AMMCL00XA datasheet(19/36 Pages) AMD

19 / 36 page

AmMCL00XA

PRELIMIN ARY

able for read (note that in the Erase Suspend mode, the

Reset/Read command is not required for read opera-

tions and is ignored) or program operations in sectors

not being erased. Any other command written during

the Erase Suspend mode will be ignored, except for the

Erase Resume command. Writing the Erase Resume

command resumes the sector erase operation. The ad-

dresses are “don’t cares” when writing the Erase Sus-

pend or Erase Resume command.

When the Erase Suspend command is written during a

Sector Erase operation, the chip will take between 0.1

µs and 20 µs to actually suspend the operation and go

into erase suspended read mode (pseudo-read mode),

at which time the user can read or program from a sec-

tor that is not erase suspended. Reading data in this

mode is the same as reading from the standard read

mode, except that the data must be read from sectors

that have not been erase suspended.

Successively reading from the erase-suspended sec-

tor while the device is in the erase-suspend-read mode

will cause D2 to toggle. Polling D2 on successive reads

from a given sector provides the system the ability to

determine if a sector is in Erase Suspend.

After entering the erase-suspend-read mode, the user

can program the device by writing the appropriate com-

mand sequence for Byte Program. This program mode

is known as the erase suspend-program mode. Again,

programming in this mode is the same as programming

in the regular Byte Program mode, except that the data

must be programmed to sectors that are not erase sus-

pended. Successively reading from the erase sus-

pended sector while the device is in the erase

suspend-program mode will cause D2 to toggle. Com-

pletion of the erase suspend operation can be deter-

mined two ways:

s Checking the status of the toggle bit D2

s Checking the status of the RY/BY# pin

To resume the operation of Sector Erase, the Resume

command (30H) should be written. Any further writes of

the Resume command at this point will be ignored.

However, another Erase Suspend command can be

written after the device has resumed sector erase op-

erations.

Write Operation Status

Table 11 shows the status bit states for device program

and erase operations.

Data Polling—D7 (D15 on Odd Byte)

The Miniature card features DATA Polling as a method

to indicate to the host system that the embedded algo-

rithms are in progress or completed.

During the Embedded Program Algorithm, an attempt

to read the device will produce the compliment of the

data last written to D7. Upon completion of the Embed-

ded Program Algorithm, an attempt to read the device

will produce the true data last written to D7. Note that

just at the instant when D7 switches to true data, the

other bits, D6–D0, may not yet be true data. However,

they will all be true data on the next read from the de-

vice. Please note that Data Polling (D7) may give an

inaccurate result when an attempt is made to write

to a protected sector. During an Embedded Erase Al-

gorithm, an attempt to read the device will produce a ‘0’

at the D7 output. Upon completion of the Embedded

Er ase

Alg o r i th m,

at temp t

r ead

the device will produce a ‘1’ at D7.

Note: D7 is rechecked even if D5 = 1 because D7 may

change simultaneously with D5.

Figure 6.

Data Polling Algorithm

START

DQ7 = Data?

Yes

DQ5 = 1?

Yes

DQ7 = Data?

Yes

FAIL

PASS

21138E-7

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