Write Enable (WREN)
The Write Enable (WREN) instruction (Figure 4.) sets the
Write Enable Latch (WEL) bit.
The Write Enable Latch (WEL) bit must be set prior to every
Page Program (PP), Sector Erase (SE), Bulk Erase (BE) and
Write Status Register (WRSR) instruction.
A25L40P Series
The Write Enable (WREN) instruction is entered by driving
Chip Select ( S ) Low, sending the instruction code, and then
driving Chip Select ( S ) High.
Figure 4. Write Enable (WREN) Instruction Sequence
S
01 23 45 67
C
Instruction
D
High Impedance
Q
Write Disable (WRDI)
The Write Disable (WRDI) instruction (Figure 5.) resets the
Write Enable Latch (WEL) bit.
The Write Disable (WRDI) instruction is entered by driving Chip
Select ( S ) Low, sending the instruction code, and then driving
Chip The Write Enable Latch (WEL) bit is reset under the
following conditions:
﹣ Power-up
﹣ Write Disable (WRDI) instruction completion
﹣ Write Status Register (WRSR) instruction completion
﹣ Page Program (PP) instruction completion
﹣ Sector Erase (SE) instruction completion
﹣ Bulk Erase (BE) instruction completion
Figure 5. Write Disable (WRDI) Instruction Sequence
S
01 23 45 67
C
Instruction
D
High Impedance
Q
PRELIMINARY (May, 2007, Version 0.4)
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