s71ws256jc0 Meet Spansion Inc., s71ws256jc0 Datasheet - Page 75

• Manufacturer Part Number: s71ws256jc0
• Description: Stacked Multi-chip Product Mcp 128/64 Megabit 8m/4m X 16-bit Cmos 1.8 Volt-only, Simultaneous Read/write, Burst Mode Flash Memory With Cellularram
• Manufacturer: Meet Spansion Inc.

14.11 Password Program Command
June 24, 2005 S29WS-J_M0_A4
Notes:
1.
2.
The Password Program Command permits programming the password that is used as part of the
hardware protection scheme. The actual password is 64-bits long. 4 Password Program com-
mands are required to program the password. The user must enter the unlock cycle, password
program command (38h) and the program address/data for each portion of the password when
programming. There are no provisions for entering the 2-cycle unlock cycle, the password pro-
gram command, and all the password data. There is no special addressing order required for
programming the password. Also, when the password is undergoing programming, Simultaneous
Operation is disabled. Read operations to any memory location will return the programming status
except DQ7. Once programming is complete, the user must issue a Read/Reset command to the
device to normal operation. Once the Password is written and verified, the Password Mode Locking
Bit must be set in order to prevent verification. The Password Program Command is only capable
of programming “0”s. Programming a “1” after a cell is programmed as a “0” results in a time-
out by the Embedded Program Algorithm™ with the cell remaining as a “0”. The password is all
F’s when shipped from the factory. All 64-bit password combinations are valid as a password.
See
See the section on DQ3 for information on the sector erase timer
Table 14.5
for erase command sequence.
D a t a
No
Command Sequence
Erasure Completed
S h e e t
Write Erase
from System
Data = FFh?
Data Poll
S29WS128J/064J
Figure 14.3 Erase Operation
START
Yes
Embedded
Erase
algorithm
in progress
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