AM29DL322D datasheet(24/54 Pages) AMD

24 / 54 page

June 10, 2003

Am29DL322D/323D/324D

again read array data with the same exception. See

the Erase Suspend/Erase Resume Commands sec-

tion for more information.

The system must issue the reset command to return a

bank to the read (or erase-suspend-read) mode if DQ5

goes high during an active program or erase opera-

tion, or if the bank is in the autoselect mode. See the

next section, Reset Command, for more information.

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 13 shows the timing diagram.

Reset Command

Writing the reset command resets the banks 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 bank to which the sys-

tem was writing to the read mode. Once erasure be-

gins, 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 bank to

which the system was writing to the read mode. If the

program command sequence is written to a bank that

is in the Erase Suspend mode, writing the reset

command returns tha t b ank to the e r ase-sus-

pend-read mode. Once programming begins, how-

ever, 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 a bank

entered the autoselect mode while in the Erase Sus-

pend mode, writing the reset command returns that

bank to the erase-suspend-read mode.

If DQ5 goes high during a program or erase operation,

writing the reset command returns the banks to the

read mode (or erase-suspend-read mode if that bank

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 14 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 VID on address pin A9. The autoselect com-

mand sequence may be written to an address within a

bank that is either in the read or erase-suspend-read

mode. The autoselect command may not be written

while the device is actively programming or erasing in

the other bank.

The autoselect command sequence is initiated by first

writing two unlock cycles. This is followed by a third

write cycle that contains the bank address and the au-

toselect command. The bank then enters the autose-

lect mode. The system may read at any address within

the same bank any number of times without initiating

another autoselect command sequence:

■ A read cycle at address (BA)XX00h (where BA is

the bank address) returns the manufacturer code.

■ A read cycle at address (BA)XX01h in word mode

(or (BA)XX02h in byte mode) returns the device

code.

■ A read cycle to an address containing a sector ad-

dress (SA) within the same bank, and the address

02h on A7–A0 in word mode (or the address 04h on

A6–A-1 in byte mode) returns 01h if the sector is

protected, or 00h if it is unprotected. (Refer to Ta-

bles 3–6 for valid sector addresses).

The system must write the reset command to return to

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

bank was previously in Erase Suspend).

Enter SecSi

 Sector/Exit SecSi Sector

Command Sequence

The SecSi Sector region provides a secured data area

containing a random, sixteen-byte electronic serial

number (ESN). The system can access the SecSi

Sector region by issuing the three-cycle Enter SecSi

Sector command sequence. The device continues to

access the SecSi Sector region until the system is-

sues the four-cycle Exit SecSi Sector command se-

quence. The Exit SecSi Sector command sequence

returns the device to normal operation. The SecSi

Sector is not accessible when the device is executing

an Embedded Program or Embedded Erase algo-

rithm. Table 14 shows the address and data require-

ments for both command sequences. See also “SecSi



(Secured Silicon) Sector Flash Memory Region” for fur-

ther information.

Byte/Word Program Command Sequence

The system may program the device by word or byte,

depending on the state of the BYTE# pin. Program-

ming is a four-bus-cycle operation. The program com-

mand sequence is initiated by writing two unlock write

cycles, followed by the program set-up command. The

program address and data are written next, which in

turn initiate the Embedded Program algorithm. The

system is not required to provide further controls or

timings. The device automatically provides internally

generated program pulses and verifies the pro-

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