at24hc04b ATMEL Corporation, at24hc04b Datasheet - Page 3

• Manufacturer Part Number: at24hc04b
• Description: Two-wire Serial Eeprom 4k 512 X 8
• Manufacturer: ATMEL Corporation

1. Pin Description
5227D–SEEPR–1/08
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/PAGE ADDRESSES (A2, A1, A0): The A2 and A1 pins are device address inputs that
must be hardwired for the AT24HC04B. As many as four 4K devices may be addressed on a
single bus system. The A0 pin is a no-connect. (Device addressing is discussed in detail under
Device Addressing,
WRITE PROTECT (WP): The AT24HC04B has a WP pin that provides hardware data protec-
tion. The WP pin allows normal read/write operations when connected to ground (GND). When
the WP pin is connected to V
Table 1-1.
WP Pin Status
At V
At GND
CC
Write Protect
page
8).
CC
, the write protection feature is enabled and operates as shown.
Normal Read/Write Operations
Part of the Array Protected
Upper Half (2K) Array
24HC04B
3