SST25VF040B View Datasheet(PDF) - Silicon Storage Technology

Part Name

Description

Manufacturer

SST25VF040B

4 Mbit SPI Serial Flash

Silicon Storage Technology 

4 Mbit SPI Serial Flash

SST25VF040B

Chip-Erase

The Chip-Erase instruction clears all bits in the device to

FFH. A Chip-Erase instruction will be ignored if any of the

memory area is protected. Prior to any Write operation, the

Write-Enable (WREN) instruction must be executed. CE#

must remain active low for the duration of the Chip-Erase

instruction sequence. The Chip-Erase instruction is initiated

Data Sheet

by executing an 8-bit command, 60H or C7H. CE# must be

driven high before the instruction is executed. The user may

poll the Busy bit in the software status register or wait TCE

for the completion of the internal self-timed Chip-Erase

cycle. See Figure 15 for the Chip-Erase sequence.

CE#

MODE 3

SCK MODE 0

0 1 2345 6 7

SI

SO

FIGURE 15: Chip-Erase Sequence

60 or C7

MSB

HIGH IMPEDANCE

1295 ChEr.0

Read-Status-Register (RDSR)

The Read-Status-Register (RDSR) instruction allows read-

ing of the status register. The status register may be read at

any time even during a Write (Program/Erase) operation.

When a Write operation is in progress, the Busy bit may be

checked before sending any new commands to assure that

the new commands are properly received by the device.

CE# must be driven low before the RDSR instruction is

entered and remain low until the status data is read. Read-

Status-Register is continuous with ongoing clock cycles

until it is terminated by a low to high transition of the CE#.

See Figure 16 for the RDSR instruction sequence.

CE#

MODE 3 0

1

2

3

4

5

6

SCK MODE 0

SI

05

MSB

HIGH IMPEDANCE

SO

7

8

9 10 11 12 13 14

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

MSB

Status

Register Out

1295 RDSRseq.0

FIGURE 16: Read-Status-Register (RDSR) Sequence

Write-Enable (WREN)

The Write-Enable (WREN) instruction sets the Write-

Enable-Latch bit in the Status Register to 1 allowing Write

operations to occur. The WREN instruction must be exe-

cuted prior to any Write (Program/Erase) operation. The

WREN instruction may also be used to allow execution of

the Write-Status-Register (WRSR) instruction; however,

the Write-Enable-Latch bit in the Status Register will be

cleared upon the rising edge CE# of the WRSR instruction.

CE# must be driven high before the WREN instruction is

executed.

©2009 Silicon Storage Technology, Inc.

17

S71295-05-000

10/09

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