20 / 37 page
SA25F020 Advanced Information
SAIFUN
20
Write Enable (WREN)
The device powers up in the Write Disable
state when VCC is applied. All programming
instructions must be preceded by a WREN
instruction. The instruction sequence is
shown in Figure 11, with SO in high
impedance.
Write Disable (WRDI)
To protect the device against inadvertent
writes, the WRDI instruction disables all
programming
modes.
The
WRDI
instruction is independent of the WP pin's
status. The WREN instruction should be
executed after the WRDI instruction to
re-enable all programming modes. The
instruction sequence is shown in Figure 12,
with SO in high impedance.
3
27
6
5
4
0
Instruction
SCK
SI
1
CS
Figure 11. Write Enable (WREN) Instruction Sequence
3
27
6
5
4
0
Instruction
SCK
SI
1
CS
Figure 12. Write Disable (WRDI) Instruction Sequence
Italian ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
