X25401

1

SPI Serial AUTOSTORE™ NOVRAM

© Xicor, Inc. 1992, 1995, 1996 Patents Pending

Characteristics subject to change without notice

2051-1.5 8/1/97 T0/C0/D2 SH

DESCRIPTION

The Xicor X25401 is a serial 256 bit NOVRAM featuring

a static RAM configured 16 x 16, overlaid bit-by-bit with

Serial Peripheral Interface (SPI) and software protocol

allowing operation on a simple three-wire bus. The bus

signals are a clock input (SCK) plus separate data in (SI)

and data out (SO) lines. Access to the device is con-

trolled through a chip select (

CS) input, allowing any

number of devices to share the same bus.

The Xicor NOVRAM design allows data to be transferred

between the two memory arrays by means of software

commands or external hardware inputs. A store opera-

pleted in 2

µs or less.

The X25401 also includes the AUTOSTORE feature, a

user selectable feature that automatically performs a

Xicor NOVRAMs are designed for unlimited write opera-

and a minimum 1,000,000 store operations. Inherent data

retention is specified to be greater than 100 years.

FEATURES

—Automatically Performs a Store Operation

—Minimum I/O Interface

—SPI Mode (0,0 & 1,1) Serial Port Compatible

—Easily Interfaced to Microcontroller Ports

Functions

—Active Current: 10mA

—Standby Current: 50

—Store Cycles: 1,000,000

—Data Retention: 100 Years

256 Bit

X25401

16 x 16 Bit

AUTOSTORE™ NOVRAM is a trademark of Xicor, Inc.

COPS is a trademark of National Semiconductor Corp.

FUNCTIONAL DIAGRAM

NONVOLATILE

E

2

PROM

CONTROL

LOGIC

COLUMN

DECODE

ROW

DECODE

4-BIT

COUNTER

INSTRUCTION

DECODE

INSTRUCTION

REGISTER

CS (1)

SI (3)

SCK (2)

SO (4)

RECALL (6)

AS (7)

STATIC

RAM

256-BIT

2051 FHD F01

A V AILABLE

AN56