参数资料
型号: DS18S20-PAR
厂商: MAXIM INTEGRATED PRODUCTS INC
元件分类: Switch/Digital Output Temperature Sensor
英文描述: DIGITAL TEMP SENSOR-SERIAL, 9BIT(s), 0.50Cel, ROUND, THROUGH HOLE MOUNT
封装: TO-92, 3 PIN
文件页数: 17/20页
文件大小: 250K
代理商: DS18S20-PAR
DS18S20-PAR
6 of 20
DS18S20-PAR MEMORY MAP Figure 6
SCRATCHPAD (Power-up State)
byte 0 Temperature LSB (AAh)
byte 1 Temperature MSB (00h)
EEPROM
byte 2 TH Register or User Byte 1*
TH Register or User Byte 1
byte 3 TL Register or User Byte 2*
TL Register or User Byte 2
byte 4 Reserved (FFh)
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 9th byte 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 56th bit 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.”
CRC GENERATOR Figure 7
(MSB)
(LSB)
XOR
INPUT
(85°C)
相关PDF资料
PDF描述
DS18S20Z DIGITAL TEMP SENSOR-SERIAL, 9BIT(s), 0.50Cel, RECTANGULAR, SURFACE MOUNT
DS18S20 DIGITAL TEMP SENSOR-SERIAL, 9BIT(s), 0.50Cel, RECTANGULAR, THROUGH HOLE MOUNT
DS18S20-SL+T&R DIGITAL TEMP SENSOR-SERIAL, 9BIT(s), 0.50Cel, RECTANGULAR, THROUGH HOLE MOUNT
DS18S20Z/T&R DIGITAL TEMP SENSOR-SERIAL, 9BIT(s), 0.50Cel, RECTANGULAR, SURFACE MOUNT
DS1963L-F5 SPECIALTY MEMORY CIRCUIT, MEDB2
相关代理商/技术参数
参数描述
DS18S20-PAR/T&R 功能描述:板上安装温度传感器 RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor
DS18S20-PAR+T&R 制造商:Maxim Integrated Products 功能描述: 制造商:Maxim Integrated Products 功能描述:TEMP SENSOR DGTL 1-WIRE 3PIN TO-92 - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC THERM MICROLAN HI-PREC TO-92 制造商:Maxim Integrated Products 功能描述:Board Mount Temperature Sensors Prgmble Resolution 1-Wire Parasite Pwr
DS18S20-PAR+T&R 功能描述:板上安装温度传感器 Prgmble Resolution 1-Wire Parasite Pwr RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor
DS18S20-SL/T&R 功能描述:板上安装温度传感器 RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor
DS18S20-SL+T&R 制造商:Maxim Integrated Products 功能描述:TEMP SENSOR DGTL 1-WIRE - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC THERM MICROLAN HI-PREC TO-92 制造商:Maxim Integrated Products 功能描述:Board Mount Temperature Sensors Prgmble Resolution 1-Wire Parasite Pwr