ATMEL ATA5570, AT25DF081 Datasheet

Features

• Single 1.65V - 1.95V Supply

• Serial Peripheral Interface (SPI) Compatible

– Supports SPI Modes 0 and 3

• 66 MHz Maximum Clock Frequency

• Flexible, Uniform Erase Architecture

– 4-Kbyte Blocks – 32-Kbyte Blocks – 64-Kbyte Blocks – Full Chip Erase

• Individual Sector Protection with Global Protect/Unprotect Feature

– Sixteen 64-Kbyte Physical Sectors

• Hardware Controlled Locking of Protected Sectors

• Flexible Programming

– Byte/Page Program (1 to 256 Bytes)

• Automatic Checking and Reporting of Erase/Program Failures

• JEDEC Standard Manufacturer and Device ID Read Methodology

• Low Power Dissipation

– 7 mA Active Read Current (Typical) – 8 µA Deep Power-Down Current (Typical)

• Endurance: 100,000 Program/Erase Cycles

• Data Retention: 20 Years

• Complies with Full Industrial Temperature Range

• Industry Standard Green (Pb/Halide-free/RoHS Compliant) Package Options

– 8-lead SOIC (150-mil wide) – 8-contact Ultra Thin DFN (5 mm x 6 mm x 0.6 mm) – 11-ball dBGA (WLCSP)

8-megabit

1.65-volt Minimum SPI Serial Flash Memory

AT25DF081

1. Description

The AT25DF081 is a serial interface Flash memory device designed for use in a wide variety of high-volume consumer based applications in which program code is shadowed from Flash memory into embedded or external RAM for execution. The flexible erase architecture of the AT25DF081, with its erase granularity as small as 4-Kbytes, makes it ideal for data storage as well, eliminating the need for additional data storage EEPROM devices.

The physical sectoring and the erase block sizes of the AT25DF081 have been optimized to meet the needs of today's code and data storage applications. By optimizing the size of the physical sectors and erase blocks, the memory space can be used much more efficiently. Because certain code modules and data storage segments must reside by themselves in their own protected sectors, the wasted and unused memory space that occurs with large sectored and large block erase Flash memory devices can be greatly reduced. This increased memory space efficiency allows additional code routines and data storage segments to be added while still maintaining the same overall device density.

3674E–DFLASH–8/08

The AT25DF081 also offers a sophisticated method for protecting individual sectors against erroneous or malicious program and erase operations. By providing the ability to individually protect and unprotect sectors, a system can unprotect a specific sector to modify its contents while keeping the remaining sectors of the memory array securely protected. This is useful in applications where program code is patched or updated on a subroutine or module basis, or in applications where data storage segments need to be modified without running the risk of errant modifications to the program code segments. In addition to individual sector protection capabilities, the AT25DF081 incorporates Global Protect and Global Unprotect features that allow the entire memory array to be either protected or unprotected all at once. This reduces overhead during the manufacturing process since sectors do not have to be unprotected one-by-one prior to initial programming.

Specifically designed for use in 1.8-volt systems, the AT25DF081 supports read, program, and erase operations with a supply voltage range of 1.65V to 1.95V. No separate voltage is required for programming and erasing.

AT25DF081

3674E–DFLASH–8/08

2. Pin Descriptions and Pinouts

Table 2-1. Pin Descriptions

Symbol Name and Function

CHIP SELECT: Asserting the CS pin selects the device. When the CS pin is deasserted, the

device will be deselected and normally be placed in standby mode (not Deep Power-Down mode), and the SO pin will be in a high-impedance state. When the device is deselected, data will not be

SCK

accepted on the SI pin. A high-to-low transition on the CS

is required to end an operation. When ending an internally self-timed operation such as a program or erase cycle, the device will not enter the standby mode until the completion of the operation.

SERIAL CLOCK: This pin is used to provide a clock to the device and is used to control the flow of data to and from the device. Command, address, and input data present on the SI pin is always latched on the rising edge of SCK, while output data on the SO pin is always clocked out on the falling edge of SCK.

SERIAL INPUT: The SI pin is used to shift data into the device. The SI pin is used for all data input including command and address sequences. Data on the SI pin is always latched on the rising edge of SCK.

