W25B40 Datasheet, PDF (14/36 Pages) Winbond – 4M-BIT SERIAL FLASH MEMORY WITH BOOT AND PARAMETER SECTORS

W25B40/W25B40A
8.2.3 Write Disable (04h)
The Write Disable instruction (Figure 4) resets the Write Enable Latch (WEL) bit in the Status Register
to a 0. The Write Disable instruction is entered by driving /CS low, shifting the instruction code “04h”
into the DI pin and then driving /CS high. Note that the WEL bit is automatically reset after Power-up
and upon completion of the Write Status Register, Page Program, Sector Erase, and Chip Erase
instructions.
Figure 4. Write Disable Instruction Sequence Diagram
8.2.4 Write Enable (06h)
The Write Enable instruction (Figure 5) sets the Write Enable Latch (WEL) bit in the Status Register to
a 1. The WEL bit must be set prior to every Page Program, Sector Erase, Chip Erase and Write Status
Register instruction. The Write Enable instruction is entered by driving /CS low, shifting the instruction
code “06h” into the Data Input (DI) pin on the rising edge of CLK, and then driving /CS high.
Figure 5. Write Enable Instruction Sequence Diagram
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