AM29LV128ML93RPCI datasheet(29/65 Pages) AMD

29 / 65 page

September 9, 2003

Am29LV128MH/L

DA T A SH EET

COMMAND DEFINITIONS

Writing specific address and data commands or se-

quences into the command register initiates device op-

erations. Tables 10 and 11 defines the valid register

command sequences.

Writing incorrect address and

data values or writing them in the improper sequence

may place the device in an unknown state. A reset

command is then required to return the device to read-

ing 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

w h ic h t he s y s t em c an read dat a f r om 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 14 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).

Note that if DQ1 goes high during a Write Buffer Pro-

gramming operation, the system must write the

Write-to-Buffer-Abort Reset command sequence to

reset the device for the next operation.

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.

Tables 10 and 11 show the address and data require-

ments. This method is an alternative to that shown in

Table 3, which is intended for PROM programmers

and requires V

ID on address pin A9. The autoselect

command 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 first

writing two unlock cycles. This is followed by a third

write cycle that contains the autoselect command. The

device then enters the autoselect mode. The system

may read at any address any number of times without

initiating another autoselect command sequence:

■ A read cycle at address XX00h returns the manu-

facturer code.

■ Three read cycles at addresses 01h, 0Eh, and 0Fh

return the device code.

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

dress (SA), and the address 02h on A7–A0 in word

mode returns 01h if the sector is protected, or 00h if

it is unprotected.

The system must write the reset command to return to

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

vice was previously in Erase Suspend).

AM29LV128ML93RPCI Datasheet(PDF) 29 Page - Advanced Micro Devices

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