is24c02a Integrated Silicon Solution, Inc., is24c02a Datasheet - Page 8
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is24c02a
Manufacturer Part Number
is24c02a
Description
Serial Eeprom
Manufacturer
Integrated Silicon Solution, Inc.
Datasheet
1.IS24C02A.pdf
(22 pages)
Available stocks
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Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
is24c02a-25LI
Manufacturer:
AVAGO
Quantity:
547
IS24C02A IS24C04A IS24C08A IS24C16A
8
READ OPERATIOn
Read operations are initiated in the same manner as
Write operations, except that the (R/W) bit of the Slave
address is set to “1”. There are three Read operation
options: current address read, random address read and
sequential read.
Current Address Read
The IS24C02A/04A/08A/16A contains an internal address
counter which maintains the address of the last byte
accessed, incremented by one. For example, if the previous
operation is either a Read or Write operation addressed to
the address location n, the internal address counter would
increment to address location n+1. When the EEPROM
receives the Slave Addressing Byte with a Read operation
(R/W bit set to “1”), it will respond an ACK and transmit the
8-bit data byte stored at address location n+1. The Master
should not acknowledge the transfer but should generate a
Stop condition so the IS24C02A/04A/08A/16A discontinues
transmission. If 'n' is the last byte of the memory, the data
from location '0' will be transmitted. (Refer to Figure 8.
Current Address Read Diagram.)
Random Address Read
Selective Read operations allow the Master device to select
at random any memory location for a Read operation. The
Master device first performs a 'dummy' Write operation
by sending the Start condition, Slave address and
byte address of the location it wishes to read. After the
IS24C02A/04A/08A/16A acknowledges the byte address,
the Master device resends the Start condition and the
Slave address, this time with the R/W bit set to one. The
EEPROM then responds with its ACK and sends the data
requested. The Master device does not send an ACK but
will generate a Stop condition. (Refer to Figure 9. Random
Address Read Diagram.)
Sequential Read
Sequential Reads can be initiated as either a Current
Address Read or Random Address Read. After the
IS24C02A/04A/08A/16A sends the initial byte sequence,
the Master device now responds with an ACK indicating it
requires additional data from the IS24C02A/04A/08A/16A.
The EEPROM continues to output data for each ACK
received. The Master device terminates the sequential
Read operation by pulling SDA High (no ACK) indicating the
last data word to be read, followed by a Stop condition.
The data output is sequential, with the data from address
n followed by the data from address n+1,n+2 ... etc. The
address counter increments by one automatically, allowing
the entire memory contents to be serially read during
sequential Read operation. When the memory address
boundary of 255, 511, 1023, or 2047 (depending on the
device) is reached, the address counter “rolls over” to
address 0, and the device continues to output data. (Refer
to Figure 10. Sequential Read Diagram).
Integrated Silicon Solution, Inc. — www.issi.com
11/10/08
Rev. J