收藏本站
DS28EC20: 20Kb 1-Wire EEPROM
OVERVIEW
The block diagram in Figure 1 shows the relationships between the major control and memory sections of the
DS28EC20. The DS28EC20 has four main data components: 1) 64-bit registration number, 2) 32-byte scratchpad,
3) eighty 32-byte pages of EEPROM, and 4) special function registers. The hierarchical structure of the 1-Wire
protocol is shown in Figure 2. The bus master must first provide one of the seven ROM (network) function
commands: 1) Read ROM, 2) Match ROM, 3) Search ROM, 4) Skip ROM, 5) Resume, 6) Overdrive Skip ROM, or
7) Overdrive Match ROM. Upon completion of an Overdrive ROM command byte executed at standard speed, the
device enters Overdrive mode where all subsequent communication occurs at a higher speed. For operation at
overdrive speed, the DS28EC20 requires V PUP to be 5V ±5%. The protocol required for these ROM function
commands is described in Figure 9. After a ROM function command is successfully executed, the memory
functions become accessible and the master may provide any one of the five memory function commands. The
protocol for these commands is described in Figure 7. All data is read and written least significant bit first.
Figure 2. Hierarchical Structure for 1-Wire Protocol
DS28EC20 Command Level:
1-Wire ROM Function
Commands (see Figure 9)
DS28EC20-Specific
Memory Function
Commands (see Figure 7)
Available
Commands:
Read ROM
Match ROM
Search ROM
Skip ROM
Resume
Overdrive Skip*
Overdrive Match*
Write Scratchpad
Read Scratchpad
Copy Scratchpad
Read Memory
Extended Read Mem.
Data Field
Affected:
64-bit Reg. #, RC-Flag
64-bit Reg. #, RC-Flag
64-bit Reg. #, RC-Flag
RC-Flag
RC-Flag
RC-Flag, OD-Flag
64-bit Reg. #, RC-Flag, OD-Flag
32-byte Scratchpad, Flags
32-byte Scratchpad
Data Memory, Register Page
Data Memory, Register Page
Data Memory, Register Page
and XOR gates as shown in Figure 4. The polynomial is X + X + X + 1. Additional information about the 1-Wire
CRC is available in Application Note 27 : Understanding and Using Cyclic Redundancy Checks with Maxim iButton
* For operation at overdrive speed, the DS28EC20 requires V PUP to be 5V ±5%.
64-BIT ROM
Each DS28EC20 contains a unique ROM code that is 64 bits long. The first 8 bits are a 1-Wire family code. The
next 48 bits are a unique serial number. The last 8 bits are a cyclic redundancy check (CRC) of the first 56 bits.
See Figure 3 for details. The 1-Wire CRC is generated using a polynomial generator consisting of a shift register
8 5 4
?
Products ( www.maximintegrated.com/AN27 ).
The shift register bits are initialized to 0. Then, starting with the least significant bit of the family code, one bit at a
time is shifted in. After the 8th bit of the family code has been entered, the serial number is entered. After the last
bit of the serial number has been entered, the shift register contains the CRC value. Shifting in the 8 bits of the
CRC returns the shift register to all 0s.
Figure 3. 64-Bit ROM
MSB
LSB
8-Bit
CRC Code
48-Bit Serial Number
8-Bit Family
Code (43h)
MSB
LSB
MSB
LSB
MSB
LSB
iButton is a registered trademark of Maxim Integrated Products, Inc.
7 of 27
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
DS301X KWIK-CHG DESIGNATION STRIP SGL
DS3030W-100# IC NVSRAM 256KBIT 100NS 256BGA
DS3045W-100# IC NVSRAM 1MBIT 100NS 256BGA
DS3050W-100# IC NVSRAM 4MBIT 100NS 256BGA
DS3065W-100# IC NVSRAM 8MBIT 100NS 256BGA
DS3065WP-100IND+ IC SRAM 3.3V 8MB 34POWERCAP MOD
DS3070W-100# IC NVSRAM 16MBIT 100NS 256BGA
DS321X KIT X-WIDE DESIGN STRIP VERT
相关代理商/技术参数
DS28EC20-224-BB+ 制造商:Maxim Integrated Products 功能描述:- Rail/Tube
DS28EC20P 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:DS28EC20_1203
DS28EC20P T 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:DS28EC20_1203
DS28EC20P+ 功能描述:电可擦除可编程只读存储器 20Kb 1-Wire 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
DS28EC20P+T 功能描述:电可擦除可编程只读存储器 20Kb 1-Wire 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
DS28EC20P-224-BB+T 制造商:Maxim Integrated Products 功能描述:- Tape and Reel
DS28EC20Q-A5A-5A+T 制造商:Maxim Integrated Products 功能描述:20KB 1-WIRE EEPROM - Tape and Reel
DS28EC20Q-A5A-5A+W 制造商:Maxim Integrated Products 功能描述:20KB 1-WIRE EEPROM - Rail/Tube