SERIAL OUTPUT: The SO pin is used to shift data out from the device. Data on the SO pin is always clocked out on the falling edge of SCK.

pin is required to start an operation, and a low-to-high transition

AT25DF081

Asserted

State Type

Low Input

Input

Output

HOLD

GND

WRITE PROTECT: The WP pin controls the hardware locking feature of the device. Please refer to

“Protection Commands and Features” on page 12 for more details on protection features and the

WP pin. The WP

not be used. However, it is recommended that the WP pin also be externally connected to VCC whenever possible.

HOLD: The HOLD pin is used to temporarily pause serial communication without deselecting or resetting the device. While the HOLD pin is asserted, transitions on the SCK pin and data on the SI pin will be ignored, and the SO pin will be in a high-impedance state.

The CS condition to start. A Hold condition pauses serial communication only and does not have an effect on internally self-timed operations such as a program or erase cycle. Please refer to “Hold” on

page 27 for additional details on the Hold operation.

The HOLD However, it is recommended that the HOLD pin also be externally connected to VCC whenever possible.

DEVICE POWER SUPPLY: The VCC pin is used to supply the source voltage to the device. Operations at invalid V

GROUND: The ground reference for the power supply. GND should be connected to the system ground.

pin is internally pulled-high and may be left floating if hardware controlled protection will

pin must be asserted, and the SCK pin must be in the low state in order for a Hold

pin is internally pulled-high and may be left floating if the Hold function will not be used.

voltages may produce spurious results and should not be attempted.

Low Input

Power

3674E–DFLASH–8/08

Figure 2-1. 8-SOIC Top View Figure 2-2. 8-UDFN Top View Figure 2-3. 11-dBGA (Top View

1 2 3 4

8 7 6 5

CS SO

GND

VCC HOLD SCK SI

234

VCC

HOLD

SCK

GND

FLASH

MEMORY

ARRAY

Y-GATING

SCK

Y-DECODER

ADDRESS LATCH

X-DECODER

I/O BUFFERS

AND LATCHES

CONTROL AND

PROTECTION LOGIC

SRAM

DATA BUFFER

INTERFACE

CONTROL

AND

LOGIC

HOLD

CS SO

GND

VCC HOLD SCK SI

Through Back of Die)

3. Block Diagram

4. Memory Array

AT25DF081

To provide the greatest flexibility, the memory array of the AT25DF081 can be erased in four levels of granularity including a full chip erase. In addition, the array has been divided into physical sectors of uniform size, of which each sector can be individually protected from program and erase operations. The size of the physical sectors is optimized for both code and data storage applications, allowing both code and data segments to reside in their own isolated regions. Figure 4-1 on page 5 illustrates the breakdown of each erase level as well as the breakdown of each physical sector.

3674E–DFLASH–8/08

Figure 4-1. Memory Architecture Diagram

64KB

• • •

64KB

32KB

• • •

64KB

(Sector 15)

32KB

64KB

(Sector 0)

32KB

• • •

64KB

(Sector 14)

Block Erase Detail

AT25DF081

Page Program Detail

Internal Sectoring for 64KB 32KB 4KB 1-256 Byte

Sector Protection Block Erase Block Erase Block Erase Page Program

Function (D8h Command) (52h Command) (20h Command) (02h Command)

4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB

4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB 4KB

Range

0FFFFFh– 0FF000h 0FEFFFh– 0FE000h 0FDFFFh – 0FD000h 0FCFFFh– 0FC000h 0FBFFFh– 0FB000h 0FAFFFh– 0FA000h 0F9FFFh – 0F9000h 0F8FFFh – 0F8000h 0F7FFFh – 0F7000h 0F6FFFh – 0F6000h 0F5FFFh – 0F5000h 0F4FFFh – 0F4000h 0F3FFFh – 0F3000h 0F2FFFh – 0F2000h 0F1FFFh – 0F1000h 0F0FFFh – 0F0000h 0EFFFFh–0EF000h 0EEFFFh– 0EE000h 0EDFFFh – 0ED000h 0ECFFFh– 0EC000h 0EBFFFh– 0EB000h 0EAFFFh– 0EA000h 0E9FFFh– 0E9000h 0E8FFFh– 0E8000h 0E7FFFh– 0E7000h 0E6FFFh– 0E6000h 0E5FFFh– 0E5000h 0E4FFFh– 0E4000h 0E3FFFh– 0E3000h 0E2FFFh– 0E2000h 0E1FFFh– 0E1000h 0E0FFFh– 0E0000h

