AT24C08SC_14 Datasheet, PDF (9/14 Pages) ATMEL Corporation – Schmitt Trigger, Filtered Inputs for Noise Suppression

AT24C01ASC/02SC/04SC/08SC/16SC
Read Operations
Figure 10. Random Read
will the EEPROM respond with a “0” (ACK), allowing the read or write sequence to
continue.
Read operations are initiated the same way as write operations, with the exception that
the read/write select bit in the device address word is set to “1”. There are three read
operations: current address read, random address read, and sequential read.
CURRENT ADDRESS READ: The internal data word address counter maintains the
last address accessed during the last read or write operation, incremented by one. This
address stays valid between operations as long as the chip power is maintained. The
address “rollover” during read is from the last byte of the last memory page to the first
byte of the first page. The address “rollover” during write is from the last byte of the cur-
rent page to the first byte of the same page.
Once the device address with the read/write select bit set to “1” is clocked in and
acknowledged by the EEPROM, the current address data word is serially clocked out.
The microcontroller does not respond with an input “0” but does generate a following
stop condition (refer to Figure 9)
Figure 9. Current Address Read.
S
T
R
A
E
R
DEVICE
A
T ^ADDRESS
D
SDA LINE
M
LRA
DATA
N
S
S/C
O
B
BWK
A
C
K
RANDOM READ: A random read requires a “dummy” byte write sequence to load in the
data word address. Once the device address word and data word address are clocked
in and acknowledged by the EEPROM, the microcontroller must generate another start
condition. The microcontroller now initiates a current address read by sending a device
address with the read/write select bit high. The EEPROM acknowledges the device
address and serially clocks out the data word. The microcontroller does not respond
with a “0” (NO ACK) but does generate a following stop condition (refer to Figure 10).
WORD
ADDRESS n
LA M
L
SC S
S
BK B
B
Note: * = DON’T CARE bit for 1K)
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1610B–SEEPR–04/04