E S I
E S I
ADVANCED INFORMATION
Excel Semiconductor inc.
Write Enable (WREN)
Write Disable (WRDI)
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 Pro-
gram (PP or PPP), Erase (SE, BE or PE) and Write
Status Register (WRSR) instruction. The Write
Enable (WREN) instruction is entered by driving
Chip Select (CS#) Low, sending the instruction code,
and then driving Chip Select (CS#) High.
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 (CS#) Low, sending the instruction code, and
then driving Chip Select (CS#) High.
The Write Enable (WEL) bit is reset under the follow-
ing conditions :
- Power-up
- WRDI instruction completion
- WRSR instruction completion
- PP instruction completion
- SE instruction completion
- BE instruction completion
CS#
0
1
2
3
4
5
6
7
SCK
SI
Instruction
0
0
0
0
0
1
1
0
High Impedance
SO
Figure 4. Write Enable ( WREN ) Instruction Sequence
CS#
SCK
SI
0
1
2
3
4
5
6
7
Instruction
0
0
0
0
0
1
0
0
High Impedance
SO
Figure 5. Write Disable ( WRDI ) Instruction Sequence
11
Rev. 0D May, 11, 2006
ES25P80
EXCELSEMI [ EXCEL SEMICONDUCTOR INC. ]
