May 7, 2004 S29PL127H_129H_00A1
S29PL127H/S29PL129H
47
Pre l i m i n a r y
cause that bank to set DQ5 = 1, or cause the DQ7 and DQ6 status bits to indicate
the operation was successful. However, a succeeding read will show that the data
is still “0.” Only erase operations can convert a “0” to a “1.”
Unlock Bypass Command Sequence
The unlock bypass feature allows the system to program data to a bank faster
than using the standard program command sequence. The unlock bypass com-
mand sequence is initiated by first writing two unlock cycles. This is followed by
a third write cycle containing the unlock bypass command, 20h. That bank 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 se-
quence 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.
Table 16 shows the requirements for the command sequence.
During the unlock bypass mode, only the Unlock Bypass Program and Unlock By-
pass Reset commands are valid. To exit the unlock bypass mode, the system
must issue the two-cycle unlock bypass reset command sequence. (See
Table 14)
The device offers accelerated program operations through the WP#/ACC pin.
When the system asserts VHH on the WP#/ACC pin, the device automatically en-
ters the Unlock Bypass mode. The system may then write the two-cycle Unlock
Bypass program command sequence. The device uses the higher voltage on the
WP#/ACC pin to accelerate the operation. Note that the WP#/ACC pin must not
be at VHH any operation other than accelerated programming, or device damage
may result. In addition, the WP#/ACC pin must not be left floating or uncon-
nected; inconsistent behavior of the device may result.
Figure 5 illustrates the algorithm for the program operation. Refer to the
Erase