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AT24C01C/02C [DATASHEET]
Atmel-8700H-SEEPROM-AT24C01C-02C-Datasheet_122016
7. Device Addressing
The 1-Kbit and 2-Kbit EEPROM device requires an 8-bit device address word following a Start condition to
enable the device for a Read or Write operation.
The device address word consists of a mandatory ‘1010’ (0xA) sequence for the first four most significant bits
as shown in Figure 7-1. This is common to all Serial EEPROM devices.
The next three bits are the A2, A1, and A0 device address bits for the 1K and 2K EEPROM. These three bits
must compare to their corresponding hard-wired input pins A2, A1, and A0 in order for the part to acknowledge.
The eighth bit of the device address is the Read/Write operation select bit. A Read operation is initiated if this bit
is high and a Write operation is initiated if this bit is low.
Upon a valid compare of the device address with hard-wired input pins A2, A1, and A0, the EEPROM will output
a zero. If a compare is not successfully made, the chip will return to a standby state.
Figure 7-1. Device Address
8. Write Operations
Byte Write: A Byte Write operation requires an 8-bit data word address following the device address word and
acknowledgment. Upon receipt of this address, the EEPROM will again respond with a zero and then clock in
the first 8-bit data word. Following receipt of the 8-bit data word, the EEPROM will output a zero and the
addressing device, such as a microcontroller, must terminate the write sequence with a Stop condition. At this
time, the EEPROM enters an internally timed write cycle, tWR, to the nonvolatile memory. All inputs are disabled
during this write cycle and the EEPROM will not respond until the write is complete.
Figure 8-1. Byte Write
Page Write: The 1-Kbit and 2-Kbit EEPROM are capable of an 8-byte Page Write.
A Page Write is initiated the same as a Byte Write, but the microcontroller does not send a Stop condition after
the first data word is clocked in. Instead, after the EEPROM acknowledges receipt of the first data word, the
microcontroller can transmit up to seven data words. The EEPROM will respond with a zero after each data
word received. The microcontroller must terminate the page write sequence with a Stop condition.
The data word address lower three bits are internally incremented following the receipt of each data word. The
higher data word address bits are not incremented, retaining the memory page row location. When the word
address, internally generated, reaches the page boundary, the following byte is placed at the beginning of the
same page. If more than eight data words are transmitted to the EEPROM, the data word address will “roll over”
and previous data will be overwritten.
1K or 2K 1 0 1 0 A2 A1 A0 R/W
MSB LSB
SDA LINE
S
T
A
R
T
W
R
I
T
E
S
T
O
P
Device
Address Word Address Data
M
S
B
A
C
K
A
C
K
A
C
K
R
/
W