00FFFFh – 00F000h 00EFFFh– 00E000h 00DFFFh – 00D000h 00CFFFh – 00C000h 00BFFFh– 00B000h 00AFFFh –00A000h 009FFFh –009000h 008FFFh –008000h 007FFFh –007000h 006FFFh –006000h 005FFFh –005000h 004FFFh –004000h 003FFFh –003000h 002FFFh –002000h 001FFFh –001000h 000FFFh –000000h

256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes 256 Bytes

Page AddressBlock Address

Range

0FFFFFh– 0FFF00h 0FFEFFh–0FFE00h 0FFDFFh– 0FFD00h 0FFCFFh– 0FFC00h 0FFBFFh– 0FFB00h 0FFAFFh – 0FFA00h 0FF9FFh– 0FF900h 0FF8FFh– 0FF800h 0FF7FFh– 0FF700h 0FF6FFh– 0FF600h 0FF5FFh– 0FF500h 0FF4FFh– 0FF400h 0FF3FFh– 0FF300h 0FF2FFh– 0FF200h 0FF1FFh– 0FF100h 0FF0FFh– 0FF000h 0FEFFFh– 0FEF00h 0FEEFFh– 0FEE00h 0FEDFFh– 0FED00h 0FECFFh– 0FEC00h 0FEBFFh– 0FEB00h 0FEAFFh– 0FEA00h 0FE9FFh– 0FE900h 0FE8FFh– 0FE800h

0017FFh – 001700h 0016FFh – 001600h 0015FFh – 001500h 0014FFh – 001400h 0013FFh – 001300h 0012FFh – 001200h 0011FFh – 001100h 0010FFh – 001000h 000FFFh –000F00h 000EFFh – 000E00h 000DFFh – 000D00h 000CFFh – 000C00h 000BFFh – 000B00h 000AFFh – 000A00h 0009FFh – 000900h 0008FFh – 000800h 0007FFh – 000700h 0006FFh – 000600h 0005FFh – 000500h 0004FFh – 000400h 0003FFh – 000300h 0002FFh – 000200h 0001FFh – 000100h 0000FFh – 000000h

3674E–DFLASH–8/08

5. Device Operation

SCK

MSB LSB

MSB

LSB

The AT25DF081 is controlled by a set of instructions that are sent from a host controller, commonly referred to as the SPI Master. The SPI Master communicates with the AT25DF081 via the SPI bus which is comprised of four signal lines: Chip Select (CS Input (SI), and Serial Output (SO).

The SPI protocol defines a total of four modes of operation (mode 0, 1, 2, or 3) with each mode differing in respect to the SCK polarity and phase and how the polarity and phase control the flow of data on the SPI bus. The AT25DF081 supports the two most common modes, SPI Modes 0 and 3. The only difference between SPI Modes 0 and 3 is the polarity of the SCK signal when in the inactive state (when the SPI Master is in standby mode and not transferring any data). With SPI Modes 0 and 3, data is always latched in on the rising edge of SCK and always output on the falling edge of SCK.

Figure 5-1. SPI Mode 0 and 3

), Serial Clock (SCK), Serial

6. Commands and Addressing

A valid instruction or operation must always be started by first asserting the CS pin. After the CS pin has been asserted, the SPI Master must then clock out a valid 8-bit opcode on the SPI bus. Following the opcode, instruction dependent information such as address and data bytes would then be clocked out by the SPI Master. All opcode, address, and data bytes are transferred with the most significant bit (MSB) first. An operation is ended by deasserting the CS

Opcodes not supported by the AT25DF081 will be ignored by the device and no operation will be started. The device will continue to ignore any data presented on the SI pin until the start of the next operation (CS serted before complete opcode and address information is sent to the device, then no operation will be performed and the device will simply return to the idle state and wait for the next operation.

