This Data Sheet may be revised by subsequent versions

©2004 Eon Silicon Solution, Inc., www.essi.com.tw

or modifications due to changes in technical specifications.

3

EN25P20

Rev. D, Issue Date: 2007/05/07

SIGNAL DESCRIPTION

Serial Data Input (DI)

The SPI Serial Data Input (DI) pin provides a means for instructions, addresses and data to be

serially written to (shifted into) the device. Data is latched on the rising edge of the Serial Clock (CLK)

input pin.

Serial Data Output (DO)

The SPI Serial Data Output (DO) pin provides a means for data and status to be serially read from

(shifted out of) the device. Data is shifted out on the falling edge of the Serial Clock (CLK) input pin.

Serial Clock (CLK)

The SPI Serial Clock Input (CLK) pin provides the timing for serial input and output operations. ("See

SPI Mode")

Chip Select (CS#)

The SPI Chip Select (CS#) pin enables and disables device operation. When CS# is high the device

is deselected and the Serial Data Output (DO) pin is at high impedance. When deselected, the

devices power consumption will be at standby levels unless an internal erase, program or status

register cycle is in progress. When CS# is brought low the device will be selected, power

consumption will increase to active levels and instructions can be written to and data read from the

device. After power-up, CS# must transition from high to low before a new instruction will be

accepted.

Hold (HOLD#)

The HOLD pin allows the device to be paused while it is actively selected. When HOLD is brought

low, while CS# is low, the DO pin will be at high impedance and signals on the DI and CLK pins will

be ignored (don’t care). The hold function can be useful when multiple devices are sharing the same

SPI signals.

Write Protect (WP#)

The Write Protect (WP#) pin can be used to prevent the Status Register from being written. Used

in conjunction with the Status Register’s Block Protect (BP0, BP1) bits and Status Register

Protect (SRP) bits, a portion or the entire memory array can be hardware protected.

Table 1. PIN Names

Symbol

Pin Name

CLK

Serial Clock Input

DI

Serial Data Input

DO

Serial Data Output

CS#

Chip Enable

WP#

Write Protect

HOLD#

Hold Input

Vcc

Supply Voltage (2.7-3.6V)

Vss

Ground