s29al008d Meet Spansion Inc., s29al008d Datasheet - Page 23

• Manufacturer Part Number: s29al008d
• Description: 8 Megabit 1 M X 8-bit/512 K X 16-bit Cmos 3.0 Volt-only Boot Sector Flash Memory
• Manufacturer: Meet Spansion Inc.

8.5
November 27, 2007 S29AL008D_00_A10
Unlock Bypass Command Sequence
The unlock bypass feature allows the system to program bytes or words to the device faster than using the
standard program command sequence. The unlock bypass command sequence is initiated by first writing two
unlock cycles. This is followed by a third write cycle containing the unlock bypass command, 20h. The device
then enters the unlock bypass mode. A two-cycle unlock bypass program command sequence is all that is
required to program in this mode. The first cycle in this sequence contains the unlock bypass program
command, A0h; the second cycle contains the program address and data. Additional data is programmed in
the same manner. This mode dispenses with the initial two unlock cycles required in the standard program
command sequence, resulting in faster total programming time.
command sequence.
During the unlock bypass mode, only the Unlock Bypass Program and Unlock Bypass Reset commands are
valid. To exit the unlock bypass mode, the system must issue the two-cycle unlock bypass reset command
sequence. The first cycle must contain the data 90h; the second cycle the data 00h. Addresses are don’t care
for both cycles. The device then returns to reading array data.
Table 8.1
parameters, and
Note
See
Table 8.1 on page 26
illustrates the algorithm for the program operation. See
Figure 15.5 on page 39
for program command sequence.
D a t a
Increment Address
S h e e t
Figure 8.1 Program Operation
S29AL008D
for timing diagrams.
in progress
Embedded
algorithm
Program
No
Command Sequence
Write Program
Last Address?
Programming
from System
Verify Data?
Completed
Data Poll
START
Table 8.1
Erase/Program Operations on page 39
Yes
Yes
shows the requirements for the
No
for
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