25LCXXX
3.4 Write Enable (WREN) and Write
Disable (WRDI)
The 25LCXXX contains a write enable latch. See
Table 5-1 for the write-protect functionality matrix. This
latch must be set before any write operation will be com-
pleted internally. The WREN instruction will set the latch,
and the WRDI will reset the latch.
The following is a list of conditions under which the
write enable latch will be reset:
• Power-up
• WRDI instruction successfully executed
• WRSR instruction successfully executed
• WRITE instruction successfully executed
FIGURE 3-4: WRITE ENABLE SEQUENCE (WREN)
CS
SCK
01234567
SI
00000110
High-Impedance
SO
FIGURE 3-5: WRITE DISABLE SEQUENCE (WRDI)
CS
SCK
01234567
SI
0 0 0 0 0 1 10 0
High-Impedance
SO
© 2009 Microchip Technology Inc.
Preliminary
DS22131C-page 11