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参数资料
| 型号： | 24LC256 |
| 厂商： | Microchip Technology Inc. |
| 英文描述： | 256K I 2 C ⑩ CMOS Serial EEPROM |
| 中文描述： | 256K的I 2 C⑩的CMOS串行EEPROM |
| 文件页数： | 9/12页 |
| 文件大小： | 181K |
| 代理商： | 24LC256 |
24AA256/24LC256
DS21203C-page 6
1998 Microchip Technology Inc.
5.0
DEVICE ADDRESSING
A control byte is the rst byte received following the
start condition from the master device (Figure 5-1). The
control byte consists of a 4-bit control code; for the
24xx256 this is set as 1010 binary for read and write
operations. The next three bits of the control byte are
the chip select bits (A2, A1, A0). The chip select bits
allow the use of up to eight 24xx256 devices on the
same bus and are used to select which device is
accessed. The chip select bits in the control byte must
correspond to the logic levels on the corresponding A2,
A1, and A0 pins for the device to respond. These bits
are in effect the three most signicant bits of the word
address.
The last bit of the control byte denes the operation to
be performed. When set to a one a read operation is
selected, and when set to a zero a write operation is
selected. The next two bytes received dene the
address of the rst data byte (Figure 5-2). Because
only A14…A0 are used, the upper address bit is a don’t
care bit. The upper address bits are transferred rst, fol-
lowed by the less signicant bits.
Following the start condition, the 24xx256 monitors the
SDA bus checking the control byte being transmitted.
Upon receiving a 1010 code and appropriate device
select bits, the slave device outputs an acknowledge
signal on the SDA line. Depending on the state of
the R/W bit, the 24xx256 will select a read or write
operation.
FIGURE 5-1:
CONTROL BYTE FORMAT
5.1
Contiguous Addressing Across
Multiple Devices
The chip select bits A2, A1, A0 can be used to expand
the contiguous address space for up to 2 Mbit
by adding up to eight 24xx256's on the same bus. In
this case, software can use A0 of the control byte as
address bit A15; A1, as address bit A16; and A2, as
address bit A17. It is not possible to read or write
across device boundaries.
FIGURE 5-2:
ADDRESS SEQUENCE BIT ASSIGNMENTS
1
0
1
0
A2
A1
A0
SACK
R/W
Control Code
Chip Select
Bits
Slave Address
Acknowledge Bit
Start Bit
Read/Write Bit
1
010
A
2
A
1
A
0 R/W
X
A
11
A
10
A
9
A
7
A
0
A
8
A
12
CONTROL BYTE
ADDRESS HIGH BYTE
ADDRESS LOW BYTE
CONTROL
CODE
CHIP
SELECT
BITS
X = Don’t Care Bit
A
13
A
14
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相关代理商/技术参数 |
参数描述 |
|---|---|
| 24LC256-E/MF | 功能描述:电可擦除可编程只读存储器 32kx8 - 2.5V 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 |
| 24LC256E/MS | 制造商:Microchip Technology 功能描述:EEPROM Serial-I2C 256K-Bit 32K x 8 3.3V/5V 8-Pin MSOP Tube |
| 24LC256-E/MS | 功能描述:电可擦除可编程只读存储器 32kx8 - 2.5V 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 |
| 24LC256-E/P | 功能描述:电可擦除可编程只读存储器 32kx8 - 2.5V 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 |
| 24LC256-E/SM | 功能描述:电可擦除可编程只读存储器 32kx8 - 2.5V 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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