how to use the DS3900 PC serial port to 3-wire interface to communicate with the three digital pots, the DS1267, DS1867, and DS1868, which use this shift register interface for programming. The DS3900 is a module that has a MAX3223 RS-232 transceiver and a microprocessor which acts as an interface between the PC's serial port the 3-wire device being controlled. The transceiver allows the module’s microproces……