11AA02E48/11AA02E64
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 11AA02EXX 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
completed internally. The WRENinstruction 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
DS20002122D-page 12
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