Datasheet > DS18S20-PAR

DS18S20-PAR

更新时间： 2023-12-20 18:44:36

品牌	Logo	应用领域
亚德诺 - ADI		/
页数	文件大小	规格书
20页	250K
描述
寄生供电数字温度计

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中文翻译

获取价格

数据手册

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DS18S20-PAR 数据手册

DS18S20-PAR

DS18S20-PAR MEMORY MAP Figure 6

SCRATCHPAD (Power-up State)

byte 0 Temperature LSB (AAh)

(85°C)

byte 1 Temperature MSB (00h)

byte 2 T_HRegister or User Byte 1*

byte 3 T_LRegister or User Byte 2*

byte 4 Reserved (FFh)

EEPROM

T_HRegister or User Byte 1

T_LRegister or User Byte 2

byte 5 Reserved (FFh)

byte 6 COUNT REMAIN (0Ch)

byte 7 COUNT PER °C (10h)

byte 8 CRC*

*Power-up state depends on value(s) stored

in EEPROM

CRC GENERATION

CRC bytes are provided as part of the DS18S20-PAR’s 64-bit ROM code and in the 9^thbyte of the

scratchpad memory. The ROM code CRC is calculated from the first 56 bits of the ROM code and is

contained in the most significant byte of the ROM. The scratchpad CRC is calculated from the data

stored in the scratchpad, and therefore it changes when the data in the scratchpad changes. The CRCs

provide the bus master with a method of data validation when data is read from the DS18S20-PAR. To

verify that data has been read correctly, the bus master must re-calculate the CRC from the received data

and then compare this value to either the ROM code CRC (for ROM reads) or to the scratchpad CRC (for

scratchpad reads). If the calculated CRC matches the read CRC, the data has been received error free. The

comparison of CRC values and the decision to continue with an operation are determined entirely by the

bus master. There is no circuitry inside the DS18S20-PAR that prevents a command sequence from

proceeding if the DS18S20-PAR CRC (ROM or scratchpad) does not match the value generated by the

bus master.

The equivalent polynomial function of the CRC (ROM or scratchpad) is:

CRC = X⁸+ X⁵+ X⁴+ 1

The bus master can re-calculate the CRC and compare it to the CRC values from the DS18S20-PAR

using the polynomial generator shown in Figure 7. This circuit consists of a shift register and XOR gates,

and the shift register bits are initialized to 0. Starting with the least significant bit of the ROM code or the

least significant bit of byte 0 in the scratchpad, one bit at a time should shifted into the shift register.

After shifting in the 56^thbit from the ROM or the most significant bit of byte 7 from the scratchpad, the

polynomial generator will contain the re-calculated CRC. Next, the 8-bit ROM code or scratchpad CRC

from the DS18S20-PAR must be shifted into the circuit. At this point, if the re-calculated CRC was

correct, the shift register will contain all 0s. Additional information about the Dallas 1-Wire cyclic

redundancy check is available in Application Note 27 entitled “Understanding and Using Cyclic

Redundancy Checks with Dallas Semiconductor Touch Memory Products.”

INPUT

CRC GENERATOR Figure 7

XOR

(MSB)

(LSB)

6 of 20

1...3 4 567 8 9...20

中文翻译

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与DS18S20-PAR相关器件

型号	品牌	获取价格	描述	数据表
DS18S20-PAR+T&R	MAXIM	获取价格	Serial Switch/Digital Sensor, 9 Bit(s), 0.50Cel, Round, Through Hole Mount, TO-92, 3 PIN
DS18S20-SL+T&R	MAXIM	获取价格	Serial Switch/Digital Sensor, 9 Bit(s), 0.50Cel, Rectangular, 3 Pin, Through Hole Mount, R
DS18S20Z	DALLAS	获取价格	High Precision 1-Wire Digital Thermometer
DS18S20Z	MAXIM	获取价格	Serial Switch/Digital Sensor, 9 Bit(s), 0.50Cel, Rectangular, 8 Pin, Surface Mount, SOP-8
DS18S20Z/T&R	MAXIM	获取价格	Serial Switch/Digital Sensor, 9 Bit(s), 0.50Cel, Rectangular, 8 Pin, Surface Mount, SOP-8
DS18S20Z+	MAXIM	获取价格	Serial Switch/Digital Sensor, 9 Bit(s), 0.50Cel, Rectangular, 8 Pin, Surface Mount, ROHS C
DS18S20Z+T&R	MAXIM	获取价格	Serial Switch/Digital Sensor, 9 Bit(s), 0.50Cel, Rectangular, 8 Pin, Surface Mount, ROHS C
DS18VN6FF100	BANNER	获取价格	DS18 Series Sensors
DS18VN6FF50	BANNER	获取价格	DS18 Series Sensors
DS18VN6LP	BANNER	获取价格	DS18 Series Sensors

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