EFST
preliminary
F49L004UA / F49L004BA
Figure 16 shows the algorithms and Figure 15 shows
the timing diagram. This method uses standard
microprocessor bus cycle timing. For sector unprotect,
all unprotected sectors must first be protected prior to
the first sector unprotect write cycle.
Output Disable Mode
With the
is at a logic high level (VIH), outputs from
OE
the devices are disabled. This will cause the output pins
in a high impedance state
The alternate method intended only for programming
equipment requires VID on address pin A9,
RESET
, and
OE
Standby Mode
.
When
and
are both held at VCC ± 0.3V,
RESET
CE
the device enter CMOS Standby mode. If
and
CE
Auto-select Mode
are held at VIH, but not within the range of VCC
RESET
The auto-select mode provides manufacturer and
device identification and sector protection verification,
through outputs on DQ7–DQ0. This mode is primarily
intended for programming equipment to automatically
± 0.3V, the device will still be in the standby mode, but
the standby current will be larger.
If the device is deselected during auto algorithm of
erasure or programming, the device draws active
current ICC2 until the operation is completed. ICC3 in the
DC Characteristics table represents the standby current
specification.
match
a
device to be programmed with its
corresponding programming algorithm. However, the
auto-select codes can also be accessed in-system
through the command register.
When using programming equipment, this mode
The device requires standard access time (tCE) for read
access from either of these standby modes, before it is
ready to read data.
requires VID (11.5 V to 12.5 V) on address pin A9. While
address pins A3, A2, A1, and A0 must be as shown in
Table 4.
To verify sector protection, all necessary pins have to
be set as required in Table 4, the programming
equipment may then read the corresponding identifier
code on DQ7-DQ0.
Sector Protect / Un-protect Mode
The hardware sector protect feature disables both
program and erase operations in any sector. The
hardware sector unprotect feature re-enables both the
program and erase operations in previously protected
sectors. Sector protect/unprotect can be implemented
via two methods.
The primary method requires VID on the
only, and can be implemented either in-system or via
programming equipment.
To access the auto-select codes in-system, the host
system can issue the auto-select command via the
command register, as shown in Table 5. This method
does not require VID. See “ Software Command
pin
Definitions” for details on using the auto-select mode.
RESET
7.2 Software Command Definitions
Writing specific address and data commands or
sequences into the command register initiates the
device operations. Table 5 defines the valid register
command sequences. Writing incorrect address and
data values or writing them in the improper sequence
resets the device to reading array data.
All addresses are latched on the falling edge of
WE
or
, whichever happens later. All data is latched on
CE
the rising edge of
or
, whichever happens
WE
CE
first. Refer to the corresponding timing diagrams in the
AC Characteristics section.
Elite Flash Storage Technology Inc.
Publication Date : Aug. 2003
Revision: 0.2
9/46
ESMT [ ELITE SEMICONDUCTOR MEMORY TECHNOLOGY INC. ]
