
February 20, 2007 S29NS-P_00_A1
S29NS-P MirrorBit
TM
Flash Family
55
D a t a
S h e e t
( A d v a n c e
I n f o r m a t i o n )
Figure 7.2
PPB Program/Erase Algorithm
7.3
Dynamic Protection Bits
Dynamic Protection Bits are volatile and unique for each sector and can be individually modified. DYBs only
control the protection scheme for unprotected sectors that have their PPBs cleared (erased to
1
). By issuing
the DYB Set or Clear command sequences, the DYBs are set (programmed to
0
) or cleared (erased to
1
),
thus placing each sector in the protected or unprotected state respectively. This feature allows software to
easily protect sectors against inadvertent changes yet does not prevent the easy removal of protection when
changes are needed.
Read Byte Twice
Addr = SA0
Enter PPB
Command Set.
Addr = BA
Program PPB Bit.
Addr = SA
DQ5 = 1
Yes
Yes
Yes
No
No
No
Yes
DQ6 =
Toggle
DQ6 =
Toggle
Read Byte.
Addr = SA
PASS
FAIL
Exit PPB
Command Set
DQ0 =
'1' (Erase)
'0' (Pgm.)
Read Byte Twice
Addr = SA0
No
Wait 500 μs