MAXIM DS2480B+T&R

The DS2480B is a serial port to 1-Wire interface chip that supports standard and overdrive speeds. It connects directly to UARTs and 5V RS232 systems. Interfacing to RS232C (±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 addonly memories, EEPROM devices, and 1-Wire thermometers.

• Simplifies the Design of a Low-Cost, Universal RS-232 COM Port to 1-Wire True-Ground
• Interface to an RS-232 COM Port for Reading and Writing 1-Wire Devices
• Works with Bipolar as well as Unipolar Logic Signals
• Slew Rate Controlled 1-Wire Pulldown and Active Pullup to Accommodate Long Lines and Reduce Radiation
• Communicates at Data Rates of 9.6kbps (default), 19.2kbps, 57.6kbps, and 115.2kbps
• Self-Calibrating Time Base with ±5% Tolerance for Serial and 1-Wire Communication
• User-Selectable RXD/TXD Polarity
• Minimizes Component Count When Interfacing to 5V Based RS232 Systems or Directly to UARTs
• Smart Protocol Combines Data and Control Information Without Requiring Extra Pins
• Compatible with Optical, IR, and RF to RS232 Converters
• Single Product Supports Various iButton or 1-Wire Device Types for Easy System Integration
• Supports Reading and Writing at Standard and Overdrive Speeds
• Provides Strong Pullup to 5V for Temperature and EEPROM 1-Wire Devices
• Programs 1-Wire EPROM Devices with External 12V Power Supply
• Programmable 1-Wire Timing and Driver Characteristics Accommodate a Wide Range of Slave Device Configurations at Standard Speed
• Operates Over 4.5V to 5.5V from -40°C to +85°C