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CAT24C256 Datasheet, PDF (8/14 Pages) Catalyst Semiconductor – 256-Kb I2C CMOS Serial EEPROM | |||
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CAT24C256
READ OPERATIONS
Immediate Address Read
In standby mode, the CAT24C256 internal address
counter points to the data byte immediately following the
last byte accessed by a previous operation. If that âprevi-
ousâ byte was the last byte in memory, then the address
counter will point to the 1st memory byte, etc.
When, following a START, the CAT24C256 is presented
with a Slave address containing a â1â in the R/W bit
position (Figure 8), it will acknowledge (ACK) in the 9th
clock cycle, and will then transmit data being pointed
at by the internal address counter. The Master can stop
further transmission by issuing a NoACK, followed by a
STOP condition.
Selective Read
The Read operation can also be started at an address
different from the one stored in the internal address
counter. The address counter can be initialized by per-
forming a âdummyâ Write operation (Figure 9). Here the
START is followed by the Slave address (with the R/W
bit set to â0â) and the desired two byte address. Instead
of following up with data, the Master then issues a 2nd
START, followed by the âImmediate Address Readâ se-
quence, as described earlier.
Sequential Read
If the Master acknowledges the 1st data byte transmitted
by the CAT24C256, then the device will continue trans-
mitting as long as each data byte is acknowledged by
the Master (Figure 10). If the end of memory is reached
during sequential Read, then the address counter will
âwrap-aroundâ to the beginning of memory, etc. Sequential
Read works with either âImmediate Address Readâ or
âSelective Readâ, the only difference being the starting
byte address.
Doc. No. 1104, Rev. D
© 2007 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
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