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参数资料
| 型号： | DS1986-F3 |
| 厂商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分类： | Programmable ROM |
| 英文描述： | 64K X 1 OTPROM, MEDB2 |
| 封装： | MICROCAN-2 |
| 文件页数： | 17/28页 |
| 文件大小： | 680K |
| 代理商： | DS1986-F3 |
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DS1986
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The other CRC is a 16-bit type, generated according to the standardized CRC16-polynomial function X16
+ X15 + X2 + 1. This CRC is used to safeguard user-defined EPROM data when reading data memory or
status memory. It is the same type of CRC as is used with NVRAM based iButtons to safeguard data
packets of the iButton File Structure. In contrast to the 8-bit CRC, the 16-bit CRC is always returned in
the complemented (inverted) form. A CRC-generator inside the DS1986 chip (Figure 12) will calculate a
new 16-bit CRC at every situation shown in the command flow chart of Figure 5.
The DS1986 provides this CRC-value to the bus master to validate the transfer of command, address, and
data to and from the bus master. When reading the data memory of the DS1986 with the Read Memory
command, the 16-bit CRC is only transmitted as the end of the memory is reached. This CRC is
generated by clearing the CRC generator, shifting in the command, low address, high address and every
data byte starting at the first addressed memory location and continuing until the end of the implemented
data memory is reached.
When reading the status memory with the Read Status command, the 16-bit CRC is transmitted when the
end of each 8-byte page of the status memory is reached. At the initial pass through the Read Status flow
chart the 16-bit CRC will be generated by clearing the CRC generator, shifting in the command byte, low
address, high address and the data bytes beginning at the first addressed memory location and continuing
until the last byte of the addressed EPROM Status data page is reached. Subsequent passes through the
Read Status flow chart will generate a 16-bit CRC that is the result of clearing the CRC generator and
then shifting in the new data bytes starting at the first byte of the next page of the EPROM Status data
field and continuing until the last byte of the page is reached.
When reading the data memory of the DS1986 with the Extended Read Memory command, there are two
situations where a 16-bit CRC is transmitted. One 16-bit CRC follows each Redirection Byte, another 16-
bit CRC is received after the last byte of a memory data page is read. The CRC at the end of the memory
page is always the result of clearing the CRC generator and shifting in the data bytes beginning at the first
addressed memory location of the EPROM data page until the last byte of this page. With the initial pass
through the Extended Read Memory flow chart the 16-bit CRC value is the result of shifting the
command byte into the cleared CRC generator, followed by the two address bytes and the Redirection
Byte. Subsequent passes through the Extended Read Memory flow chart will generate a 16-bit CRC that
is the result of clearing the CRC generator and then shifting in the Redirection Byte only.
When writing to the DS1986 (either data memory or status memory), the bus master receives a 16-bit
CRC to verify the correctness of the data transfer before applying the programming pulse. With the initial
pass through the Write Memory/Status flow chart the 16-bit CRC will be generated by clearing the CRC-
generator, shifting in the command, address low, address high and the data byte. Subsequent passes
through the Write Memory/Status flow chart due to the DS1986 automatically incrementing its address
counter will generate an 16-bit CRC that is the result of loading (not shifting) the new (incremented)
address into the CRC generator and then shifting in the new data byte.
The comparison of CRC values and decision to continue with an operation are determined entirely by the
bus master. There is no circuitry on the DS1986 that prevents a command sequence from proceeding if
the CRC stored in or calculated by the DS1986 does not match the value generated by the bus master. For
more details on generating CRC values including example implementations in both hardware and
software, see the Book of DS19xx iButton Standards.
相关PDF资料 |
PDF描述 |
|---|---|
| DS1986-F5 | 64K X 1 OTPROM, MADB2 |
| DS1991L-F5 | SPECIALTY MEMORY CIRCUIT, MEDB2 |
| DS1994L-F5 | SPECIALTY MEMORY CIRCUIT, MRDB2 |
| DS1993L-F5 | SPECIALTY MEMORY CIRCUIT, MRDB2 |
| DS1992L-F5 | SPECIALTY MEMORY CIRCUIT, MRDB2 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| DS1986-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 |
| DS1986-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 |
| DS1986F5 | 制造商:未知厂家 制造商全称:未知厂家 功能描述:EPROM|256X32X8|BUTTON|METAL |
| DS1986-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 |
| DS1986-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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