LH28F400SU-NC
4M (512K × 8, 256K × 16) Flash Memory
START
READ COMPATIBLE
STATUS REGISTER
CSR.7 = 0
1
WRITE 47H
WRITE CONFIRM
DATA/ADDRESS
READ COMPATIBLE
STATUS REGISTER
CSR.7 = 0
1
CSR.4, 5 = 1 (NOTE)
0
OPERATION
COMPLETE
BUS
OPERATION
COMMAND
COMMENTS
Read
Check CSR.7
1 = WSM Ready
0 = WSM Busy
Write
Reset
D = 47H
Write Protect A = X
Write
Reset
Confirm
D = D0H
A = 0FFH
(A9 - A8 = 0, A7 - A0 = 1,
Others = X)
Read
Read
Check CSR.7
1 = WSM Ready
0 = WSM Busy
Check CSR.4, 5
1 = Unsuccesful
0 = Successful
NOTE:
If CSR.4, 5 is set, as it is command sequence error,
should be cleared before further attempts are initiated.
Reset Write Protect command enables Write/Erase
operation to all blocks.
Write FFH after the last operation to reset device to
Read Array Mode.
See Command Bus Cycle notes for description of codes.
Figure 14. Reset Write Protect
28F400SUT-NC60-12
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