24LCS21 pdf datasheet

The Microchip Technology Inc. 24LCS21 is a 128 x 8-bit
dual-mode Electrically Erasable PROM. This device is
designed for use in applications requiring storage and
serial transmission of configuration and control information.
Two modes of operation have been implemented:
Transmit-only mode and Bidirectional mode. Upon
power-up, the device will be in the Transmit-only mode,
sending a serial bit stream of the entire memory array
contents, clocked by the VCLK pin. A valid high-to-low
transition on the SCL pin will cause the device to enter
the Bidirectional mode, with byte selectable read/write
capability of the memory array in standard I2C protocol.
The 24LCS21 also enables the user to write-protect the
entire memory contents using its write-protect pin. The
24LCS21 is available in a standard 8-pin PDIP and
SOIC package in both commercial and industrial
temperature ranges.