Addressing of the device requires a total of three bytes of information to be sent, representing address bits A23-A0. Since the upper address limit of the AT25DF081 memory array is 0FFFFFh, address bits A23-A20 are always ignored by the device.

pin.

pin being deasserted and then reasserted). In addition, if the CS pin is deas-

AT25DF081

3674E–DFLASH–8/08

AT25DF081

Table 6-1. Command Listing

Command Opcode Address Bytes Dummy Bytes Data Bytes

Read Commands

Read Array 0Bh 0000 1011 3 1 1+

Read Array (Low Frequency) 03h 0000 0011 3 0 1+

Program and Erase Commands

Block Erase (4-KBytes) 20h 0010 0000 3 0 0

Block Erase (32-KBytes) 52h 0101 0010 3 0 0

Block Erase (64-KBytes) D8h 1101 1000 3 0 0

Chip Erase

Byte/Page Program (1 to 256 Bytes) 02h 0000 0010 3 0 1+

Protection Commands

Write Enable 06h 0000 0110 0 0 0

Write Disable 04h 0000 0100 0 0 0

Protect Sector 36h 0011 0110 3 0 0

Unprotect Sector 39h 0011 1001 3 0 0

60h 0110 0000 0 0 0

C7h 1100 0111 0 0 0

Global Protect/Unprotect Use Write Status Register command

Read Sector Protection Registers 3Ch 0011 1100 3 0 1+

Status Register Commands

Read Status Register 05h 0000 0101 0 0 1+

Write Status Register 01h 0000 0001 0 0 1

Miscellaneous Commands

Read Manufacturer and Device ID 9Fh 1001 1111 0 0 1 to 4

Deep Power-Down B9h 1011 1001 0 0 0

Resume from Deep Power-Down ABh 1010 1011 0 0 0

3674E–DFLASH–8/08

7. Read Commands

SCK

MSB MSB

2310

00001011

675410119812 394243414037 3833 36353431 3229 30 44 47 484645

OPCODE

AAAA AAAA A

MSB

XXXXXXXX

MSB MSB

DDDDDDDDDD

ADDRESS BITS A23-A0 DON'T CARE

DATA BYTE 1

HIGH-IMPEDANCE

SCK

MSB MSB

2310

00000011

675410119812 373833 36353431 3229 30 39 40

OPCODE

AAAA AAAA A

MSB MSB

DDDDDDDDDD

ADDRESS BITS A23-A0

DATA BYTE 1

HIGH-IMPEDANCE

7.1 Read Array

The Read Array command can be used to sequentially read a continuous stream of data from the device by simply providing the SCK signal once the initial starting address has been specified. The device incorporates an internal address counter that automatically increments on every clock cycle.

Two opcodes, 0Bh and 03h, can be used for the Read Array command. The use of each opcode depends on the maximum SCK frequency that will be used to read data from the device. The 0Bh opcode can be used at any SCK frequency up to the maximum specified by f opcode can be used for lower frequency read operations up to the maximum specified by f

To perform the Read Array operation, the CS opcode (0Bh or 03h) must be clocked into the device. After the opcode has been clocked in, the three address bytes must be clocked in to specify the starting address location of the first byte to read within the memory array. If the 0Bh opcode is used, then one don’t care byte must also be clocked in after the three address bytes.

After the three address bytes (and the one don’t care byte if using opcode 0Bh) have been clocked in, additional clock cycles will result in serial data being output on the SO pin. The data is always output with the MSB of a byte first. When the last byte (0FFFFFh) of the memory array has been read, the device will continue reading back at the beginning of the array (000000h). No delays will be incurred when wrapping around from the end of the array to the beginning of the array.

. The 03h

SCK

RDLF

pin must first be asserted and the appropriate

Deasserting the CS ance state. The CS data be read.

Figure 7-1. Read Array – 0Bh Opcode

Figure 7-2. Read Array – 03h Opcode

pin will terminate the read operation and put the SO pin into a high-imped pin can be deasserted at any time and does not require that a full byte of

AT25DF081

3674E–DFLASH–8/08

8. Program and Erase Commands

8.1 Byte/Page Program

The Byte/Page Program command allows anywhere from a single byte of data to 256 bytes of data to be programmed into previously erased memory locations. An erased memory location is one that has all eight bits set to the logical “1” state (a byte value of FFh). Before a Byte/Page Program command can be started, the Write Enable command must have been previously issued to the device (see Write Enable command description) to set the Write Enable Latch (WEL) bit of the Status Register to a logical “1” state.

