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参数资料
| 型号： | DS1963S |
| 厂商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分类： | Memory IC:Other |
| 英文描述： | SPECIALTY MEMORY CIRCUIT, MEDB2 |
| 封装： | MICROCAN-2 |
| 文件页数： | 23/37页 |
| 文件大小： | 349K |
| 代理商： | DS1963S |
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DS1963S
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Note 1: The device provides functions to authenticate the host based on a system-wide secret, the
device’s ROM Registration number and a user-selected pin number that is installed in one of the
memory pages of a roaming data carrier.
Note 2: To find out whether a slave device is authentic the host writes a 3-byte “challenge” to the
scratchpad before issuing a command to compute the SHA-1 MAC over the challenge, the data
of a memory page, the page number, the page’s write-cycle counter, the device’s ROM
Registration number, and the secret associated with that page. By varying the challenge every
time it reads from a slave, the host can verify that the slave contains the correct secret and can
perform the required SHA computation in the required time.
Note 3: Manipulated data can be discovered if the data in the slave device is “signed” by an authorized
host. Signing consists of calculating a 160-bit SHA-1 MAC over the data to be protected, the
write-cycle counter of the page on which it is to be stored, the ROM ID of the slave device in
which it is to be stored, and any dedicated secret known only to authorized hosts. The MAC is
stored together with the application data (a monetary value together with a transaction ID code,
for example) in an appropriate memory page. To verify the authenticity of the data the host
repeats the process of signing. Any change in the data, the cycle counter, data carrier or an
invalid (not belonging to the system) signing-secret will make the verification of the signature
fail.
OVERVIEW
The block diagram in Figure 1 shows the relationships between the major control and memory sections of
the DS1963S. The DS1963S has six main data components: 1) 64-bit lasered ROM, 2) 256-bit scratch-
pad, 3) eight 32-byte pages of general-purpose SRAM, 4) eight 32-byte pages of SRAM protected by
write-cycle counters, 5) two 32-byte pages storing eight 64-bit secrets with individual write-cycle
counters, and 6) a 512-bit SHA-1 Engine (SHA = Secure Hash Algorithm). The hierarchical structure of
the 1-Wire protocol is shown in Figure 2. All write-cycle counters are 32 bits long and will not roll over
once the maximum count has been reached. The contents of the counters is read together with the
memory data using a special command. The bus master must first provide one of the seven ROM
Function Commands, 1) Read ROM, 2) Match ROM, 3) Search ROM, 4) Skip ROM, 5) Resume
Communication, 6) Overdrive-Skip ROM or 7) Overdrive-Match ROM. Upon completion of an
Overdrive ROM command byte executed at standard speed, the device will enter Overdrive mode where
all subsequent communication occurs at a higher speed. The protocol required for these ROM function
commands is described in Figure 10. After a ROM function command is successfully executed, the
memory functions become accessible and the master may provide any one of the eight memory function
commands. The protocol for these memory function commands is described in Figure 7. All data is read
and written least significant bit first.
PARASITE POWER
The block diagram (Figure 1) shows the parasite-powered circuitry. This circuitry “steals” energy
whenever the data contact is in the logic-high state. This stolen energy will provide sufficient power
while the data contact is in a logic-low state as long as the specified timing and voltage requirements are
met. The advantages of parasite power are two-fold: 1) by stealing energy off this input, the DS1963S-
internal lithium reserves are conserved and 2) if the lithium is exhausted for any reason, the ROM may
still be read normally. The remaining circuitry of the DS1963S is solely operated by lithium energy.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| DS1963S+F5 | 制造商:Maxim Integrated Products 功能描述:SHA IBTN 8SOIC - Rail/Tube |
| DS1963S-F5 | 功能描述:iButton RoHS:否 存储类型:SRAM 存储容量:512 B 组织: 工作电源电压:3 V to 5.25 V 接口类型:1-Wire 最大工作温度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封装 / 箱体:F5 MicroCan 制造商:Maxim Integrated |
| DS1963S-F5+ | 功能描述:iButton SHA iButton RoHS:否 存储类型:SRAM 存储容量:512 B 组织: 工作电源电压:3 V to 5.25 V 接口类型:1-Wire 最大工作温度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封装 / 箱体:F5 MicroCan 制造商:Maxim Integrated |
| DS1965S-1-F3 | 功能描述:iButton RoHS:否 存储类型:SRAM 存储容量:512 B 组织: 工作电源电压:3 V to 5.25 V 接口类型:1-Wire 最大工作温度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封装 / 箱体:F5 MicroCan 制造商:Maxim Integrated |
| DS1965S-1-F5 | 功能描述:iButton RoHS:否 存储类型:SRAM 存储容量:512 B 组织: 工作电源电压:3 V to 5.25 V 接口类型:1-Wire 最大工作温度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封装 / 箱体:F5 MicroCan 制造商:Maxim Integrated |
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