© 2009 Microchip Technology Inc. DS21828F-page 9
25AA320A/25LC320A
2.4 Write Enable (WREN) and Write
Disable (WRDI)
The 25XX320A contains a write enable latch. See
Table 2-4 for the write-protect functionality matrix. This
latch must be set before any write operation will be
completed 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 2-4: WRITE ENABLE SEQUENCE (WREN)
FIGURE 2-5: WRITE DISABLE SEQUENCE (WRDI)
SCK
0 2345671
SI
High-Impedance
SO
CS
010000 01
SCK
0 2345671
SI
High-Impedance
SO
CS
010000 01
0
