D a t a S h e e t ( P r e l i m i n a r y )
7.7
Program/Erase Operations
These devices are capable of several modes of programming and or erase operations which are described in
detail in the following sections.
During a write operation, the system must drive CE# and WE# to VIL and OE# to VIH when providing address,
command, and data. Addresses are latched on the last falling edge of WE# or CE#, while data is latched on
the 1st rising edge of WE# or CE#.
The Unlock Bypass feature allows the host system to send program commands to the Flash device without
first writing unlock cycles within the command sequence. See Section 7.7.8 for details on the Unlock Bypass
function.
Note the following:
When the Embedded Program algorithm is complete, the device returns to the read mode.
The system can determine the status of the program operation by reading the DQ status bits. Refer to the
Write Operation Status on page 36 for information on these status bits.
An “0” cannot be programmed back to a “1.” A succeeding read shows that the data is still “0.”
Only erase operations can convert a “0” to a “1.”
Any commands written to the device during the Embedded Program/Erase are ignored except the
Suspend commands.
Secured Silicon Sector, Autoselect, and CFI functions are unavailable when a program operation is in
progress.
A hardware reset and/or power removal immediately terminates the Program/Erase operation and the
Program/Erase command sequence should be reinitiated once the device has returned to the read mode
to ensure data integrity.
Programming is allowed in any sequence and across sector boundaries for single word programming
operation. See Write Buffer Programming on page 26 when using the write buffer.
Programming to the same word address multiple times without intervening erases is permitted.
7.7.1
Single Word Programming
Single word programming mode is one method of programming the Flash. In this mode, four Flash command
write cycles are used to program an individual Flash address. The data for this programming operation could
be 8 or 16-bits wide.
While the single word programming method is supported by most Spansion devices, in general Single Word
Programming is not recommended for devices that support Write Buffer Programming. See Table 12.1
on page 68 for the required bus cycles and Figure 7.1 for the flowchart.
When the Embedded Program algorithm is complete, the device then returns to the read mode and
addresses are no longer latched. The system can determine the status of the program operation by reading
the DQ status bits. Refer to Write Operation Status on page 36 for information on these status bits.
During programming, any command (except the Suspend Program command) is ignored.
The Secured Silicon Sector, Autoselect, and CFI functions are unavailable when a program operation is in
progress.
A hardware reset immediately terminates the program operation. The program command sequence should
be reinitiated once the device has returned to the read mode, to ensure data integrity.
Programming to the same address multiple times continuously (for example, “walking” a bit within a word)
is permitted.
24
S29GL-P MirrorBit® Flash Family
S29GL-P_00_A7 November 8, 2007
SPANSION [ SPANSION ]
