收藏本站

DS2505
PROGRAM PULSE TIMING DIAGRAM Figure 11
CRC GENERATION
With the DS2505 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 DS2505
to determine if the ROM data has been received error-free by the bus master. The equivalent polynomial
function of this CRC is: X 8 + X 5 + X 4 + 1. This 8-bit CRC is received in the true (non-inverted) form
when reading the ROM of the DS2505. It is computed once 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 to safeguard user-defined EPROM data when reading data memory or
status memory. It is the same type of CRC as is used with NV RAM 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 DS2505 chip (Figure 12) will calculate a
new 16-bit CRC at every situation shown in the command flow chart of Figure 5.
The DS2505 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 DS2505 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.
21 of 24
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
DS25LV02R+T&R IC OTP 1KBIT SOT23-5
DS2704G+T&R IC EEPROM 1.25KBIT 6TDFN
DS28CZ04G-4+T IC EEPROM 4KBIT 400KHZ 12TQFN
DS28DG02E-3C+T IC EEPROM 2KBIT 2MHZ 28TSSOP
DS28E04S-100+T IC EEPROM 4KBIT 16SOIC
DS28EC20+T IC EEPROM 20KBIT TO92-3
DS301X KWIK-CHG DESIGNATION STRIP SGL
DS3030W-100# IC NVSRAM 256KBIT 100NS 256BGA
相关代理商/技术参数
DS2505+TR 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:16Kb Add-Only Memory
DS2505010A6 制造商: 功能描述: 制造商:undefined 功能描述:
DS2505FRAB0 制造商:Thomas & Betts 功能描述:200A,REC,4P5W,MG,505,AB0,3P250/440
DS2505MP000 制造商:Thomas & Betts 功能描述:200A,PLG,4P5W,MG,505,3P250V
DS2505MRAB0 制造商:Thomas & Betts 功能描述:200A,NLT,4P5W,MG,505,AB0,3P250/440
DS2505P 功能描述:可擦除可编程ROM RoHS:否 制造商:Maxim Integrated 类型: 存储容量:1024 bit 组织:1 K x 1 接口类型: 工作电流:5 uA 编程电压: 工作电源电压:2.8 V to 6 V 最大工作温度:+ 85 C 安装风格:Through Hole 封装 / 箱体:TO-92
DS2505P/T&R 制造商:Maxim Integrated Products 功能描述:IC OTP 16KBIT 6TSOC
DS2505P/T&R 功能描述:可擦除可编程ROM RoHS:否 制造商:Maxim Integrated 类型: 存储容量:1024 bit 组织:1 K x 1 接口类型: 工作电流:5 uA 编程电压: 工作电源电压:2.8 V to 6 V 最大工作温度:+ 85 C 安装风格:Through Hole 封装 / 箱体:TO-92