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A25L40PTM-F

4 Mbit, Low Voltage, Serial Flash Memory With 85MHz SPI Bus Interface

AMIC Technology 

SIGNAL DESCRIPTION

Serial Data Output (Q). This output signal is used to transfer

data serially out of the device. Data is shifted out on the

falling edge of Serial Clock (C).

Serial Data Input (D). This input signal is used to transfer

data serially into the device. It receives instructions,

addresses, and the data to be programmed. Values are

latched on the rising edge of Serial Clock (C).

Serial Clock (C). This input signal provides the timing of the

serial interface. Instructions, addresses, or data present at

Serial Data Input (D) are latched on the rising edge of Serial

Clock (C). Data on Serial Data Output (Q) changes after the

falling edge of Serial Clock (C).

Chip Select ( S ). When this input signal is High, the device is

deselected and Serial Data Output (Q) is at high impedance.

Unless an internal Program, Erase or Write Status Register

cycle is in progress, the device will be in the Standby mode

(this is not the Deep Power-down mode). Driving Chip Select

A25L40P Series

( S ) Low enables the device, placing it in the active power

mode.

After Power-up, a falling edge on Chip Select ( S ) is required

prior to the start of any instruction.

Hold (HOLD ). The Hold ( HOLD ) signal is used to pause

any serial communications with the device without

deselecting the device.

During the Hold condition, the Serial Data Output (Q) is high

impedance, and Serial Data Input (D) and Serial Clock (C)

are Don’t Care. To start the Hold condition, the device must

be selected, with Chip Select ( S ) driven Low.

Write Protect ( W ). The main purpose of this input signal is

to freeze the size of the area of memory that is protected

against program or erase instructions (as specified by the

values in the BP2, BP1 and BP0 bits of the Status Register).

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 2,

is the clock polarity when the bus master 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)

PRELIMINARY (May, 2007, Version 0.4)

3

AMIC Technology Corp.

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