To perform a Byte/Page Program command, an opcode of 02h must be clocked into the device followed by the three address bytes denoting the first byte location of the memory array to begin programming at. After the address bytes have been clocked in, data can then be clocked into the device and will be stored in an internal buffer.

If the starting memory address denoted by A23-A0 does not fall on an even 256-byte page boundary (A7-A0 are not all 0), then special circumstances regarding which memory locations will be programmed will apply. In this situation, any data that is sent to the device that goes beyond the end of the page will wrap around back to the beginning of the same page. For example, if the starting address denoted by A23-A0 is 0000FEh, and three bytes of data are sent to the device, then the first two bytes of data will be programmed at addresses 0000FEh and 0000FFh while the last byte of data will be programmed at address 000000h. The remaining bytes in the page (addresses 000001h through 0000FDh) will be unaffected and will not change. In addition, if more than 256 bytes of data are sent to the device, then only the last 256 bytes sent will be latched into the internal buffer.

AT25DF081

When the CS gram it into the appropriate memory array locations based on the starting address specified by A23-A0 and the number of complete data bytes sent to the device. If less than 256 bytes of data were sent to the device, then the remaining bytes within the page will not be altered. The programming of the data bytes is internally self-timed and should take place in a time of t

The three address bytes and at least one complete byte of data must be clocked into the device before the CS (multiples of eight bits); otherwise, the device will abort the operation and no data will be programmed into the memory array. In addition, if the address specified by A23-A0 points to a memory location within a sector that is in the protected state (see “Protect Sector” on page 13), then the Byte/Page Program command will not be executed, and the device will return to the idle state once the CS back to the logical “0” state if the program cycle aborts due to an incomplete address being sent, an incomplete byte of data being sent, or because the memory location to be programmed is protected.

While the device is programming, the Status Register can be read and will indicate that the device is busy. For faster throughput, it is recommended that the Status Register be polled rather than waiting the t some point before the program cycle completes, the WEL bit in the Status Register will be reset back to the logical “0” state.

The device also incorporates an intelligent programming algorithm that can detect when a byte location fails to program properly. If a programming error arises, it will be indicated by the EPE bit in the Status Register.

pin is deasserted, the device will take the data stored in the internal buffer and pro-

pin is deasserted, and the CS pin must be deasserted on even byte boundaries

pin has been deasserted. The WEL bit in the Status Register will be reset

time to determine if the data bytes have finished programming. At

3674E–DFLASH–8/08

Figure 8-1. Byte Program

SCK

MSB MSB

2310

00000010

6754983937 3833 36353431 3229 30

OPCODE

HIGH-IMPEDANCE

AA AAAA

MSB

DDDDDDDD

ADDRESS BITS A23-A0 DATA IN BYTE 1

MSB

DDDDDDDD

DATA IN BYTE n

SCK

Figure 8-2. Page Program

2310

OPCODE

00000010

MSB MSB

HIGH-IMPEDANCE

675410119812 3937 3833 36353431 3229 30

ADDRESS BITS A23-A0 DATA IN

AAAA AAAA A

DDDDDDDD

MSB

8.2 Block Erase

A block of 4K-, 32K-, or 64K-bytes can be erased (all bits set to the logical “1” state) in a single operation by using one of three different opcodes for the Block Erase command. An opcode of 20h is used for a 4K-byte erase, an opcode of 52h is used for a 32K-byte erase, and an opcode of D8h is used for a 64K-byte erase. Before a Block Erase command can be started, the Write Enable command must have been previously issued to the device to set the WEL bit of the Status Register to a logical “1” state.

To perform a Block Erase, the CS

pin must first be asserted and the appropriate opcode (20h, 52h, or D8h) must be clocked into the device. After the opcode has been clocked in, the three address bytes specifying an address within the 4K-, 32K-, or 64K-byte block to be erased must be clocked in. Any additional data clocked into the device will be ignored. When the CS deasserted, the device will erase the appropriate block. The erasing of the block is internally self-timed and should take place in a time of t

BLKE

Since the Block Erase command erases a region of bytes, the lower order address bits do not need to be decoded by the device. Therefore, for a 4K-byte erase, address bits A11-A0 will be ignored by the device and their values can be either a logical “1” or “0”. For a 32K-byte erase, address bits A14-A0 will be ignored, and for a 64K-byte erase, address bits A15-A0 will be ignored by the device. Despite the lower order address bits not being decoded by the device, the complete three address bytes must still be clocked into the device before the CS serted, and the CS otherwise, the device will abort the operation and no erase operation will be performed.

