AM29F160BT-90SEB View Datasheet(PDF) - Advanced Micro Devices

Part Name

Description

Manufacturer

AM29F160BT-90SEB

16 Megabit (2 M x 8-Bit/1 M x 16-Bit) CMOS 3.0 Volt-only Boot Sector Flash Memory

Advanced Micro Devices 

PRELIMINARY

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. (The RY/BY# pin is not availa-

ble on the 44-pin SO package.)

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 (including during

the Erase Suspend mode), or is in the standby mode.

Table 10 shows the outputs for RY/BY#. Figures 13, 14,

17 and 18 shows RY/BY# for read, reset, program, and

erase operations, respectively.

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, and is

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

command sequence (prior to the program or erase op-

eration), 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 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 sec-

tors, 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 the device is actively erasing (that

is, the Embedded Erase algorithm is in progress), DQ6

toggles. When the device 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 10 shows the outputs for Toggle Bit I on DQ6. Fig-

ure 6 shows the toggle bit algorithm in flowchart form,

and the section “Reading Toggle Bits DQ6/DQ2” ex-

plains the algorithm. Figure 20 in the “AC Characteris-

tics” section shows the toggle bit timing diagrams.

Figure 21 shows the differences between DQ2 and

DQ6 in graphical form. See also the subsection 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 eras-

ure. (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-suspended.

DQ6, by comparison, indicates whether the device is

actively erasing, or is in Erase Suspend, but cannot

distinguish which sectors are selected for erasure.

Thus, both status bits are required for sector and mode

information. Refer to Table 10 to compare outputs for

DQ2 and DQ6.

Figure 6 shows the toggle bit algorithm in flowchart

form, and the section “Reading Toggle Bits DQ6/DQ2”

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

subsection. Figure 20 shows the toggle bit timing dia-

gram. Figure 21 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 sta-

tus, 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 tog-

gle 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 completed the program or erase operation. The

system can read array data on DQ7–DQ0 on the fol-

lowing 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

complete the operation successfully, and the system

24

Am29LV160B

Share Link: