20005045-25VF080B-C-DS.fm

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DS20005045C-page 1

Features

• Single Voltage Read and Write Operations

- 2.7-3.6V

• Serial Interface Architecture

- SPI Compatible: Mode 0 and Mode 3

• High Speed Clock Frequency

- 50/66 MHz conditional (see 

Table 5-6

)

• Superior Reliability

- Endurance: 100,000 Cycles (typical)
- Greater than 100 years Data Retention

• Low Power Consumption:

- Active Read Current: 10 mA (typical)
- Standby Current: 5 µA (typical)

• Flexible Erase Capability

- Uniform 4 KByte sectors
- Uniform 32 KByte overlay blocks
- Uniform 64 KByte overlay blocks

• Fast Erase and Byte-Program:

- Chip-Erase Time: 35 ms (typical)
- Sector-/Block-Erase Time: 18 ms (typical)
- Byte-Program Time: 7 µs (typical)

• Auto Address Increment (AAI) Programming

- Decrease total chip programming time over 

Byte-Program operations

• End-of-Write Detection

- Software polling the BUSY bit in Status Register
- Busy Status readout on SO pin in AAI Mode

• Hold Pin (HOLD#)

- Suspends a serial sequence to the memory

without deselecting the device

• Write Protection (WP#)

- Enables/Disables the Lock-Down function of the 

status register

• Software Write Protection

- Write protection through Block-Protection bits in 

status register

• Temperature Range

- Commercial: 0°C to +70°C
- Industrial: -40°C to +85°C

• Packages Available

- 8-lead SOIC (200 mils)
- 8-contact WSON (6mm x 5mm)
- 8-lead PDIP (300 mils)

• All devices are RoHS compliant

Product Description

25 series Serial Flash family features a four-wire, SPI-
compatible interface that allows for a low pin-count
package which occupies less board space and ulti-
mately lowers total system costs. The SST25VF080B
devices are enhanced with improved operating fre-
quency and lower power consumption. SST25VF080B
SPI serial flash memories are manufactured with pro-
prietary, high-performance CMOS SuperFlash technol-
ogy. The split-gate cell design and thick-oxide tunneling
injector attain better reliability and manufacturability
compared with alternate approaches.

The SST25VF080B devices significantly improve per-
formance and reliability, while lowering power con-
sumption. The devices write (Program or Erase) with a
single power supply of 2.7-3.6V for SST25VF080B.
The total energy consumed is a function of the applied
voltage, current, and time of application. Since for any
given voltage range, the SuperFlash technology uses
less current to program and has a shorter erase time,
the total energy consumed during any Erase or Pro-
gram operation is less than alternative flash memory
technologies. 

The SST25VF080B device is offered in 8-lead SOIC
(200 mils), 8-contact WSON (6mm x 5mm), and 8-lead
PDIP (300 mils) packages. See 

Figure 2-1

 for pin

assignments.

SST25VF080B

8 Mbit SPI Serial Flash

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SST25VF080B

DS20005045C-page 2

 

 2015 Microchip Technology Inc.

1.0

BLOCK DIAGRAM

FIGURE 1-1:

FUNCTIONAL BLOCK DIAGRAM

1296 B1.0

I/O Buffers

and

Data Latches

SuperFlash

Memory

X - Decoder

Control Logic

Address

Buffers

and

Latches

CE#

Y - Decoder

SCK

SI

SO

WP#

HOLD#

Serial Interface

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DS20005045C-page 3

SST25VF080B

2.0

PIN DESCRIPTION

FIGURE 2-1:

PIN ASSIGNMENTS

TABLE 2-1:

PIN DESCRIPTION

Symbol

Pin Name

Functions

SCK

Serial Clock

To provide the timing of the serial interface.
Commands, addresses, or input data are latched on the rising edge of the clock 
input, while output data is shifted out on the falling edge of the clock input.

SI

Serial Data Input

To transfer commands, addresses, or data serially into the device.
Inputs are latched on the rising edge of the serial clock.

SO

Serial Data Output

To transfer data serially out of the device.
Data is shifted out on the falling edge of the serial clock.
Outputs Flash busy status during AAI Programming when reconfigured as RY/BY# 
pin. See 

“Hardware End-of-Write Detection” on page 10

 for details.

CE#

Chip Enable

The device is enabled by a high to low transition on CE#. CE# must remain low for 
the duration of any command sequence.

