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參數(shù)資料
| 型號(hào)： | DS1977-F5 |
| 英文描述： | 32KB EEPROM iButton |
| 中文描述： | 32KB的EEPROM的iButton的 |
| 文件頁(yè)數(shù)： | 3/16頁(yè) |
| 文件大?。?/td> | 102K |
| 代理商： | DS1977-F5 |
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1/31/03
Read Access Password, Addresses 7FC0h to 7FC7h
The Read Access Password provides access to the function Read Memory. No password applies
when reading from or writing to the scratchpad. If passwords are enabled (EPW = AAh, see
Password Control Register), the 64-bit data pattern that the 1-Wire master has to transmit with the
command flow is compared to the passwords stored in the DS1977 iButton. If the password
matches, access is granted.
Read/Write Access Password, Addresses 7FC8h to 7FCFh
The Read/Write Access Password provides access to the functions Read Memory and Copy
Scratchpad. No password applies when reading from or writing to the scratchpad. If passwords
are enabled (EPW = AAh, see Password Control Register), the 64-bit data pattern that the 1-Wire
master has to transmit with the command flow is compared to the passwords stored in the
DS1977 iButton. If the password matches, access is granted.
Setting up a password is done essentially in the same way as writing data to the user data
memory, only the address is different. Before changing passwords, disable passwords. When
setting up a password, make sure that all 8 bytes of the password are defined. Otherwise the new
password may be unknown. Since they are located in the same memory page, both passwords
can be redefined at the same time. Always verify the scratchpad before sending the copy
scratchpad command. Before enabling passwords, check whether the new password has been
successfully written to the EEPROM chip. See "Verify Password" command for details. After a
new password is successfully copied from the scratchpad to its memory location, erase the
scratchpad by filling it with new data. Otherwise a copy of the password will remain accessible
through the scratchpad until the iButton is disconnected from the 1-Wire line.
Password Control Register
ADDR
b7
7FD0h
b6
b5
b4
b3
b2
b1
b0
EPW
Bit Description
EPW: Enable Passwords
Bit(s)
b0 to
b7
Definition
This byte specifies whether the device will test the validity
of passwords. If the EPW bits form a pattern of
10101010 (AAh), the device will execute these
commands only if the correct password is transmitted. If
the EPW pattern is different from AAh, any data pattern
will be accepted as a valid password. Before enabling
passwords, passwords for read access as well as
read/write access need to be written to the password
registers. The power-on default pattern of EPW is
different from AAh.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| DS1982U | UniqueWare iButton |
| DS1985U | UniqueWare iButton |
| DS1986 | 64 kbit Add-Only iButton |
| DS1986-F3 | EPROM|256X32X8|BUTTON|METAL |
| DS1986F5 | EPROM|256X32X8|BUTTON|METAL |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1977-F5- | 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Password-Protected 32KB EEPROM iButton |
| DS1977-F5# | 功能描述:iButton Password-Protected 32KB EEPROM 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 |
| DS1977-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 |
| DS1981U-F3-1125+ | 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 |
| DS1981U-F3-114C+ | 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 |
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