X25C02

2

PIN DESCRIPTIONS

Serial Output (SO)

SO is a push/pull serial data output pin. During a read

cycle, data is shifted out on this pin. Data is clocked out

by the falling edge of the serial clock.

Serial Input (SI)

SI is the serial data input pin. All data, opcodes, byte

addresses, and data to be written to the memory are

input on this pin. Data is latched by the rising edge of the

serial clock.

Serial Clock (SCK)

The Serial Clock controls the serial bus timing for data

input and output. Opcodes, addresses, or data present

on the SI pin are sampled or latched on the rising edge

of the clock input, while data on the SO pin change after

the falling edge of the clock input.

Chip Select (

CS)

When

CS is HIGH, the X25C02 is deselected and the

SO output pin is at HIGH impedance and unless an

internal write operation is underway, the X25C02 will be

in the standby power mode.

CS LOW enables the

X25C02, placing it in the active power mode. It should be

noted that after power-up, a HIGH to LOW transition on

CS is required prior to the start of any operation.

Write Protect (

WP)

When

WP is LOW, nonvolatile writes to the X25C02 are

disabled, but the part otherwise functions normally.

When

WP is held HIGH, all functions, including nonvola-

tile writes operate normally.

WP going LOW while CS is

still LOW will interrupt a write to the X25C02. If the

internal write cycle has already been initiated,

WP going

LOW will have no affect on a write.

Hold (

HOLD)

HOLD is used in conjunction with the CS pin to select the

device. Once the part is selected and a serial sequence is

underway,

HOLD may be used to pause the serial

communication with the controller without resetting

the serial sequence. To pause,

HOLD must be brought

LOW while SCK is LOW. To resume communication,

HOLD is brought HIGH, again while SCK is LOW. If the

pause feature is not used,

HOLD should be held HIGH

at all times.

PIN CONFIGURATION

PIN NAMES

Symbol

Description

CS

Chip Select Input

SO

Serial Output

SI

Serial Input

SCK

Serial Clock Input

WP

Write Protect Input

Ground

Supply Voltage

HOLD

Hold Input

3843 PGM T01

3843 FHD F02.2

CS

SO

WP

VSS

1

2

3

4

8

7

6

5

VCC

HOLD

SCK

SI

X25C02

MSOP/DIP/SOIC