24AA08/24LC08B
3.0
FUNCTIONAL DESCRIPTION
4.4
Data Valid (D)
The 24XX08 supports a bidirectional, 2-wire bus and
data transmission protocol. A device that sends data
onto the bus is defined as a transmitter, while a device
receiving data is defined as a receiver. The bus has to
be controlled by a master device which generates the
Serial Clock (SCL), controls the bus access and
generates the Start and Stop conditions, while the
24XX08 works as slave. Both master and slave can
operate as transmitter or receiver, but the master
device determines which mode is activated.
The state of the data line represents valid data when,
after a Start condition, the data line is stable for the
duration of the high period of the clock signal.
The data on the line must be changed during the low
period of the clock signal. There is one clock pulse per
bit of data.
Each data transfer is initiated with a Start condition and
terminated with a Stop condition. The number of the
data bytes transferred between the Start and Stop
conditions is determined by the master device and is
4.0
BUS CHARACTERISTICS
theoretically unlimited, although only the last sixteen
will be stored when doing a write operation. When an
The following bus protocol has been defined:
? Data transfer may be initiated only when the bus
is not busy.
? During data transfer, the data line must remain
stable whenever the clock line is high. Changes in
the data line while the clock line is high will be
interpreted as a Start or Stop condition.
Accordingly, the following bus conditions have been
overwrite does occur it will replace data in a first-in first-
out (FIFO) fashion.
4.5 Acknowledge
Each receiving device, when addressed, is obliged to
generate an acknowledge after the reception of each
byte. The master device must generate an extra clock
pulse which is associated with this Acknowledge bit.
defined ( Figure 4-1 ).
Note:
The 24XX08 does not generate any
Acknowledge bits if an internal program-
4.1
Bus Not Busy (A)
ming cycle is in progress.
Both data and clock lines remain high.
The device that acknowledges, has to pull down the
SDA line during the acknowledge clock pulse in such a
4.2
Start Data Transfer (B)
way that the SDA line is stable low during the high
period of the acknowledge related clock pulse. Of
A high-to-low transition of the SDA line while the clock
(SCL) is high determines a Start condition. All
commands must be preceded by a Start condition.
course, setup and hold times must be taken into
account. During reads, a master must signal an end of
data to the slave by not generating an Acknowledge bit
on the last byte that has been clocked out of the slave.
4.3
Stop Data Transfer (C)
In this case, the slave (24XX08) will leave the data line
high to enable the master to generate the Stop
A low-to-high transition of the SDA line while the clock
(SCL) is high determines a Stop condition. All
operations must be ended with a Stop condition.
condition.
FIGURE 4-1:
DATA TRANSFER SEQUENCE ON THE SERIAL BUS
SCL
(A)
(B)
(D)
(D)
(C)
(A)
SDA
Start
Condition
DS21710K-page 6
Address or
Acknowledge
Valid
Data
Allowed
to Change
Stop
Condition
? 2002-2012 Microchip Technology Inc.
相关PDF资料
24AA16-I/STG IC EEPROM 16KBIT 400KHZ 8TSSOP
24AA256-I/MS IC EEPROM 256KBIT 400KHZ 8MSOP
24AA32A/SN IC EEPROM 32KBIT 400KHZ 8SOIC
24AA32AF-I/SN IC SRL EEPROM 4KX8 1.8V 8-SOIC
24AA512-I/ST14 IC EEPROM 512KBIT 400KHZ 14TSSOP
24AA52T-I/MC IC EEPROM 2KBIT 400KHZ 8DFN
24AA64F-I/MS IC SRL EEPROM 8KX8 1.8V 8-MSOP
24AA65/P IC EEPROM 64KBIT 400KHZ 8DIP
相关代理商/技术参数
24AA08/WF15K 制造商:Microchip Technology Inc 功能描述:8K, 1K X 8 1.8V SERIAL EE WAFER ON FR - Gel-pak, waffle pack, wafer, diced wafer on film
24AA08_09 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:8K I2C? Serial EEPROM
24AA080 功能描述:整流器/与可变电容器 RED 1.8-6.0 PFD RoHS:否 制造商:Xicon 电容范围:2.8 pF to 12.5 pF 容差: 电压额定值:200 V 工作温度范围:- 35 C to + 85 C 端接类型:SMD/SMT 产品:Trimmer Capacitors - Ceramic Dielectric
24AA080-IP 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:8K/16K 1.8V SPI Bus Serial EEPROM
24AA080-ISN 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:8K/16K 1.8V SPI Bus Serial EEPROM
24AA080-P 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:8K/16K 1.8V SPI Bus Serial EEPROM
24AA080-SN 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:8K/16K 1.8V SPI Bus Serial EEPROM
24AA081 功能描述:整流器/与可变电容器 NO COLOR 2.8-12.5PFD RoHS:否 制造商:Xicon 电容范围:2.8 pF to 12.5 pF 容差: 电压额定值:200 V 工作温度范围:- 35 C to + 85 C 端接类型:SMD/SMT 产品:Trimmer Capacitors - Ceramic Dielectric