M25P05

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SPI MODES

These devices can be driven by a microcontroller

with its SPI peripheral running in either of the two

following modes:

– CPOL=0, CPHA=0

– CPOL=1, CPHA=1

For these two modes, input data is latched in on

the rising edge of Serial Clock (C), and output data

is available from the falling edge of Serial Clock

(C).

The difference between the two modes, as shown

in Figure 5, is the clock polarity when the bus mas-

ter is in Stand-by mode and not transferring data:

– C remains at 0 for (CPOL=0, CPHA=0)

– C remains at 1 for (CPOL=1, CPHA=1)

Figure 4. Bus Master and Memory Devices on the SPI Bus

Note: 1. The Write Protect (W) and Hold (HOLD) signals should be driven, High or Low as appropriate.

Figure 5. SPI Modes Supported

AI03746C

Bus Master

(ST6, ST7, ST9,

ST10, Others)

SPI Memory

Device

SDO

SDI

SCK

CQD

S

SPI Memory

Device

CQD

S

SPI Memory

Device

CQD

S

CS3

CS2

CS1

SPI Interface with

(CPOL, CPHA) =

(0, 0) or (1, 1)

W

HOLD

W

HOLD

W

HOLD

AI01438

C

C

MSB

LSB

CPHA

D or Q

0

1

CPOL

0

1