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參數(shù)資料
| 型號(hào)： | DS1923 |
| 英文描述： | Hygrochron Temperature/Humidity Logger iButton with 8kB Data Log Memory |
| 文件頁數(shù)： | 28/52頁 |
| 文件大?。?/td> | 495K |
| 代理商： | DS1923 |
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DS1923: Hygrochron Temperature/Humidity Logger iButton with 8kB Data Log Memory
This CRC is generated using the CRC16 polynomial by first clearing the CRC generator and then shifting in the
command code (0Fh) of the Write Scratchpad command, the Target Addresses TA1 and TA2 as supplied by the
master and all the data bytes. If the ending offset is 11111b, the master may send 16 read time slots and will
receive the inverted CRC16 generated by the DS1923.
Note that both register pages are write-protected during a mission. Although the Write Scratchpad command will
work normally at any time, the subsequent copy scratchpad to a register page will fail during a mission.
Read Scratchpad Command [AAh]
This command is used to verify scratchpad data and target address. After issuing the Read Scratchpad command,
the master begins reading. The first 2 bytes will be the target address. The next byte will be the ending offset/data
status byte (E/S) followed by the scratchpad data beginning at the byte offset (T4:T0), as shown in Figure 8. The
master may continue reading data until the end of the scratchpad after which it will receive an inverted CRC16 of
the command code, Target Addresses TA1 and TA2, the E/S byte, and the scratchpad data starting at the target
address. After the CRC is read, the bus master will read logical 1s from the DS1923 until a reset pulse is issued.
Copy Scratchpad with Password [99h]
This command is used to copy data from the scratchpad to the writable memory sections. After issuing the Copy
Scratchpad command, the master must provide a 3-byte authorization pattern, which can be obtained by reading
the scratchpad for verification. This pattern must exactly match the data contained in the three address registers
(TA1, TA2, E/S, in that order). Next the master must transmit the 64-bit full-access password. If passwords are
enabled and the transmitted password is different from the stored full-access password, the Copy Scratchpad with
Password command will fail. Then the device stops communicating and waits for a reset pulse. If the password
was correct or if passwords were not enabled, the device tests the 3-byte authorization code. If the authorization
code pattern matches, the AA (Authorization Accepted) flag is set and the copy begins. A pattern of alternating 1s
and 0s are transmitted after the data has been copied until the master issues a reset pulse. While the copy is in
progress any attempt to reset the part is ignored. Copy typically takes 2μs per byte.
The data to be copied is determined by the three address registers. The scratchpad data from the beginning offset
through the ending offset will be copied, starting at the target address. The AA flag remains at logic 1 until it is
cleared by the next Write Scratchpad command. With suitable password, the copy scratchpad always functions for
the 16 pages of data memory and the 2 pages of calibration memory. While a mission is in progress, write attempts
to the register pages will not be successful. The AA bit (Authorization Accepted) remaining at 0 will indicate this.
Read Memory with Password and CRC [69h]
The Read Memory with CRC command is the general function to read from the device. This command generates
and transmits a 16-bit CRC following the last data byte of a memory page.
After having sent the command code of the Read Memory with CRC command, the bus master sends a 2-byte
address that indicates a starting byte location. Next the master must transmit one of the 64-bit passwords. If
passwords are enabled and the transmitted password does not match one of the stored passwords, the Read
Memory with Password and CRC command fails. The device will stop communicating and will wait for a reset
pulse. If the password was correct or if passwords were not enabled, the master reads data from the DS1923
beginning from the starting address and continuing until the end of a 32-byte page is reached. At that point the bus
master sends 16 additional read data time slots and receive the inverted 16-bit CRC. With subsequent read-data
time slots the master will receive data starting at the beginning of the next memory page followed again by the
CRC for that page. This sequence continues until the bus master resets the device. When trying to read the
passwords or memory areas that are marked as "reserved", the DS1923 transmits 00h or FFh bytes, respectively.
The CRC at the end of a 32-byte memory page is based on the data as it was transmitted.
With the initial pass through the Read Memory with CRC flow, 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 contents of the data
memory. Subsequent passes through the Read Memory with CRC flow will generate a 16-bit CRC that is the result
of clearing the CRC generator and then shifting in the contents of the data memory page. After the 16-bit CRC of
the last page is read, the bus master receives logical 1s from the DS1923 until a reset pulse is issued. The Read
Memory with CRC command sequence can be ended at any point by issuing a reset pulse.
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相關(guān)PDF資料 |
PDF描述 |
|---|---|
| DS1923-F5 | Hygrochron Temperature/Humidity Logger iButton with 8kB Data Log Memory |
| DS1990 | Serial Number iButton |
| DS1990A | Serial Number iButton |
| DS1990A-F5 | Serial Number iButton |
| DS1994L-F5 | 4kb Plus Time Memory iButton |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1923_1 | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Hygrochron Temperature/Humidity Logger iButton with 8kB Data Log Memory |
| DS1923_11 | 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Hygrochron Temperature/Humidity Logger |
| DS1923-F5 | 功能描述:iButton RoHS:否 存儲(chǔ)類型:SRAM 存儲(chǔ)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 Hygrochron Temp/Hum Logger w/8KB DataLog RoHS:否 存儲(chǔ)類型:SRAM 存儲(chǔ)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(chǔ)類型:SRAM 存儲(chǔ)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 |
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