Datasheet

11AA02E48/11AA02E64
DS20002122B-page 14  2008-2013 Microchip Technology Inc.
4.6 Write Status Register (WRSR)
Instruction
The WRSR instruction allows the user to select one of
four levels of protection for the array by writing to the
appropriate bits in the STATUS register. The array is
divided up into four segments. The user has the ability
to write-protect none, one, two, or all four of the seg-
ments of the array. The partitioning is controlled as
illustrated in Table 4- 3.
After transmitting the STATUS register data, the master
must transmit a NoMAK during the Acknowledge
sequence in order to initiate the internal write cycle.
TABLE 4-3: ARRAY PROTECTION
FIGURE 4-7: WRITE STATUS REGISTER COMMAND SEQUENCE
Note: The WRSR instruction must be terminated
with a NoMAK following the data 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.
BP1 BP0
Array Addresses
Write-Protected
00
none
01
upper 1/4
(C0h-FFh)
10
upper 1/2
(80h-FFh)
11
all
(00h-FFh)
11010100
Start Header
SCIO
Device Address
MAK
00001010
MAK
Command
10101101
MAK
NoSAK
SAK
Standby Pulse
SCIO
SAK
7654
Status Register Data
3210
NoMAK
SAK
Twc