AT24C32C/64C
2. Pin Description
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 or left not connected for hardware compatibility with other AT24CXX devices. When
the pins are hardwired, as many as eight 32K/64K devices may be addressed on a single bus
system (device addressing is discussed in detail under the Device Addressing section). If the
pins are left floating, the A2, A1 and A0 pins will be internally pulled down to GND if the capaci-
tive coupling to the circuit board VCC plane is <3pF. If coupling is >3pF, Atmel® recommends
connecting the address pins to GND.
WRITE PROTECT (WP): The write protect input, when connected to GND, allows normal write
operations. When WP is connected high to VCC, all write operations to the memory are inhibited.
If the pin is left floating, the WP pin will be internally pulled down to GND if the capacitive cou-
pling to the circuit board VCC plane is <3pF. If coupling is >3pF, Atmel recommends connecting
the pin to GND.
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5298A–SEEPR–1/08
ATMEL [ ATMEL ]
