AT24C128C-SSHM-T Datasheet, PDF (3/22 Pages) ATMEL Corporation – I2C-Compatible (2-Wire) Serial EEPROM 128-Kbit (16,384 x 8)

3. Block Diagram
V_CC
GND
WP
SCL
SDA
A₂
A₁
A₀
Start
Stop
Logic
LOAD
Device
Address
Comparator
Serial
Control
Logic
COMP
LOAD INC
EN _{H.V. Pump/Timing}
Data Recovery
R/W
Data Word
Addr/Counter
EEPROM
D_IN
D_OUT
Y DEC
Serial MUX
D_OUT/ACK
LOGIC
4. Pin Descriptions
Serial Clock (SCL): The SCL input is used to positive-edge clock data into each EEPROM device and negative-edge
clock data out of each device.
Serial Data (SDA): The SDA pin is bidirectional for serial data transfer. This pin is open drain driven and may be
wire-ORed with any number of other open-drain or open-collector devices.
Device Addresses (A₂, A₁, A₀): The A₂, A₁, and A₀ pins are device address inputs that are hard wired (directly to GND
or to V_CC) for compatibility with other Atmel AT24C devices. When the pins are hard wired, as many as eight 128K
devices may be addressed on a single bus system. (Device addressing is discussed in detail in Section 7. “Device
Addressing” on page 9). A device is selected when a corresponding hardware and software match is true. If these pins
are left floating, the A₂, A₁, and A₀ pins will be internally pulled down to GND. However, due to capacitive coupling that
may appear during customer applications, Atmel recommends always connecting the address pins to a known state.
When using a pull-up resistor, Atmel recommends using 10k or less.
Write Protect (WP): The Write Protect input, when connected to GND, allows normal write operations. When WP is
connected directly to V_CC, all write operations to the memory are inhibited. If the pin is left floating, the WP pin will be
internally pulled down to GND. However, due to capacitive coupling that may appear during customer applications, Atmel
recommends always connecting the WP pins to a known state. When using a pull-up resistor, Atmel recommends using
10k or less.
Table 4-1. Write Protect
WP Pin
Status
At V_CC
At GND
Part of the Array Protected
Atmel AT24C128C
Full Array
Normal Read/Write Operations
Atmel AT24C128C [DATASHEET]
3
8734B–SEEPR–9/2012