AM29DL16XD datasheet(31/57 Pages) AMD

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May 26, 2004

Am29DL16xD

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 reading array data, the standby

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

pend-read mode.

Table 15 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 100 µs, then returns to reading

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

Embedded Erase algorithm erases the unprotected

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#

Polling).

If a program address falls within a protected sector,

DQ6 toggles for approximately 1

µs after the program

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 15 shows the outputs for Toggle Bit I on DQ6.

Figure 6 shows the toggle bit algorithm. Figure 22 in

the “AC Characteristics” section shows the toggle bit

timing diagrams. Figure 23 shows the differences be-

tween DQ2 and DQ6 in graphical form. See also the

subsection on DQ2: Toggle Bit II.

START

Yes

DQ5 = 1?

Yes

Toggle Bit

= Toggle?

Program/Erase

Operation Not

Complete, Write

Reset Command

Program/Erase

Operation Complete

Read DQ7–DQ0

Toggle Bit

= Toggle?

Read DQ7–DQ0

Twice

Read DQ7–DQ0

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.

Figure 6.

Toggle Bit Algorithm

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