WP#

Write Protect

The Write Protect (WP#) pin is used to enable/disable BPL bit in the status register.

HOLD#

Hold

To temporarily stop serial communication with SPI flash memory without resetting 
the device.

V

DD

Power Supply

To provide power supply voltage: 2.7-3.6V for SST25VF080B

V

SS

Ground

1

2

3

4

8

7

6

5

CE#

SO

WP#

VSS

VDD 

HOLD#

SCK

SI

Top View

1296 08-soic S2A P1.0

1

2

3

4

8

7

6

5

CE#

SO

WP#

VSS

Top View

VDD

HOLD#

SCK

SI

1296 08-wson QA P2.0

8-lead SOIC

8-contact WSON

CE#

SO

WP#

VSS

VDD 

HOLD#

SCK

SI

Top View

1296 08-pdip-PA-P3.0

8-lead PDIP

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SST25VF080B

DS20005045C-page 4

 

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3.0

MEMORY ORGANIZATION

The SST25VF080B SuperFlash memory array is orga-
nized in uniform 4 KByte erasable sectors with 32
KByte overlay blocks and 64 KByte overlay erasable
blocks.

4.0

DEVICE OPERATION

The SST25VF080B is accessed through the SPI (Serial
Peripheral Interface) bus compatible protocol. The SPI
bus consist of four control lines; Chip Enable (CE#) is

used to select the device, and data is accessed through
the Serial Data Input (SI), Serial Data Output (SO), and
Serial Clock (SCK).

The SST25VF080B supports both Mode 0 (0,0) and
Mode 3 (1,1) of SPI bus operations. The difference
between the two modes, as shown in 

Figure 4-1

, is the

state of the SCK signal when the bus master is in
Stand-by mode and no data is being transferred. The
SCK signal is low for Mode 0 and SCK signal is high for
Mode 3. For both modes, the Serial Data In (SI) is sam-
pled at the rising edge of the SCK clock signal and the
Serial Data Output (SO) is driven after the falling edge
of the SCK clock signal.

FIGURE 4-1:

SPI PROTOCOL

4.1

Hold Operation

The HOLD# pin is used to pause a serial sequence
underway with the SPI flash memory without resetting
the clocking sequence. To activate the HOLD# mode,
CE# must be in active low state. The HOLD# mode
begins when the SCK active low state coincides with
the falling edge of the HOLD# signal. The HOLD mode
ends when the HOLD# signal’s rising edge coincides
with the SCK active low state.

If the falling edge of the HOLD# signal does not coin-
cide with the SCK active low state, then the device
enters Hold mode when the SCK next reaches the
active low state. Similarly, if the rising edge of the

HOLD# signal does not coincide with the SCK active
low state, then the device exits in Hold mode when the
SCK next reaches the active low state. See 

Figure 4-2

for Hold Condition waveform.

Once the device enters Hold mode, SO will be in high-
impedance state while SI and SCK can be V

IL

 or V

IH.

If CE# is driven active high during a Hold condition, it
resets the internal logic of the device. As long as
HOLD# signal is low, the memory remains in the Hold
condition. To resume communication with the device,
HOLD# must be driven active high, and CE# must be
driven active low. See 

Figure 5-3

 for Hold timing.

FIGURE 4-2:

HOLD CONDITION WAVEFORM

1296 SPIprot.0

MODE 3

SCK

SI

SO

CE#

MODE 3

DON'T CARE

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

MODE 0

MODE 0

HIGH IMPEDANCE

MSB

MSB

Active

Hold

Active

Hold

Active

1296 HoldCond.0

SCK

HOLD#

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DS20005045C-page 5

SST25VF080B

4.2

Write Protection

SST25VF080B provides software Write protection. The
Write Protect pin (WP#) enables or disables the lock-
down function of the status register. The Block-Protec-
tion bits (BP3, BP2, BP1, BP0, and BPL) in the status
register provide Write protection to the memory array
and the status register. See 

Table 4-3

 for the Block-Pro-

tection description.

4.2.1

WRITE PROTECT PIN (WP#)

The Write Protect (WP#) pin enables the lock-down
function of the BPL bit (bit 7) in the status register.
When WP# is driven low, the execution of the Write-
Status-Register (WRSR) instruction is determined by
the value of the BPL bit (see 

Table 4-1

). When WP# is

high, the lock-down function of the BPL bit is disabled.

4.3

Status Register

The software status register provides status on
whether the flash memory array is available for any
Read or Write operation, whether the device is Write
enabled, and the state of the Memory Write protection.

