11AAXXX/11LCXXX
The following is a list of conditions under which the
write enable latch will be reset:
4.4
Write Enable (WREN) and Write
Disable (WRDI) Instructions
• Power-up
The 11XX contains a write enable latch. See Table 6-1
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 WRDIinstruction will reset the latch.
• WRDIinstruction successfully executed
• WRSRinstruction successfully executed
• WRITEinstruction successfully executed
• ERALinstruction successfully executed
• SETALinstruction successfully executed
Note: The WRENand WRDIinstructions must
be terminated with a NoMAK following
the command byte. If a NoMAK is not
received at this point, the command will
be considered invalid, and the device
will go into Idle mode without responding
with a SAK or executing the command.
FIGURE 4-4:
WRITE ENABLE COMMAND SEQUENCE
Device Address
Standby Pulse
Start Header
SCIO
0 1 0 1 0 1 0 1
1 0 1 0 0 0 0 0
Command
SCIO
1 0 0 1 0 1 1 0
FIGURE 4-5:
WRITE DISABLE COMMAND SEQUENCE
Device Address
Standby Pulse
Start Header
SCIO
SCIO
0 1 0 1 0 1 0 1
1 0 1 0 0 0 0 0
Command
1 0 0 1 0 0 0 1
© 2008 Microchip Technology Inc.
Preliminary
DS22067E-page 13