參數(shù)資料
型號: 24AA52_05
廠商: Microchip Technology Inc.
元件分類: EEPROM
英文描述: 2K 2.2V I2C⑩ Serial EEPROM with Software Write-Protect
中文描述: ⑩2K 2.2伏的I2C串行EEPROM與軟件寫保護
文件頁數(shù): 11/28頁
文件大?。?/td> 350K
代理商: 24AA52_05
2005 Microchip Technology Inc.
DS21166J-page 11
24AA52/24LCS52
7.0
READ OPERATION
Read operations are initiated in the same way as write
operations, with the exception that the R/W bit of the
slave address is set to ‘
1
’. There are three basic types
of read operations: current address read, random read
and sequential read.
7.1
Current Address Read
The 24XXX52 contains an address counter that
maintains the address of the last word accessed, inter-
nally incremented by ‘
1
’. Therefore, if the previous
access (either a read or write operation) was to
address
n
, the next current address read operation
would access data from address
n+1
. Upon receipt of
the slave address with R/W bit set to ‘
1
’, the 24XXX52
issues an acknowledge and transmits the 8-bit data
word. The master will not acknowledge the transfer, but
does generate a Stop condition and the 24XXX52
discontinues transmission (Figure 7-1).
7.2
Random Read
Random read operations allow the master to access
any memory location in a random manner. To perform
this type of read operation, the word address must first
be set. This is done by sending the word address to the
24XXX52 as part of a write operation. Once the word
address is sent, the master generates a Start condition
following the acknowledge. This terminates the write
operation, but not before the internal Address Pointer is
set. The master then issues the control byte again, but
with the R/W bit set to a ‘
1
’. The 24XXX52 then issues
an acknowledge and transmits the 8-bit data word. The
master will not acknowledge the transfer, but does
generate a Stop condition and the 24XXX52
discontinues transmission (Figure 7-2).
7.3
Sequential Read
Sequential reads are initiated in the same way as a
random read, with the exception that after the 24XXX52
transmits the first data byte, the master issues an
acknowledge, as opposed to a Stop condition in a
random read. This directs the 24XXX52 to transmit the
next sequentially addressed 8-bit word (Figure 7-3).
To provide sequential reads, the 24XXX52 contains an
internal Address Pointer, which is incremented by one
at the completion of each operation. This Address
Pointer allows the entire memory contents to be serially
read during one operation.
7.4
Contiguous Addressing Across
Multiple Devices
The Chip Select bits (A2, A1, A0) can be used to
expand the contiguous address space for up to 16K bits
by adding up to eight 24XXX52 devices on the same
bus. In this case, software can use A0 of the control
byte as address bit A8; A1 as address bit A9, and A2
as address bit A10. It is not possible to sequentially
read across device boundaries.
7.5
Noise Protection and Brown-Out
The 24XXX52 employs a V
CC
threshold detector circuit
which disables the internal erase/write logic if the V
CC
is below 1.5V at nominal conditions.
The SCL and SDA inputs have Schmitt Trigger and
filter circuits which suppress noise spikes to assure
proper device operation, even on a noisy bus.
FIGURE 7-1:
CURRENT ADDRESS READ
S
P
Bus Activity
Master
SDA Line
Bus Activity
S
T
O
P
Control
Byte
Data (n)
A
C
K
N
O
A
C
K
S
T
A
R
T
相關(guān)PDF資料
PDF描述
24AA52TIP 2K 2.2V I2C Serial EEPROM with Software Write-Protect
24AA52TIPG 2K 2.2V I2C Serial EEPROM with Software Write-Protect
24AA52TISN 2K 2.2V I2C Serial EEPROM with Software Write-Protect
24AA52TISNG 2K 2.2V I2C Serial EEPROM with Software Write-Protect
24AA52TIST 2K 2.2V I2C Serial EEPROM with Software Write-Protect
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
24AA52-I/MC 功能描述:電可擦除可編程只讀存儲器 256x8 - 2.5V Industrial Temp RoHS:否 制造商:Atmel 存儲容量:2 Kbit 組織:256 B x 8 數(shù)據(jù)保留:100 yr 最大時鐘頻率:1000 KHz 最大工作電流:6 uA 工作電源電壓:1.7 V to 5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8
24AA52-I/MCG 功能描述:電可擦除可編程只讀存儲器 256x8 - 2.5V Industrial Temp RoHS:否 制造商:Atmel 存儲容量:2 Kbit 組織:256 B x 8 數(shù)據(jù)保留:100 yr 最大時鐘頻率:1000 KHz 最大工作電流:6 uA 工作電源電壓:1.7 V to 5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8
24AA52-I/MS 功能描述:電可擦除可編程只讀存儲器 256x8 - 1.8V RoHS:否 制造商:Atmel 存儲容量:2 Kbit 組織:256 B x 8 數(shù)據(jù)保留:100 yr 最大時鐘頻率:1000 KHz 最大工作電流:6 uA 工作電源電壓:1.7 V to 5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8
24AA52-I/MSG 功能描述:電可擦除可編程只讀存儲器 256x8 - 1.8V Lead Free Package RoHS:否 制造商:Atmel 存儲容量:2 Kbit 組織:256 B x 8 數(shù)據(jù)保留:100 yr 最大時鐘頻率:1000 KHz 最大工作電流:6 uA 工作電源電壓:1.7 V to 5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8
24AA52-I/P 功能描述:電可擦除可編程只讀存儲器 256x8 - 1.8V RoHS:否 制造商:Atmel 存儲容量:2 Kbit 組織:256 B x 8 數(shù)據(jù)保留:100 yr 最大時鐘頻率:1000 KHz 最大工作電流:6 uA 工作電源電壓:1.7 V to 5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8