AM29DL640G30PCEN datasheet(32/56 Pages) SPANSION

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Am29DL640G

June 6, 2005

RY/BY#: Ready/Busy#

The RY/BY# is a dedicated, open-drain output pin

which indicates whether an Embedded Algorithm is in

progress or complete. The RY/BY# status is valid after

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

sequence. Since RY/BY# is an open-drain output, sev-

eral RY/BY# pins can be tied together in parallel with a

pull-up resistor to V

CC.

If the output is low (Busy), the device is actively eras-

ing or programming. (This includes programming in

the Erase Suspend mode.) If the output is high

(Ready), the device is in the read mode, the standby

mode, or o ne of the ban ks is in the e rase-sus-

pend-read mode.

Table 13 shows the outputs for RY/BY#.

DQ6: Toggle Bit I

Toggle Bit I on DQ6 indicates whether an Embedded

Program or Erase algorithm is in progress or com-

plete, or whether the device has entered the Erase

Suspend mode. Toggle Bit I may be read at any ad-

dress, and is valid after the rising edge of the final

WE# pulse in the command sequence (prior to the

program or erase operation), and during the sector

erase time-out.

During an Embedded Program or Erase algorithm op-

eration, successive read cycles to any address cause

DQ6 to toggle. The system may use either OE# or

CE# to control the read cycles. When the operation is

complete, DQ6 stops toggling.

After an erase command sequence is written, if all

sectors selected for erasing are protected, DQ6 tog-

gles for approximately tASP µs, then returns to read-

ing array data. If not all selected sectors are protected,

the Embedded Erase algorithm erases the unpro-

tected sectors, and ignores the selected sectors that

are protected.

The system can use DQ6 and DQ2 together to deter-

min e whethe r a sector is actively e rasin g or is

erase-suspended. When the device is actively erasing

(that is, the Embedded Erase algorithm is in progress),

DQ6 toggles. When the device enters the Erase Sus-

pend mode, DQ6 stops toggling. However, the system

must also use DQ2 to determine which sectors are

erasing or erase-suspended. Alternatively, the system

can use DQ7 (see the subsection on DQ7: Data# Poll-

ing).

If a program address falls within a protected sector,

DQ6 toggles for approximately tPSP µs after the pro-

gram command sequence is written, then returns to

reading array data.

DQ6 also toggles during the erase-suspend-program

mode, and stops toggling once the Embedded Pro-

gram algorithm is complete.

Table 13 shows the outputs for Toggle Bit I on DQ6.

Figure 7 shows the toggle bit algorithm. Figure 23 in

the “AC Characteristics” section shows the toggle bit

timing diagrams. Figure 24 shows the differences be-

tween DQ2 and DQ6 in graphical form. See also the

subsection on DQ2: Toggle Bit II.

Figure 7.

Toggle Bit Algorithm

START

Yes

DQ5 = 1?

Yes

Toggle Bit

= Toggle?

Program/Erase

Operation Not

Complete, Write

Reset Command

Program/Erase

Operation Complete

Toggle Bit

= Toggle?

Read Byte Twice

(DQ7–DQ0)

Address = VA

Read Byte

(DQ7–DQ0)

Address =VA

Read Byte

(DQ7–DQ0)

Address =VA

Note: The system should recheck the toggle bit even if DQ5

= “1” because the toggle bit may stop toggling as DQ5

changes to “1.” See the subsections on DQ6 and DQ2 for

more information.

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