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參數(shù)資料
| 型號： | DS1923-F5 |
| 英文描述： | Hygrochron Temperature/Humidity Logger iButton with 8kB Data Log Memory |
| 中文描述： | Hygrochron溫度/濕度記錄儀與8KB數(shù)據(jù)記錄存儲器iButton的 |
| 文件頁數(shù)： | 43/52頁 |
| 文件大?。?/td> | 495K |
| 代理商： | DS1923-F5 |
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DS1923: Hygrochron Temperature/Humidity Logger iButton with 8kB Data Log Memory
CRC GENERATION
With the DS1923 there are two different types of CRCs (Cyclic Redundancy Checks). One CRC is an 8-bit type
and is stored in the most significant byte of the 64-bit ROM. The bus master can compute a CRC value from the
first 56 bits of the 64-bit ROM and compare it to the value stored within the DS1923 to determine if the ROM data
has been received error-free. The equivalent polynomial function of this CRC is: X
+ X
+ X
+ 1. This 8-bit CRC is
received in the true (noninverted) form. It is computed at the factory and lasered into the ROM.
The other CRC is a 16-bit type, generated according to the standardized CRC16-polynomial function x
16
+ x
15
+ x
2
+ 1. This CRC is used for error detection when reading register pages or the data log memory using the Read
Memory with CRC command and for fast verification of a data transfer when writing to or
reading from the
scratchpad. In contrast to the 8-bit CRC, the 16-bit CRC is always communicated in the inverted form. A CRC
generator inside the DS1923 (Figure 15) calculates a new 16-bit CRC as shown in the command flow chart of
Figure 9. The bus master compares the CRC value read from the device to the one it calculates from the data and
decides whether to continue with an operation or to reread the portion of the data with the CRC error. With the
initial pass through the Read Memory with CRC flow chart, the 16-bit CRC value is the result of shifting the
command byte into the cleared CRC generator, followed by the 2 address bytes and the data bytes. The password
is excluded from the CRC calculation. Subsequent passes through the Read Memory with CRC flow chart generate
a 16-bit CRC that is the result of clearing the CRC generator and then shifting in the data bytes.
With the Write Scratchpad command the CRC is generated by first clearing the CRC generator and then shifting in
the command code, the Target Addresses, TA1 and TA2, and all the data bytes. The DS1923 transmits this CRC
only if the data bytes written to the scratchpad include scratchpad ending offset 11111b. The data can start at any
location within the scratchpad.
With the Read Scratchpad command the CRC is generated by first clearing the CRC generator and then shifting in
the command code, the Target Addresses, TA1 and TA2, the E/S byte, and the scratchpad data starting at the
target address. The DS1923 transmits this CRC only if the reading continues through the end of the scratchpad,
regardless of the actual ending offset. For more information on generating CRC values see the Dallas Application
Note 27.
Figure 15. CRC-16 HARDWARE DESCRIPTION AND POLYNOMIAL
Polynomial = X
16
+ X
15
+ X
2
+ 1
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16
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INPUT DATA
CRC
OUTPUT
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PDF描述 |
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| DS1990 | Serial Number iButton |
| DS1990A | Serial Number iButton |
| DS1990A-F5 | Serial Number iButton |
| DS1994L-F5 | 4kb Plus Time Memory iButton |
| DS1994 | 4kb Plus Time Memory iButton |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1923-F5# | 功能描述:iButton Hygrochron Temp/Hum Logger w/8KB DataLog RoHS:否 存儲類型:SRAM 存儲容量:512 B 組織: 工作電源電壓:3 V to 5.25 V 接口類型:1-Wire 最大工作溫度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封裝 / 箱體:F5 MicroCan 制造商:Maxim Integrated |
| DS1923-F5#W | 功能描述:iButton Hygrochron Temp/Hum Logger w/8KB DataLog RoHS:否 存儲類型:SRAM 存儲容量:512 B 組織: 工作電源電壓:3 V to 5.25 V 接口類型:1-Wire 最大工作溫度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封裝 / 箱體:F5 MicroCan 制造商:Maxim Integrated |
| DS1923-F5+ | 功能描述:iButton RoHS:否 存儲類型:SRAM 存儲容量:512 B 組織: 工作電源電壓:3 V to 5.25 V 接口類型:1-Wire 最大工作溫度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封裝 / 箱體:F5 MicroCan 制造商:Maxim Integrated |
| DS19310 | 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:Color TV Owners Manual Manuel dinstructions du teleouleur Color TV Manual Del Propietario |
| DS193-K | 制造商:Miyama Electric 功能描述: |
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