DS2480B
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 115.2 kbps, 57.6 kbps and 19.2
kbps with 9.6 kbps 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
MicroLAN 1-Wire networks and support the special needs of all current 1-Wire devices including the
crypto iButton, EPROM-based Add-Only Memories, EEPROM devices and 1-Wire Thermometers.
DETAILED PIN DESCRIPTION
PIN SYMBOL DESCRIPTION
1
2
GND
1-W
Ground Pin: common ground reference and ground return for 1-Wire bus
1–Wire Input/Output Pin: 1–Wire bus with slew–rate–controlled pulldown,
active pullup, ability to switch in VPP to program EPROM, and ability to switch
in VDD through a low–impedance path to program EEPROM, perform a
temperature conversion or operate the crypto iButton.
3
4
NC
VDD
No Connection Pin.
Power Input Pin: power supply for the chip and 1–Wire pullup voltage, 5V
±10%, must always be lower than VPP. VDD should be derived from VPP by a
separate voltage regulator. If EPROM programming is not required feed VDD
from VPP through a Schottky diode to get a 0.3V drop at VDD.
EPROM Programming Voltage: 12V supply input for EPROM programming.
If EPROM programming is not required, connect this pin directly to the system’s
5V supply.
5
VPP
6
7
8
POL
TXD
RXD
RXD/TXD Polarity Select: RXD/TXD polarity select; tied to GND for RS232
(12V or 5V) connection; tied to VDD for direct connection to UART chip.
Serial Data from UART: data input from host (inverted or true); maximum
voltage swing –0.3V to VDD + 0.3V; for logic thresholds see DC specifications.
Serial Data to UART: signal output to host; push–pull driver with CMOS
compatible levels; for true ±12V RS232 systems an external level translator must
be provided.
OVERVIEW
The DS2480B directly interfaces a 5V serial communication port with its lines TXD (transmit) and RXD
(receive) to a 1–Wire bus. In addition the device performs a speed conversion allowing the data rate at the
communication port to be different from the 1–Wire data rate. Several parameters relating to the 1–Wire
port and its timing as well as the communication speed at both the port and the 1–Wire bus are
configurable. The circuit to achieve these functions is outlined in Figure 1, Block Diagram.
The device gets its input data from the serial communication port of the host computer through pin TXD.
For compatibility with active–high as well as active–low systems, the incoming signal can be inverted by
means of the polarity input POL. The polarity chosen by hard–wiring the logic level of this pin is also
valid for the output pin RXD. If for minimizing the interface hardware an asymmetry between RXD and
TXD is desired, this can be achieved by setting the most significant bit of the Speed Control parameter to
a 1 (see Configuration Parameter Value Codes). With the MS bit of the speed control set to 1, the polarity
at TXD is still selected by the logic level at POL, but the polarity at RXD will be the opposite of what the
logic level at POL specifies.
2 of 30
101999
5秒后页面跳转
PCF8574资料解读：主要参数分析、引脚说明
AD637数据手册解读：主要特性、引脚及其功能解读、电气参数
ADUM1201资料手册解读：参数分析、引脚说明、应用分析
一文带你了解压敏电阻器在直流电路中的过压保护作用
微信公众号
抖音公众号
浙公网安备 33010502006866号 浙ICP备10014259号-119
营业执照ICP证
技术参数
数据手册
如果您发现信息不准确，
