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参数资料
| 型号： | DS2423P/T&R |
| 厂商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分类： | Memory IC:Other |
| 英文描述： | SPECIALTY MEMORY CIRCUIT, PDSO6 |
| 封装： | 3.70 X 4 MM, 1.50 MM HEIGHT, TSOC-6 |
| 文件页数： | 14/25页 |
| 文件大小： | 581K |
| 代理商： | DS2423P/T&R |
DS2423
21 of 25
Read-Data Time Slot
RESISTOR
MASTER
DS2423
tREC
VPUP
VPUPMIN
VIHMIN
VILMAX
0V
Master
Sampling
Window
tLOWR
tSLOT
tSU
tRDV
tRELEASE
CRC GENERATION
With the DS2423 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 DS2423 to
determine if the ROM data has been received error-free by the bus master. The equivalent polynomial
function of this CRC is: X8 + X5 + X4 + 1. This 8-bit CRC is received in the true (non-inverted) form
when reading the ROM of the DS2423. It is computed at the factory and lasered into the ROM.
The other CRC is a 16-bit type, generated according to the standardized CRC16-polynomial function x16
+ x15 + x2 + 1. This CRC is used for error detection when reading Data Memory using the Read Memory
+ Counter command and for fast verification of a data transfer when writing to the scratchpad. It is the
same type of CRC as is used with NV RAM based iButtons for error detection within the iButton
Extended File Structure. In contrast to the 8-bit CRC, the 16-bit CRC is always returned or sent in the
complemented (inverted) form. A CRC-generator inside the DS2423 chip (Figure 12) will calculate a new
16-bit CRC as shown in the command flow chart of Figure 7. The bus master compares the CRC value
read from the device to the one it calculates from the data and decides whether to continue with an
operation or re-read the portion of the data with the CRC error.
With the initial pass through the Read Memory + Counter 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, data bytes,
value of the counter associated with the page and zero bits. Subsequent passes through the Read Memory
+ Counter flow chart will generate a 16-bit CRC that is the result of clearing the CRC generator and then
shifting in the data bytes, the value of the counter and the zero bits.
With the Write Scratchpad command the CRC is generated by first clearing the CRC generator and then
shifting in the command code, the Target Addresses TA1 and TA2 and all the data bytes. The DS2423
will transmit this CRC only if the data bytes written to the scratchpad include scratchpad ending offset
11111b. The data may start at any location within the scratchpad.
For more details on generating CRC values including example implementations in both hardware and
software, see Application Note 27.
iButton is a registered trademark of Dallas Semiconductor, a wholly owned subsidiary of Maxim Integrated Products Inc.
Not
Recommended
for
New
Design
相关PDF资料 |
PDF描述 |
|---|---|
| DS2423P | SPECIALTY MEMORY CIRCUIT, PDSO6 |
| DS2423X | SPECIALTY MEMORY CIRCUIT, UUC |
| DS2423 | 4K X 1 STANDARD SRAM, PDSO6 |
| DS2422 | 1K X 1 STANDARD SRAM, PDSO6 |
| DS2430AP | 256 X 1 1-WIRE SERIAL EEPROM, PDSO6 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| DS2423V | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Serial SRAM |
| DS2423X | 功能描述:静态随机存取存储器 RoHS:否 制造商:Cypress Semiconductor 存储容量:16 Mbit 组织:1 M x 16 访问时间:55 ns 电源电压-最大:3.6 V 电源电压-最小:2.2 V 最大工作电流:22 uA 最大工作温度:+ 85 C 最小工作温度:- 40 C 安装风格:SMD/SMT 封装 / 箱体:TSOP-48 封装:Tray |
| DS243 | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Analog IC |
| DS2430 | 制造商:DALLAS 制造商全称:Dallas Semiconductor 功能描述:256-Bit 1-Wire EEPROM |
| DS2430A | 功能描述:电可擦除可编程只读存储器 RoHS:否 制造商:Atmel 存储容量:2 Kbit 组织:256 B x 8 数据保留:100 yr 最大时钟频率:1000 KHz 最大工作电流:6 uA 工作电源电压:1.7 V to 5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 |
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