During an internal Erase or Program operation, the sta-
tus register may be read only to determine the comple-
tion of an operation in progress. 

Table 4-2

 describes

the function of each bit in the software status register.

4.3.1

BUSY

The Busy bit determines whether there is an internal
Erase or Program operation in progress. A “1” for the
Busy bit indicates the device is busy with an operation
in progress. A “0” indicates the device is ready for the
next valid operation.

4.3.2

WRITE ENABLE LATCH (WEL)

The Write-Enable-Latch bit indicates the status of the
internal memory Write Enable Latch. If the Write-
Enable-Latch bit is set to “1”, it indicates the device is
Write enabled. If the bit is set to “0” (reset), it indicates
the device is not Write enabled and does not accept

any memory Write (Program/Erase) commands. The
Write-Enable-Latch bit is automatically reset under the
following conditions:

• Power-up

• Write-Disable (WRDI) instruction completion

• Byte-Program instruction completion

• Auto Address Increment (AAI) programming is 

completed or reached its highest unprotected 
memory address

• Sector-Erase instruction completion

• Block-Erase instruction completion

• Chip-Erase instruction completion

• Write-Status-Register instructions

TABLE 4-1:

CONDITIONS TO EXECUTE WRITE-STATUS-REGISTER (WRSR) INSTRUCTION

WP#

BPL

Execute WRSR Instruction

L

1

Not Allowed

L

0

Allowed

H

X

Allowed

TABLE 4-2:

SOFTWARE STATUS REGISTER

Bit

Name

Function

Default at

Power-up

Read/Write

0

BUSY

1 = Internal Write operation is in progress
0 = No internal Write operation is in progress

0

R

1

WEL

1 = Device is memory Write enabled
0 = Device is not memory Write enabled

0

R

2

BP0

Indicate current level of block write protection (See 

Table 4-3

)

1

R/W

3

BP1

Indicate current level of block write protection (See 

Table 4-3

)

1

R/W

4

BP2

Indicate current level of block write protection (See 

Table 4-3

)

1

R/W

5

BP3

Indicate current level of block write protection (See 

Table 4-3

)

0

R/W

6

AAI

Auto Address Increment Programming status
1 = AAI programming mode
0 = Byte-Program mode

0

R

7

BPL

1 = BP3, BP2, BP1, BP0 are read-only bits
0 = BP3, BP2, BP1, BP0 are read/writable

0

R/W

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DS20005045C-page 6

 

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4.3.3

AUTO ADDRESS INCREMENT (AAI)

The Auto Address Increment Programming-Status bit
provides status on whether the device is in AAI pro-
gramming mode or Byte-Program mode. The default at
power up is Byte-Program mode.

4.3.4

BLOCK PROTECTION (BP3,BP2, 
BP1, BP0)

The Block-Protection (BP3, BP2, BP1, BP0) bits define
the size of the memory area, as defined in 

Table 4-3

, to

be software protected against any memory Write (Pro-
gram or Erase) operation. The Write-Status-Register
(WRSR) instruction is used to program the BP3, BP2,

BP1 and BP0 bits as long as WP# is high or the Block-
Protect-Lock (BPL) bit is 0. Chip-Erase can only be
executed if Block-Protection bits are all 0. After power-
up, BP3, BP2, BP1 and BP0 are set to 1.

4.3.5

BLOCK PROTECTION LOCK-DOWN 
(BPL)

WP# pin driven low (V

IL

), enables the Block-Protection-

Lock-Down (BPL) bit. When BPL is set to 1, it prevents
any further alteration of the BPL, BP3, BP2, BP1, and
BP0 bits. When the WP# pin is driven high (V

IH

), the

BPL bit has no effect and its value is “Don’t Care”. After
power-up, the BPL bit is reset to 0.

