28F640L30, 28F128L30, 28F256L30
3.1.4
Standby
When CE# is deasserted the device is deselected and placed in standby, substantially reducing
power consumption. In standby, the data outputs are placed in High-Z, independent of the level
placed on OE#. Standby current, ICCS, is the average current measured over any 5 ms time interval,
5 µs after CE# is deasserted. During standby, average current is measured over the same time
interval 5 µs after CE# is deasserted.
When the device is deselected (while CE# is deasserted) during a program or erase operation, it
continues to consume active power until the program or erase operation is completed.
3.1.5
Reset
As with any automated device, it is important to assert RST# when the system is reset. When the
system comes out of reset, the system processor attempts to read from the flash memory if it is the
system boot device. If a CPU reset occurs with no flash memory reset, improper CPU initialization
may occur because the flash memory may be providing status information rather than array data.
Intel® flash memory devices allow proper CPU initialization following a system reset through the
use of the RST# input. RST# should be controlled by the same low-true reset signal that resets the
system CPU.
After initial power-up or reset, the device defaults to asynchronous Read Array, and the Status
Register is set to 0x80. Asserting RST# de-energizes all internal circuits, and places the output
drivers in High-Z. When RST# is asserted, the device shuts down the operation in progress, a
process which takes a minimum amount of time to complete. When RST# has been deasserted, the
device is reset to asynchronous Read Array state.
Note: If RST# is asserted during a program or erase operation, the operation is terminated and the
memory contents at the aborted location (for a program) or block (for an erase) are no longer valid,
because the data may have been only partially written or erased.
When returning from a reset (RST# deasserted), a minimum wait is required before the initial read
access outputs valid data. Also, a minimum delay is required after a reset before a write cycle can
be initiated. After this wake-up interval passes, normal operation is restored. See Section 12.0, “AC
Characteristics” on page 55 for details about signal-timing.
3.2
Device Commands
Device operations are initiated by writing specific device commands to the Command User
Interface (CUI). See Table 5, “Command Bus Cycles” on page 19.
Several commands are used to modify array data including Word Program and Block Erase
commands. Writing either command to the CUI initiates a sequence of internally-timed functions
that culminate in the completion of the requested task. However, the operation can be aborted by
either asserting RST# or by issuing an appropriate suspend command.
18
Datasheet
INTEL [ INTEL ]
