©2014 Silicon Storage Technology, Inc.

DS20005016C

11/14

8

512 Kbit / 1 Mbit / 2 Mbit / 4 Mbit 1.8V SPI Serial Flash

SST25WF512 / SST25WF010 / SST25WF020 / SST25WF040

EOL Data Sheet

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 pro-

tection. During an internal Erase or Program operation, the status register may be read only to deter-

mine the completion of an operation in progress. Table 4 describes the function of each bit in the

software status register.

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.

Write Enable Latch (WEL)

The Write-Enable-Latch bit indicates the status of the internal Write-Enable-Latch memory. If the WEL

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 Write (Program/Erase) commands. The Write-

Enable-Latch bit is automatically reset under the following conditions:

•

Device Reset

•

Power-up

•

Write-Disable (WRDI) instruction completion

•

Byte-Program instruction completion

•

Auto Address Increment (AAI) programming is completed or reached its highest unpro-

tected memory address

•

Sector-Erase instruction completion

•

Block-Erase instruction completion

•

Chip-Erase instruction completion

•

Write-Status-Register instructions

Table 4: 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

0R

1

WEL

1 = Device is memory Write enabled

0 = Device is not memory Write enabled

0R

2

BP0

Indicate current level of block write protection (See Tables 5 through 8)

1

R/W

3

BP1

Indicate current level of block write protection (See Tables 5 through 8)

1

R/W

4

BP2

Indicate current level of block write protection (See Tables 5 through 8)

1

R/W

5

RES

Reserved for future use

0

N/A

6

AAI

Auto Address Increment Programming status

1 = AAI programming mode

0 = Byte-Program mode

0R

7

BPL

1 = BP1 and BP0 are read-only bits

0 = BP1 and BP0 are read/writable

0

R/W

T4.1 20005016