TABLE 4-3:

SOFTWARE STATUS REGISTER BLOCK PROTECTION FOR

 

SST25VF080B

1

1. X = Don’t Care (RESERVED) default is “0

Protection Level

Status Register Bit

2

2. Default at power-up for BP2, BP1, and BP0 is ‘111’. (All Blocks Protected)

Protected Memory Address

BP3

BP2

BP1

BP0

8 Mbit

None

X

0

0

0

None

Upper 1/16

X

0

0

1

F0000H-FFFFFH

Upper 1/8

X

0

1

0

E0000H-FFFFFH

Upper 1/4

X

0

1

1

C0000H-FFFFFH

Upper 1/2

X

1

0

0

80000H-FFFFFH

All Blocks

X

1

0

1

00000H-FFFFFH

All Blocks

X

1

1

0

00000H-FFFFFH

All Blocks

X

1

1

1

00000H-FFFFFH

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DS20005045C-page 7

SST25VF080B

4.4

Instructions

Instructions are used to read, write (Erase and Pro-
gram), and configure the SST25VF080B. The instruc-
tion bus cycles are 8 bits each for commands (Op
Code), data, and addresses. Prior to executing any
Byte-Program, Auto Address Increment (AAI) program-
ming, Sector-Erase, Block-Erase, Write-Status-Regis-
ter, or Chip-Erase instructions, the Write-Enable
(WREN) instruction must be executed first. The com-
plete list of instructions is provided in 

Table 4-4

. All

instructions are synchronized off a high to low transition

of CE#. Inputs will be accepted on the rising edge of
SCK starting with the most significant bit. CE# must be
driven low before an instruction is entered and must be
driven high after the last bit of the instruction has been
shifted in (except for Read, Read-ID, and Read-Status-
Register instructions). Any low to high transition on
CE#, before receiving the last bit of an instruction bus
cycle, will terminate the instruction in progress and
return the device to standby mode. Instruction com-
mands (Op Code), addresses, and data are all input
from the most significant bit (MSB) first.

TABLE 4-4:

DEVICE OPERATION INSTRUCTIONS

Instruction

Description

Op Code Cycle

1

1. One bus cycle is eight clock periods.

Address 

Cycle(s)

2

2. Address bits above the most significant bit of each density can be V

IL

 or V

IH

.

Dummy 

Cycle(s)

Data

Cycle(s)

Read

Read Memory

0000 0011b (03H)

3

0

1  to 

High-Speed Read

Read Memory at higher speed

0000 1011b (0BH)

3

1

1  to 

4 KByte Sector-Erase

3

3. 4KByte Sector Erase addresses: use A

MS

-A

12,

 remaining addresses are don’t care but must be set either at V

IL

 or V

IH.

Erase 4 KByte of 
memory array

0010 0000b (20H)

3

0

0

32 KByte Block-Erase

4

4. 32KByte Block Erase addresses: use A

MS

-A

15,

 remaining addresses are don’t care but must be set either at V

IL

 or V

IH.

Erase 32 KByte block 
of memory array

0101 0010b (52H)

3

0

0

64 KByte Block-Erase

5

5. 64KByte Block Erase addresses: use A

MS

-A

16,

 remaining addresses are don’t care but must be set either at V

IL

 or V

IH.

Erase 64 KByte block 
of memory array

1101 1000b (D8H)

3

0

0

Chip-Erase

Erase Full Memory Array

0110 0000b (60H) or 
1100 0111b (C7H)

0

0

0

Byte-Program

To Program One Data Byte

0000 0010b (02H)

3

0

1

AAI-Word-Program

6

6. To continue programming to the next sequential address location, enter the 8-bit command, ADH, followed by 2 bytes of data 

to be programmed. Data Byte 0 will be programmed into the initial address [A

23

-A

1

] with A

0

=0, Data Byte 1 will be pro-

grammed into the 
initial address [A

23

-A

1

] with A

0

=1.

Auto Address Increment 
Programming

1010 1101b (ADH)

3

0

2  to 

RDSR

7

7. The Read-Status-Register is continuous with ongoing clock cycles until terminated by a low to high transition on CE#.

Read-Status-Register

0000 0101b (05H)

0

0

1  to 

EWSR

Enable-Write-Status-Register

0101b 0000b (50H)

0

0

0

WRSR

Write-Status-Register

0000 0001b (01H)

0

0

1

WREN

Write-Enable

0000 0110b (06H)

0

0

0

WRDI

Write-Disable

0000 0100b (04H)

0

0

0

RDID

8

8. Manufacturer’s ID is read with A

0

=0, and Device ID is read with A

0

=1. All other address bits are 00H. The Manufacturer’s ID 

and device ID output stream is continuous until terminated by a low-to-high transition on CE#.

