AS29LV016D Datasheet, PDF (17/40 Pages) Micross Components – Superior inadvertent write protection

COTS PEM
BOOT SECTOR FLASH
AS29LV016
COMMAND DEFINITIONS
Writing specific address and data commands or
sequences into the command register initiates device
operations. Table 9 on page 21 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 CE#, whichever happens later. All data is latched
on the rising edge of WE# or CE#, whichever happens
first. Refer to the appropriate timing diagrams in AC
Characteristics on page 29.
READING ARRAY DATA
The device is automatically set to reading array data
after device power-up. No commands are required to
retrieve data. The device is also ready to read array data
after completing an Embedded Program or Embedded
Erase algorithm.
After the device accepts an Erase Suspend command,
the device enters the Erase Suspend mode. The system
can read array data using the standard read timings,
except that if it reads at an address within erase-
suspended sectors, the device outputs status data.
After completing a programming operation in the Erase
Suspend mode, the system may once again read array
data with the same exception. See Erase Suspend/Erase
Resume Commands on page 20 for more information
on this mode.
The system must issue the reset command to re-enable
the device for reading array data if DQ5 goes high, or
while in the autoselect mode. See Reset Command,
next.
See also Requirements for Reading Array Data on
page 7 for more information. The Read Operations on
page 29 provides the read parameters, and Figure 12,
on page 29 shows the timing diagram.
RESET COMMAND
Writing the reset command to the device resets the
device to reading array data. Address bits are don’t care
for this command.
Once erasure begins, however, the device ignores reset
commands until the operation is complete.
The reset command may be written between the
sequence cycles in a program command sequence
before programming begins. This resets the device to
reading array data (also applies to programming in Erase
Suspend mode). Once programming begins, however,
the device ignores reset commands until the operation
is complete.
The reset command may be written between the
sequence cycles in an autoselect command sequence.
Once in the autoselect mode, the reset command must
be written to return to reading array data (also applies
to autoselect during Erase Suspend).
If DQ5 goes high during a program or erase operation,
writing the reset command returns the device to reading
array data (also applies during Erase Suspend).
AUTOSELECT COMMAND SEQUENCE
The autoselect command sequence allows the host
system to access the manufacturer and devices codes,
and determine whether or not a sector is protected.
Table 9 on page 21 shows the address and data
requirements. This method is an alternative to that shown
in Table 4 on page 11, which is intended for PROM
programmers and requires V_ID on address bit A9.
The autoselect command sequence is initiated by writing
two unlock cycles, followed by the autoselect command.
The device then enters the autoselect mode, and the
system may read at any address any number of times,
without initiating another command sequence.
A read cycle at address XX00h retrieves the manufacturer
code. A read cycle at address XX01h returns the device
code. A read cycle containing a sector address (SA) and
the address 02h in word mode (or 04h in byte mode)
returns 01h if that sector is protected, or 00h if it is
unprotected. Refer to Table 2 on page 9 and Table 3 on
page 10 for valid sector addresses.
The system must write the reset command to exit the
The reset command may be written between the
sequence cycles in an erase command sequence before
AS29LV016
Rev. 2.2 01/10
17
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