IS25CD025

Integrated Silicon Solution, Inc.- www.issi.com

Rev. G

07/31/2013

4

SPI MODES DESCRIPTION

Multiple IS25CD025 devices can be connected on the

SPI serial bus and controlled by a SPI Master, i.e.

microcontroller, as shown in Figure 1. The devices

support either of two SPI modes:

Mode 0 (0, 0)

Mode 3 (1, 1)

The difference between these two modes is the clock

polarity when the SPI master is in Stand-by mode: the

serial clock remains at “0” (SCK = 0) for Mode 0 and

the clock remains at “1” (SCK = 1) for Mode 3. Please

refer to Figure 2. For both modes, the input data is

latched on the rising edge of Serial Clock (SCK), and

the output data is available from the falling edge of

SCK.

Figure 1. Connection Diagram among SPI Master and SPI Slaves (Memory Devices)

Figure 2. SPI Modes Supported

MSb

MSb

SCK

SCK

SO

SIO

Input mode

Mode 0 (0, 0)

Mode 3 (1, 1)

SPI Master

(i.e. Microcontroller)

CS3

CS2

CS1

SPI Memory

Device

SPI Memory

Devic

e

SPI Memory

Device

SPI Interface with

(0,0) or (1,1)

SDIO

SDI

SCK

SCK

SCK

SCK

SO

SO

SO

SIO

SIO

SIO

CE#

CE#

CE#

WP#

WP#

WP#

HOLD#

HOLD#

HOLD#

Note: 1. The Write Protect (WP#) and Hold (HOLD#) signals should be driven high or low as

appropriate.