Read-ID

1001 0000b (90H) or 
1010 1011b (ABH)

3

0

1  to 

JEDEC-ID

JEDEC ID read

1001 1111b (9FH)

0

0

3  to 

EBSY

Enable SO to output RY/BY# 
status during AAI programming

0111 0000b (70H)

0

0

0

DBSY

Disable SO as RY/BY# 
status during AAI programming

1000 0000b (80H)

0

0

0

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DS20005045C-page 8

 

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4.4.1

READ (25 MHz)

The Read instruction, 03H, supports up to 25 MHz
Read. The device outputs the data starting from the
specified address location. The data output stream is
continuous through all addresses until terminated by a
low to high transition on CE#. The internal address
pointer will automatically increment until the highest
memory address is reached. Once the highest memory
address is reached, the address pointer will automati-

cally increment to the beginning (wrap-around) of the
address space. Once the data from address location
FFFFFH has been read, the next output will be from
address location 00000H.

The Read instruction is initiated by executing an 8-bit
command, 03H, followed by address bits [A23-A0].
CE# must remain active low for the duration of the
Read cycle. See 

Figure 4-3

 for the Read sequence.

FIGURE 4-3:

READ SEQUENCE

4.4.2

HIGH-SPEED-READ (66 MHz)

1

The High-Speed-Read instruction, supporting up to
66 MHz Read, is initiated by executing an 8-bit com-
mand, 0BH, followed by address bits [A23-A0] and a
dummy byte. CE# must remain active low for the dura-
tion of the High-Speed-Read cycle. See 

Figure 4-4

 for

the High-Speed-Read sequence.

Following a dummy cycle, the High-Speed-Read
instruction outputs the data starting from the specified
address location. The data output stream is continuous
through all addresses until terminated by a low to high
transition on CE#. The internal address pointer will
automatically increment until the highest memory
address is reached. Once the highest memory address
is reached, the address pointer will automatically incre-
ment to the beginning (wrap-around) of the address
space. Once the data from address location FFFFFH
has been read, the next output will be from address
location 00000H.

FIGURE 4-4:

HIGH-SPEED-READ SEQUENCE

1296 ReadSeq_0.0

CE#

SO

SI

SCK

ADD.

0 1 2 3 4 5 6 7 8

ADD.

ADD.

03

HIGH IMPEDANCE

15 16

23 24

31 32

39 40

70

47

48

55 56

63 64

N+2

N+3

N+4

N

N+1

D

OUT

MSB

MSB

MSB

MODE 0

MODE 3

D

OUT

D

OUT

D

OUT

D

OUT

1.66 MHz operations occur under the conditions specified in 

Table 5-6 on page 19

.

1296 HSRdSeq.0

CE#

SO

SI

SCK

ADD.

0 1 2 3 4 5

6 7 8

ADD.

ADD.

0B

HIGH IMPEDANCE

15 16

23 24

31 32

39 40

47 48

55 56

63 64

N+2

N+3

N+4

N

N+1

X

MSB

MSB

MSB

MODE 0

MODE 3

D

OUT

D

OUT

D

OUT

D

OUT

80

71 72

D

OUT

Note: X = Dummy Byte: 8 Clocks Input Dummy Cycle (V

IL

 or V

IH

)

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DS20005045C-page 9

SST25VF080B

4.4.3

BYTE-PROGRAM

The Byte-Program instruction programs the bits in the
selected byte to the desired data. The selected byte
must be in the erased state (FFH) when initiating a Pro-
gram operation. A Byte-Program instruction applied to a
protected memory area will be ignored.

Prior to any Write operation, the Write-Enable (WREN)
instruction must be executed. CE# must remain active
low for the duration of the Byte-Program instruction.

The Byte-Program instruction is initiated by executing
an 8-bit command, 02H, followed by address bits [A

23

-

A

0

]. Following the address, the data is input in order

from MSB (bit 7) to LSB (bit 0). CE# must be driven
high before the instruction is executed. The user may
poll the Busy bit in the software status register or wait
T

BP

 for the completion of the internal self-timed Byte-

Program operation. See 

Figure 4-5

 for the Byte-Pro-

gram sequence.

FIGURE 4-5:

BYTE-PROGRAM SEQUENCE

4.4.4

AUTO ADDRESS INCREMENT (AAI) 
WORD-PROGRAM

The AAI program instruction allows multiple bytes of
data to be programmed without re-issuing the next
sequential address location. This feature decreases
total programming time when multiple bytes or entire
memory array is to be programmed. An AAI Word pro-
gram instruction pointing to a protected memory area
will be ignored. The selected address range must be in
the erased state (FFH) when initiating an AAI Word
Program operation. While within AAI Word Program-
ming sequence, only the following instructions are
valid: for software end-of-write detection—AAI Word
(ADH), WRDI (04H), and RDSR (05H); for hardware
end-of-write detection—AAI Word (ADH) and WRDI
(04H). There are three options to determine the com-
pletion of each AAI Word program cycle: hardware
detection by reading the Serial Output, software detec-
tion by polling the BUSY bit in the software status reg-
ister, or wait T

BP.

