AM29PDS322D datasheet(23/51 Pages) SPANSION

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December 4, 2006 23569A5

Am29PDS322D

D A TA

SH EET

writes are ignored until V

CC is greater than VLKO. The

system must provide the proper signals to the control

pins to prevent unintentional writes when V

CC is

greater than V

LKO.

Write Pulse “Glitch” Protection

Noise pulses of less than 5 ns (typical) on OE#, CE#

or WE# do not initiate a write cycle.

Logical Inhibit

Write cycles are inhibited by holding any one of OE# =

IL, CE# = VIH or WE# = VIH. To initiate a write cycle,

CE# and WE# must be a logical zero while OE# is a

logical one.

Power-Up Write Inhibit

If WE# = CE# = V

IL and OE# = VIH during power up,

the device does not accept commands on the rising

edge of WE#. The internal state machine is automati-

cally reset to the read mode on power-up.

COMMAND DEFINITIONS

Writing specific address and data commands or se-

quences into the command register initiates device op-

erations. Table 10 defines the valid register command

sequences. Writing incorrect address and data val-

ues 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 AC Characteristics section for timing

diagrams.

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 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-read mode, after

which the system can read data from an y

non-erase-suspended sector. After completing a pro-

gramming operation in the Erase Suspend mode, the

system may once again read array data with the same

exception. See the Erase Suspend/Erase Resume

Commands section for more information.

The system must issue the reset command to return

the device to the read (or erase-suspend-read) mode if

DQ5 goes high during an active program or erase op-

eration, or if the device is in the autoselect mode. See

the next section, Reset Command, for more informa-

tion.

See also Requirements for Reading Array Data in the

Device Bus Operations section for more information.

The Read-Only Operations table provides the read pa-

rameters, and Figure 15 shows the timing diagram.

Reset Command

Writing the reset command resets the device to the

read or erase-suspend-read mode. Address bits are

don’t cares for this command.

The reset command may be written between the se-

quence cycles in an erase command sequence before

erasing begins. This resets the device to the read

mode. Once erasure begins, however, the device ig-

nores 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

the read mode. If the program command sequence is

written while the device is in the Erase Suspend mode,

writing the reset command returns the device to the

erase-suspend-read mode. Once programming be-

gins, however, the device ignores reset commands

until the operation is complete.

The reset command may be written between the se-

quence cycles in an autoselect command sequence.

Once in the autoselect mode, the reset command

must be written to return to the read mode. If the de-

vice entered the autoselect mode while in the Erase

Suspend mode, writing the reset command returns the

device to the erase-suspend-read mode.

If DQ5 goes high during a program or erase operation,

writing the reset command returns the device to the

read mode (or erase-suspend-read mode if the device

was in Erase Suspend).

Autoselect Command Sequence

The autoselect command sequence allows the host

system to access the manufacturer and device codes,

and determine whether or not a sector is protected.

Table 10 shows the address and data requirements.

This method is an alternative to that shown in Table 7,

which is intended for PROM programmers and re-

quires V

ID on address pin A9. The autoselect com-

mand sequence may be written to an address that is

either in the read or erase-suspend-read mode. The

autoselect command may not be written while the de-

vice is actively programming or erasing.

The autoselect command sequence is initiated by writ-

ing two unlock cycles, followed by the autoselect

command. The device then enters the autoselect mode,

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