
CAT25010, CAT25020, CAT25040
Write Status Register
The Status Register is written by sending a WRSR
instruction according to timing shown in Figure 7. Only bits
2 and 3 can be written using the WRSR command.
Write Protection
When WP input is low all write operations to the memory
array and Status Register are inhibited. WP going low while
CS is still low will interrupt a write operation. If the internal
write cycle has already been initiated, WP going low will
have no effect on any write operation to the Status Register
or memory array. The WP input timing is shown in Figure 8.
CS
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
SCK
OPCODE
DATA IN
SI
0
0
0
0
0
0
0
1
7
6
5
4
3
2
1
0
MSB
SO
HIGH IMPEDANCE
Dashed Line = mode (1, 1)
Figure 7. WRSR Timing
t WPS
t WPH
CS
SCK
WP
WP
Dashed Line = mode (1, 1)
Figure 8. WP Timing
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