W78M32VP-XBX
The Autoselect command may not be written while the
READ
device is actively programming or erasing.
All memories require access time to output array data. In a read
operation, data is read from one memory location at a time.
Addresses are presented to the device in random order, and the
propagation delay through the device causes the data on its outputs
to arrive with the address on its inputs.
The system must write the reset command to return to the
read mode (or erase-suspend-read mode if the sector was
previously in Erase Suspend).
It is recommended that A9 apply VID after power-up
sequence is completed. In addition, it is recommended that
A9 apply from VID to VIH/VIL before power-down the VCC/VIO.
The device defaults to reading array data after device power-up or
hardware reset. To read data from the memory array, the system
must first assert a valid address onA22-A0, while driving OE# and
CE# to VIL. WE# must remain at VIH. All addresses are latched
on the falling edge of CE#. Data will appear on DQ15-DQ0 after
address access time (tACC), which is equal to the delay from stable
addresses to valid output data.
See Table 39 for command sequence details.
When verifying sector protection, the sector address
must appear on the appropriate highest order address
bits (see Table 5 to Table 6). The remaining address bits
are don't care. When all necessary bits have been set
as required, the programming equipment may then read
the corresponding identifier code on DQ15-DQ0. The
Autoselect codes can also be accessed in-system through
the command register.
The OE# signal must be driven to VIL. Data is output on DQ15-DQ0
pins after the access time (tOE) has
elapsed from the falling edge of OE#, assuming the tACC access
time has been meet.
PROGRAM/ERASE OPERATIONS
PAGE READ MODE
These devices are capable of several modes of programming and
or erase operations which are described in detail in the following
sections.
The device is capable of fast page mode read and is compatible
with the page mode Mask ROM read operation. This mode provides
faster read access speed for random locations within a page. The
page size of the device is 8 words. The appropriate page is selected
by the higher address bits A(22)-A3.
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#.
Address bits A2-A0 in word mode determine the specific word
within a page. The microprocessor supplies the specific word
location. The random or initial page access is equal to tACC or tCE
and subsequent page read accesses (as long as the locations
specified by the microprocessor falls within that page) is equivalent
to tPACC. When CE# is deasserted and reasserted for a subsequent
access, the access time is tACC or tCE. Fast page mode accesses
are obtained by keeping the “read-page addresses” constant and
changing the “intra-read page” addresses.
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 Unlock Bypass section for
details on the Unlock Bypass function.
Note the following:
When the Embedded Program algorithm is complete, the
device returns to the read mode.
AUTOSELECT
The system can determine the status of the program
operation by reading the DQ status bits. Refer to the Write
Operation Status for information on these status bits.
The Autoselect mode provides manufacturer ID, Device
identification, and sector protection information, through identifier
codes output from the internal register (separate from the
memory array) on DQ7-DQ0. This mode is primarily intended for
programming equipment to automatically match a device to be
programmed with its corresponding programming algorithm (see
Table 4). The Autoselect codes can also be accessed in-system.
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.
There are two methods to access autoselect codes. One uses
the autoselect command, the other applies VID on address pin A9.
Secured Silicon Sector, Autoselect, and CFI functions are
When using programming equipment, the autoselect mode requires
VID (11.5 V to 12.5 V) on address pin A9. Address pins must be
as shown in Table 3.
unavailable when a program operation is in progress.
A hardware reset and/or power removal immediately
terminates the Program/Erase operation and the
To access Autoselect mode without using high voltage on
Program/Erase command sequence should be reinitiated
once the device has returned to the read mode to ensure
data integrity.
A9, the host system must issue the Autoselect command.
The Autoselect command sequence may be written to an
address within a sector that is either in the read or erase-
suspend-read mode.
Programming is allowed in any sequence and across sector
boundaries for single word programming operation. See
Write Buffer Programming when using the write buffer.
Microsemi Corporation reserves the right to change products or specifications without notice.
August 2011 © 2011 Microsemi Corporation. All rights reserved.
Rev. 15
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