11. CONTROL AND STATUS REGISTER
The Read Status Register instruction can be used to provide status on the availability of the Flash
memory array, if the device is write enabled or disabled, the state of write protection and the Quad
SPI setting. The Write Status Register instruction can be used to configure the devices write
protection features and Quad SPI setting. Write access to the Status Register is controlled by in
some cases of the /WP pin.
11.1 STATUS REGISTER
BUSY is a read only bit in the status register (S0) that is set to a 1 state when the device is
executing a Page Program, Sector Erase, Block Erase, Chip Erase or Write Status Register
instruction. During this time the device will ignore further instruction except for the Read Status
Register and Erase Suspend instruction (see tW, tPP, tSE, tBE1, tBE2 and tCE in AC
Characteristics). When the program, erase or write status register instruction has completed, the
BUSY bit will be cleared to a 0 state indicating the device is ready for further instructions.
11.1.2 Write Enable Latch (WEL)
Write Enable Latch (WEL) is a read only bit in the status register (S1) that is set to a 1 after
executing a Write Enable instruction. The WEL status bit is cleared to a 0, When device is write
disabled. A write disable state occurs upon power-up or after any of the following instructions:
Write Disable, Page Program, Sector Erase, Block Erase, Chip Erase and Write Status Register.
11.1.3 Block Protect Bits (BP2, BP1, BP0)
The Block Protect Bits (BP2, BP1, BP0) are non-volatile read/write bits in the status register (S4,
S3, and S2) that provide write protection control and status. Block protect bits can be set using the
Write Status Register Instruction (see tW in AC characteristics). All none or a portion of the memory
array can be protected from Program and Erase instructions (see Status Register Memory
Protection table). The factory default setting for the Block Protection Bits is 0, none of the array
11.1.4 Top/Bottom Block protect (TB)
The non-volatile Top/Bottom bit (TB) controls if the Block Protect Bits (BP2, BP1, BP0) protect from
the Top (TB=0) or the Bottom (TB=1) of the array as shown in the Status Register Memory
Protection table. The factory default setting is TB=0. The TB bit can be set with the Write Status
Register Instruction depending on the state of the SRP0, SRP1 and WEL bits.
11.1.5 Sector/Block Protect (SEC)
The non-volatile Sector protect bit (SEC) controls if the Block Protect Bits (BP2, BP1, BP0) protect
4KB Sectors (SEC=1)or 64KB Blocks (SEC=0) in the Top (TB=0) or the Bottom (TB=1) of the array
as shown in the Status Register Memory protection table. The default setting is SEC=0.