S29AL008D55BAI022 Ver la hoja de datos (PDF) - Spansion Inc.

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S29AL008D55BAI022

8 Megabit (1 M x 8-Bit/512 K x 16-Bit)CMOS 3.0 Volt-only Boot Sector Flash Memory

Spansion Inc. 

Data Sheet

program set-up command. The program address and data are written next, which

in turn initiate the Embedded Program algorithm. The system is not required to

provide further controls or timings. The device automatically provides internally

generated program pulses and verifies the programmed cell margin. Table 5, on

page 25 shows the address and data requirements for the byte program com-

mand sequence.

When the Embedded Program algorithm is complete, the device then returns to

reading array data and addresses are no longer latched. The system can deter-

mine the status of the program operation by using DQ7, DQ6, or RY/BY#. See

Write Operation Status, on page 27 for information on these status bits.

Any commands written to the device during the Embedded Program Algorithm

are ignored. Note that a hardware reset immediately terminates the program-

ming operation. The program command sequence should be reinitiated once the

device resets to reading array data, to ensure data integrity.

Programming is allowed in any sequence and across sector boundaries. A bit

cannot be programmed from a 0 back to a 1. Attempting to do so may halt

the operation and set DQ5 to 1, or cause the Data# Polling algorithm to indicate

the operation was successful. However, a succeeding read shows 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 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 program-

ming time. Table 5, on page 25 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. 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.

Figure 3, on page 22 illustrates the algorithm for the program operation. See

Erase / Program Operations, on page 42 i for parameters, and Figure 17, on

page 43 for timing diagrams.

June 16, 2005 S29AL008D_00A3

S29AL008D

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