AM29DL800B View Datasheet(PDF) - Advanced Micro Devices

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AM29DL800B

8 Megabit (1 M x 8-Bit/512 K x 16-Bit) CMOS 3.0 Volt-only, Simultaneous Operation Flash Memory

Advanced Micro Devices 

DATA SHEET

RY/BY#: Ready/Busy#

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

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 VCC.

If the output is low (Busy), the device is actively erasing

or programming. (This includes programming in the

Erase Suspend mode.) If the output is high (Ready),

the device is ready to read array data, is in the standby

mode, or one of the banks is in the erase-suspend-read

mode.

Table 6 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 complete,

or whether the device has entered the Erase Suspend

mode. Toggle Bit I may be read at any address within

the programming or erasing bank, and is valid after the

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

quence (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 within

the programming or erasing bank 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 sec-

tors selected for erasing are protected, DQ6 toggles for

approximately 100 µs, then returns to reading array

data. If not all selected sectors are protected, the Em-

bedded Erase algorithm erases the unprotected

sectors, and ignores the selected sectors that are

protected.

The system can use DQ6 and DQ2 together to deter-

mine whether a sector is actively erasing or is erase-

suspended. When a bank is actively erasing (that is,

the Embedded Erase algorithm is in progress), DQ6

toggles. When that bank enters the Erase Suspend

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 6 shows the outputs for Toggle Bit I on DQ6. Fig-

ure 6 shows the toggle bit algorithm. Figure 21 in the

“AC Characteristics” section shows the toggle bit timing

diagrams. Figure 22 shows the differences between

DQ2 and DQ6 in graphical form. See also the subsec-

tion on DQ2: Toggle Bit II.

DQ2: Toggle Bit II

The “Toggle Bit II” on DQ2, when used with DQ6, indi-

cates whether a particular sector is actively erasing

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

or whether that sector is erase-suspended. Toggle Bit

II is valid after the rising edge of the final WE# pulse in

the command sequence.

DQ2 toggles when the system reads at addresses

within those sectors that have been selected for era-

sure. (The system may use either OE# or CE# to

control the read cycles.) But DQ2 cannot distinguish

whether the sector is actively erasing or is erase-sus-

pended. DQ6, by comparison, indicates whether the

device is actively erasing, or is in Erase Suspend, but

cannot distinguish which sectors are selected for era-

sure. Thus, both status bits are required for sector and

mode information. Refer to Table 6 to compare outputs

for DQ2 and DQ6.

Figure 6 shows the toggle bit algorithm in flowchart

form, and the section “DQ2: Toggle Bit II” explains the

algorithm. See also the DQ6: Toggle Bit I subsection.

Figure 21 shows the toggle bit timing diagram. Figure

22 shows the differences between DQ2 and DQ6 in

graphical form.

Reading Toggle Bits DQ6/DQ2

Refer to Figure 6 for the following discussion. When-

ever the system initially begins reading toggle bit

status, it must read DQ7–DQ0 at least twice in a row to

determine whether a toggle bit is toggling. Typically, the

system would note and store the value of the toggle bit

after the first read. After the second read, the system

would compare the new value of the toggle bit with the

first. If the toggle bit is not toggling, the device has com-

pleted the program or erase operation. The system can

read array data on DQ7–DQ0 on the following read

cycle.

However, if after the initial two read cycles, the system

determines that the toggle bit is still toggling, the sys-

tem also should note whether the value of DQ5 is high

(see the section on DQ5). If it is, the system should

then determine again whether the toggle bit is toggling,

since the toggle bit may have stopped toggling just as

DQ5 went high. If the toggle bit is no longer toggling,

the device has successfully completed the program or

erase operation. If it is still toggling, the device did not

completed the operation successfully, and the system

must write the reset command to return to reading

array data.

22

Am29DL800B

21519C4 December 4, 2006

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