The DS2480B is a serial port to 1-Wire® interface chip that supports standard and overdrive speeds. It connects directly to UARTs and 5V RS-232 systems. Interfacing to RS-232C (±12V levels) requires a passive clamping circuit and one 5V to ±12V level translator. Internal timers relieve the host of the burden of generating the time-critical 1-Wire communication waveforms. In contrast to the DS9097(E) where a full character must be sent by the host for each 1-Wire time slot, the DS2480B can translate each character into eight 1-Wire time slots, thereby increasing the data throughput significantly. In addition, the DS2480B can be set to communicate at four different data rates, including 115.2kbps, 57.6kbps, and 19.2kbps, with 9.6kbps being the power-on default. Command codes received from the host's crystal controlled UART serve as a reference to continuously calibrate the on-chip timing generator. The DS2480B uses a unique protocol that merges data and control information without requiring control pins. This approach maintains compatibility to off-the-shelf serial to wireless converters, allowing easy realization of 1-Wire media jumpers. The various control functions of the DS2480B are optimized for 1-Wire networks and support the special needs of all current 1-Wire devices including EPROM-based add-only memories, EEPROM devices, and 1-Wire thermometers. See Application Note 192: Using the DS2480B Serial 1-Wire Driver for detailed software examples.
Key Features
Universal, Common-Ground Serial Port to 1-Wire Line Driver
Works with All iButton® and 1-Wire Slave Devices
Communicates at Standard and Overdrive 1-Wire speed and Serial Port Data Rates of 9600 (default), 19200, 57600, and 115200 bps
Supports 12V EPROM Programming and Stiff 5V Pullup for Sensors and EEPROM
Self-Calibrating Time Base with ±5% Tolerance for Serial and 1-Wire Communication
Slew Rate Controlled 1-Wire Pulldown and Active Pullup to Accommodate Long Lines and Reduce Radiation
User-Selectable RXD/TXD Polarity Minimizes Component Count When Interfacing to 5V Based RS-232 Systems or Directly to UARTs
Programmable 1-Wire Timing and Driver Characteristics Accommodate a Wide Range of Slave Device Configurations at Standard Speed
Smart Protocol Combines Data and Control Information Without Requiring Extra Pins
Compatible with Optical, IR, and RF to RS-232 Converters
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