AM29LV640MH datasheet(37/62 Pages) AMD

37 / 62 page

December 14, 2005

Am29LV640MH/L

DA TA SH EET

WRITE OPERATION STATUS

The device provides several bits to determine the sta-

tus of a program or erase operation: DQ2, DQ3, DQ5,

DQ6, and DQ7. Table 12 and the following subsec-

tions describe the function of these bits. DQ7 and DQ6

each offer a method for determining whether a pro-

gram or erase operation is complete or in progress.

The device also provides a hardware-based output

signal, RY/BY#, to determine whether an Embedded

Program or Erase operation is in progress or has been

completed.

DQ7: Data# Polling

The Data# Polling bit, DQ7, indicates to the host sys-

tem whether an Embedded Program or Erase algo-

rithm is in progress or completed, or whether the

device is in Erase Suspend. Data# Polling is valid after

the rising edge of the final WE# pulse in the command

sequence.

During the Embedded Program algorithm, the device

outputs on DQ7 the complement of the datum pro-

grammed to DQ7. This DQ7 status also applies to pro-

g r amming dur i n g E r as e Su spe n d . Wh en t h e

Embedded Program algorithm is complete, the device

outputs the datum programmed to DQ7. The system

must provide the program address to read valid status

information on DQ7. If a program address falls within a

protected sector, Data# Polling on DQ7 is active for

approximately 1 µs, then the device returns to the read

mode.

During the Embedded Erase algorithm, Data# Polling

produces a “0” on DQ7. When the Embedded Erase

algorithm is complete, or if the device enters the Erase

Suspend mode, Data# Polling produces a “1” on DQ7.

The system must provide an address within any of the

sectors selected for erasure to read valid status infor-

mation on DQ7.

After an erase command sequence is written, if all

sectors selected for erasing are protected, Data# Poll-

ing on DQ7 is active for approximately 100 µs, then the

device returns to the read mode. If not all selected

sectors are protected, the Embedded Erase algorithm

erases the unprotected sectors, and ignores the se-

lected sectors that are protected. However, if the sys-

tem reads DQ7 at an address within a protected

sector, the status may not be valid.

Just prior to the completion of an Embedded Program

or Erase operation, DQ7 may change asynchronously

with DQ0–DQ6 while Output Enable (OE#) is asserted

low. That is, the device may change from providing

status information to valid data on DQ7. Depending on

when the system samples the DQ7 output, it may read

the status or valid data. Even if the device has com-

pleted the program or erase operation and DQ7 has

valid data, the data outputs on DQ0–DQ6 may be still

invalid. Valid data on DQ0–DQ7 will appear on suc-

cessive read cycles.

Table 12 shows the outputs for Data# Polling on DQ7.

Figure 8 shows the Data# Polling algorithm. Figure 20

in the AC Characteristics section shows the Data#

Polling timing diagram.

AM29LV640MH Datasheet(PDF) 37 Page - Advanced Micro Devices

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