pin must be deasserted on an even byte boundary (multiples of eight bits);

pin is deas-

pin is

AT25DF081

3674E–DFLASH–8/08

AT25DF081

If the address specified by A23-A0 points to a memory location within a sector that is in the protected state, then the Block Erase command will not be executed, and the device will return to the idle state once the CS

The WEL bit in the Status Register will be reset back to the logical “0” state if the erase cycle aborts due to an incomplete address being sent or because a memory location within the region to be erased is protected.

While the device is executing a successful erase cycle, the Status Register can be read and will indicate that the device is busy. For faster throughput, it is recommended that the Status Register be polled rather than waiting the t some point before the erase cycle completes, the WEL bit in the Status Register will be reset back to the logical “0” state.

The device also incorporates an intelligent erasing algorithm that can detect when a byte location fails to erase properly. If an erase error arises, it will be indicated by the EPE bit in the Status Register.

Figure 8-3. Block Erase

pin has been deasserted.

time to determine if the device has finished erasing. At

BLKE

8.3 Chip Erase

2310

675410119812 3129 3027 2826

SCK

OPCODE

CCCCCCCC

MSB MSB

HIGH-IMPEDANCE

AAAA AAAA A A A A

ADDRESS BITS A23-A0

The entire memory array can be erased in a single operation by using the Chip Erase command. Before a Chip Erase command can be started, the Write Enable command must have been previously issued to the device to set the WEL bit of the Status Register to a logical “1” state.

Two opcodes, 60h and C7h, can be used for the Chip Erase command. There is no difference in device functionality when utilizing the two opcodes, so they can be used interchangeably. To perform a Chip Erase, one of the two opcodes (60h or C7h) must be clocked into the device. Since the entire memory array is to be erased, no address bytes need to be clocked into the device, and any data clocked in after the opcode will be ignored. When the CS

pin is deasserted, the device will erase the entire memory array. The erasing of the device is internally self-timed and should take place in a time of t

The complete opcode must be clocked into the device before the CS CS

pin must be deasserted on an even byte boundary (multiples of eight bits); otherwise, no

CHPE

pin is deasserted, and the

erase will be performed. In addition, if any sector of the memory array is in the protected state, then the Chip Erase command will not be executed, and the device will return to the idle state once the CS

pin has been deasserted. The WEL bit in the Status Register will be reset back to

the logical “0” state if a sector is in the protected state.

3674E–DFLASH–8/08

While the device is executing a successful erase cycle, the Status Register can be read and will indicate that the device is busy. For faster throughput, it is recommended that the Status Regis-

ter be polled rather than waiting the t

SCK

MSB

2310

00000110

6754

OPCODE

HIGH-IMPEDANCE

time to determine if the device has finished erasing. At

CHPE

some point before the erase cycle completes, the WEL bit in the Status Register will be reset back to the logical “0” state.

Figure 8-4. Chip Erase

SCK

9. Protection Commands and Features

9.1 Write Enable

The Write Enable command is used to set the Write Enable Latch (WEL) bit in the Status Register to a logical “1” state. The WEL bit must be set before a program, erase, Protect Sector, Unprotect Sector, or Write Status Register command can be executed. This makes the issuance of these commands a two step process, thereby reducing the chances of a command being accidentally or erroneously executed. If the WEL bit in the Status Register is not set prior to the issuance of one of these commands, then the command will not be executed.

To issue the Write Enable command, the CS must be clocked into the device. No address bytes need to be clocked into the device, and any data clocked in after the opcode will be ignored. When the CS the Status Register will be set to a logical “1”. The complete opcode must be clocked into the device before the CS boundary (multiples of eight bits); otherwise, the device will abort the operation and the state of the WEL bit will not change.

pin is deasserted, and the CS pin must be deasserted on an even byte

2310

OPCODE

CCCCCCCC

MSB

HIGH-IMPEDANCE

6754

pin must first be asserted and the opcode of 06h

pin is deasserted, the WEL bit in

AT25DF081

Figure 9-1. Write Enable

3674E–DFLASH–8/08

+ 26 hidden pages