The DS2401 Enhanced Silicon Serial Number is a low-cost electronic registration number that provides an absolutely unique identity that can be determined with a minimal electronic interface (usually, a single-port pinout of a microcontroller). The DS2401 consists of a factory laser's 64-bit ROM, including a unique 48-bit serial number, an 8-bit CRC, and an 8-bit family code (01h). Data is transmitted serially over the 1-Wire protocol, requiring only one data line and a ground return. The power to read and write to the device is derived from the data cable itself, requiring no external power supply. The DS2401 is an upgraded product of the DS2400. The DS2401 is fully backward compatible with the DS2400, but provides additional multipoint capabilities that allow many devices to reside on a single data line. Familiar TO-92 , SOT-223 or TSOC packages provide compact enclosures that allow standard assembly of equipment and easy handling of equipment.

figure 1

The internal ROM of the DS2401 can be accessed through a single data line. 48-bit serial number, 8-bit serial retrieval code and 8-bit CRC using the Maxim 1-Wire protocol. This protocol defines the transactions of the bus based on the bus state during specified time slots initiated by the falling edge of the synchronization pulse from the bus master. The least significant bits of all data are read and written first. 1-Wire Bus System The 1-Wire bus is a system with a single bus master and one or more slaves. In all cases, the DS2401 is the slave device. The bus master is usually a microcontroller. The discussion system for this bus is divided into three topics: hardware configuration, transaction sequence, and 1-Wire signaling (signal types and timing).

figure 2

Hardware Configuration

By definition, a 1-Wire bus has only one wire; it is important that every device on the bus is able to drive at the appropriate time. For convenience, each device connected to the 1-Wire bus must have an open-drain connection or a tri-state output. The DS2401 is an open-drain part with an internal circuit equivalent to that shown in Figure 2. The bus master can be the same equivalent circuit. If bidirectional pins are not available, separate output and input pins can be connected together. The bus master needs to pull up the resistance of the bus master, and the bus master circuit is equivalent to the circuit shown in Figure 3. For short line lengths, the value of the pull-up resistor should be about 5kΩ. A multidrop bus consists of a 1-Wire bus and multiple slave connections. The maximum data rate of the 1-Wire bus is 16.3kbits per second. The idle state of the 1-Wire bus is high. If, for some reason, trading needs to be suspended, the bus must remain idle if it is to resume trading. If this does not happen and the bus is held low for more than 120 μs, one or more devices on the bus may reset.

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main feature

Guaranteed unique 64-bit ROM ID chip for absolute traceability

Unique, factory laser and tested 64-bit registration code (8-digit family code + 48-digit serial number + 8-digit CRC checker)

The 8-digit serial code specifies the communication requirements of the DS2401 to the reader

Minimalist 1-Wire® Interface Lower Cost and Interface Complexity

Multiple DS2401 devices can reside on a common 1-Wire network

Built-in multipoint controller ensures compatibility with other 1-Wire networking products

Reduce control, address, data and power to a single pin and communicate at up to 16.3kbps

When the reader first applies voltage, there is a pulse confirmation

Low cost TO-92, SOT-223 and TSOC surface mount packages

TO-92 Tape and Reel with leads bent to 100 mil pitch (default) or straight leads (DS2401-SL)

Wide voltage and temperature operating range for robust system performance

Extended 2.8V to 6.0V Range

Requires zero backup power

-40°C to +85°C industrial temperature range