SST25PF080B View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

SST25PF080B

8 Mbit 2.3-3.6V SPI Serial Flash

Microchip Technology 

SST25PF080B

4.8.5 WRITE-STATUS-REGISTER (WRSR)

The Write-Status-Register instruction writes new val-

ues to the BP2, BP1, BP0, and BPL bits of the status

register. CE# must be driven low before the command

sequence of the WRSR instruction is entered and

driven high before the WRSR instruction is executed.

See Figure 4-17 for EWSR or WREN and WRSR

instruction sequences.

Executing the Write-Status-Register instruction will be

ignored when WP# is low and BPL bit is set to “1”.

When the WP# is low, the BPL bit can only be set from

“0” to “1” to lock-down the status register, but cannot be

reset from “1” to “0”. When WP# is high, the lock-down

function of the BPL bit is disabled and the BPL, BP0,

BP1, and BP2 bits in the status register can all be

changed. As long as BPL bit is set to 0 or WP# pin is

driven high (VIH) prior to the low-to-high transition of the

CE# pin at the end of the WRSR instruction, the bits in

the status register can all be altered by the WRSR

instruction. In this case, a single WRSR instruction can

set the BPL bit to “1” to lock down the status register as

well as altering the BP0, BP1, and BP2 bits at the same

time. See Table 4-1 for a summary description of WP#

and BPL functions.

CE#

MODE 3

SCK MODE 0

0 123456 7

SI

50 or 06

MSB

SO

MODE 3 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

MODE 0

01

MSB

HIGH IMPEDANCE

STATUS

REGISTER IN

76543210

MSB

25137 EWSR.0

FIGURE 4-17:

ENABLE-WRITE-STATUS-REGISTER (EWSR) OR WRITE-ENABLE (WREN) AND

WRITE-STATUS-REGISTER (WRSR) SEQUENCE

DS25134A-page 16

 2012 Microchip Technology Inc.

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