 Refer to“End-of-Write Detection” for

details.

Prior to any write operation, the Write-Enable (WREN)
instruction must be executed. Initiate the AAI Word
Program instruction by executing an 8-bit command,
ADH, followed by address bits [A

23

-A

0

]. Following the

addresses, two bytes of data are input sequentially,
each one from MSB (Bit 7) to LSB (Bit 0). The first byte
of data (D0) is programmed into the initial address [A

23

-

A

1

] with A

0

=0, the second byte of Data (D1) is pro-

grammed into the initial address [A

23

-A

1

] with A

0

=1.

CE# must be driven high before executing the AAI

Word Program instruction. Check the BUSY status
before entering the next valid command. Once the
device indicates it is no longer busy, data for the next
two sequential addresses may be programmed, fol-
lowed by the next two, and so on. 

When programming the last desired word, or the high-
est unprotected memory address, check the busy sta-
tus using either the hardware or software (RDSR
instruction) method to check for program completion.
Once programming is complete, use the applicable
method to terminate AAI. If the device is in Software
End-of-Write Detection mode, execute the Write-Dis-
able (WRDI) instruction, 04H. If the device is in AAI
Hardware End-of-Write Detection mode, execute the
Write-Disable (WRDI) instruction, 04H, followed by the
8-bit DBSY command, 80H. There is no wrap mode
during AAI programming once the highest unprotected
memory address is reached. See Figures 

4-8

 and 

4-9

for the AAI Word programming sequence. 

4.4.5

END-OF-WRITE DETECTION

There are three methods to determine completion of a
program cycle during AAI Word programming: hard-
ware detection by reading the Serial Output, software
detection by polling the BUSY bit in the Software Status
Register, or wait T

BP.

 The Hardware End-of-Write

detection method is described in the section below.

1296 ByteProg.0

CE#

SO

SI

SCK

ADD.

0 1 2 3 4 5 6 7 8

ADD.

ADD.

D

IN

02

HIGH IMPEDANCE

15 16

23 24

31 32

39

MODE 0

MODE 3

MSB

MSB

MSB

LSB

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 2015 Microchip Technology Inc.

4.4.6

HARDWARE END-OF-WRITE 
DETECTION

The Hardware End-of-Write detection method elimi-
nates the overhead of polling the Busy bit in the Soft-
ware Status Register during an AAI Word program
operation. The 8-bit command, 70H, configures the
Serial Output (SO) pin to indicate Flash Busy status
during AAI Word programming. (see 

Figure 4-6

) The 8-

bit command, 70H, must be executed prior to initiating
an AAI Word-Program instruction. Once an internal
programming operation begins, asserting CE# will
immediately drive the status of the internal flash status

on the SO pin. A ‘0’ indicates the device is busy and a
‘1’ indicates the device is ready for the next instruction.
De-asserting CE# will return the SO pin to tri-state.
While in AAI and Hardware End-of-Write detection
mode, the only valid instructions are AAI Word (ADH)
and WRDI (04H).

To exit AAI Hardware End-of-Write detection, first exe-
cute WRDI instruction, 04H, to reset the Write-Enable-
Latch bit (WEL=0) and AAI bit. Then execute the 8-bit
DBSY command, 80H, to disable RY/BY# status during
the AAI command. See Figures 

4-7

 and 

4-8

.

FIGURE 4-6:

ENABLE SO AS HARDWARE RY/BY# DURING AAI PROGRAMMING

FIGURE 4-7:

DISABLE SO AS HARDWARE RY/BY# DURING AAI PROGRAMMING

CE#

SO

SI

SCK

0 1 2 3 4 5 6 7

70

HIGH IMPEDANCE

MODE 0

MODE 3

1296 EnableSO.0

MSB

CE#

SO

SI

SCK

0 1 2 3 4 5 6 7

80

HIGH IMPEDANCE

MODE 0

MODE 3

1296 DisableSO.0

MSB

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Microchip Technology Inc.
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