24LC32A/SM Microchip Technology, 24LC32A/SM Datasheet - Page 10
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24LC32A/SM
Manufacturer Part Number
24LC32A/SM
Description
IC EEPROM 32KBIT 400KHZ 8SOIC
Manufacturer
Microchip Technology
Specifications of 24LC32A/SM
Memory Size
32K (4K x 8)
Format - Memory
EEPROMs - Serial
Memory Type
EEPROM
Speed
400kHz
Interface
I²C, 2-Wire Serial
Voltage - Supply
2.5 V ~ 5.5 V
Operating Temperature
0°C ~ 70°C
Package / Case
8-SOIC (5.3mm Width), 8-SOP, 8-SOEIAJ
Memory Configuration
4K X 8
Ic Interface Type
I2C
Clock Frequency
400kHz
Supply Voltage Range
2.5V To 5.5V
Memory Case Style
SOIC
No. Of Pins
8
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
24AA32A/24LC32A
6.0
Read operations are initiated in the same way as write
operations, with the exception that the R/W bit of the
control byte is set to ‘1’. There are three basic types of
read operations: current address read, random read
and sequential read.
6.1
The 24XX32A contains an address counter that main-
tains the address of the last word accessed, internally
incremented by ‘1’. Therefore, if the previous read
access was to address ‘n’ (n is any legal address), the
next current address read operation would access data
from address n + 1.
Upon receipt of the control byte with R/W bit set to ‘1’,
the 24XX32A 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
24XX32A discontinues transmission (Figure 6-1).
6.2
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 accomplished by sending the word
address to the 24XX32A as part of a write operation
(R/W bit set to ‘0’). 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 issues the control byte again, but with the R/W
bit set to a ‘1’. The 24XX32A will then issue an
acknowledge and transmit the 8-bit data word. The
master will not acknowledge the transfer, but does
generate a Stop condition which causes the 24XX32A
to discontinue transmission (Figure 6-2). After a
random Read command, the internal address counter
will point to the address location following the one that
was just read.
FIGURE 6-1:
DS21713H-page 10
READ OPERATION
Current Address Read
Random Read
Bus Activity
Master
SDA Line
Bus Activity
CURRENT ADDRESS READ
S
T
A
R
T
S
Control
Byte
6.3
Sequential reads are initiated in the same way as a
random read, except that once the 24XX32A transmits
the first data byte, the master issues an acknowledge
as opposed to the Stop condition used in a random
read. This acknowledge directs the 24XX32A to
transmit the next sequentially addressed 8-bit word
(Figure 6-3). Following the final byte transmitted to the
master, the master will NOT generate an acknowledge,
but will generate a Stop condition. To provide sequen-
tial reads, the 24XX32A contains an internal Address
Pointer which is incremented by ‘1’ upon completion of
each operation. This Address Pointer allows the entire
memory contents to be serially read during one
operation. The internal Address Pointer will automati-
cally roll over from address FFF to address 000 if the
master acknowledges the byte received from the array
address FFF.
A
C
K
Sequential Read
Data (n)
© 2007 Microchip Technology Inc.
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