s71ws256nc0bawa30 Meet Spansion Inc., s71ws256nc0bawa30 Datasheet - Page 60

• Manufacturer Part Number: s71ws256nc0bawa30
• Description: Stacked Multi-chip Product Mcp 256/512/128 Megabit 32m/16m/8m X 16 Bit Cmos 1.8 Volt-only Simultaneous Read/write, Burst-mode Flash Memory With 128/64megabit 8m/4m X 16-bit Psram.
• Manufacturer: Meet Spansion Inc.

11.3
58
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 (pro-
grammed 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 in-
advertent changes yet does not prevent the easy removal of protection when changes are
needed.
No
Figure 11.2 PPB Program/Erase Algorithm
Program PPB Bit.
Read Byte Twice
Read Byte Twice
Command Set.
A d v a n c e
Issue Reset
Addr = SA0
Addr = SA0
Enter PPB
Addr = BA
Addr = SA
Command
S71WS-Nx0 Based MCPs
DQ5 = 1?
Toggle?
Toggle?
DQ6 =
DQ6 =
FAIL
Yes
Yes
Yes
Command Set
No
No
Exit PPB
No
I n f o r m a t i o n
Wait 500 µs
Read Byte.
'0' (Pgm.)?
Addr = SA
'1' (Erase)
DQ0 =
PASS
Yes
S71WS-N_01_A4 September 15, 2005