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P/N:PM0858 REV. 0.4, JUN. 07, 2002
MX28F320J3/640J3/128J3
BLOCK ERASE COMMAND
Automated block erase is initiated by writing the Block
Erase command of 20H followed by the Confirm com-
mand of D0H. An address within the block to be erased
is required (erase changes all block data to FFH).
Block preconditioning, erase, and verify are handled in-
ternally by the WSM (invisib le to the system). The CPU
can detect block erase completion by analyzing the out-
put of the STS pin or status register bit SR.7. Toggle OE,
CE0 , CE1 , or CE2 to update the status register. The
CUI remains in read status register mode until a new
command is issued. Also, reliable block erasure can only
occur when VCC is valid and VPEN = V PENH .
BLOCK ERASE SUSPEND COMMAND
This command only has meaning while the WSM is e x-
ecuting Block erase operation, and therefore will only be
responded to during Block erase operation. After this com-
mand has been e xecuted, the WSM suspend the erase
operations, and then return to Read Status Register
mode. The WSM will set the Q6 bit to a "1". Once the
WSM has reached the Suspend state, the WSM will set
WRITE TO BUFFER COMMAND
To program the device, a Write to Buffer command is
issue first. A variable number of bytes, up to the buffer
size, can be loaded into the buffer and written to the
flash device. First, the W r ite to Buffer Setup command
is issued along with the Block Address (see Figure ,
Write to Buffer Flowchart” on page ). After the com-
mand is issued, the extended Status Register (XSR) can
be read when CE is VIL. XSR.7 indicates if the Write
Buffer is available.
If the buffer is available, the number of words/bytes to
be program is written to the device. Next, the start ad-
dress is given along with the write buffer data. Subse-
quent writes provide additional device addresses and
data, depending on the count. After the last buffer data
is given, a Write Confirm command must be issued. The
WSM beginning cop y the buff er data to the flash arra y.
If an error occurs while writing, the device will stop writ-
ing, and status register bit SR.4 will be set to a "1" to
indicate a program f ailure. The internal WSM verify only
detects errors for "1" that do not successfully program
to "0" . If a program error is detected, the status register
should be cleared. Any time SR.4 and/or SR.5 is set, the
the Q7 bit to a "1". In default mode, STS will also transi-
tion to V OH.
At this time, A read array/program command sequence
can also be issued during erase suspend to read or pro-
gram data in other blocks. During a program operation
with block erase suspended, status register bit SR.7 will
return to "0" and STS output (in default mode) will transi-
tion to VOL The WSM will continue to r un, idling in the
SUSPEND state, regardless of the state of all input con-
trol pins.
The only other valid commands while block erase is sus-
pended are Read Query, Read Status Register, Clear
Status Register, Configure, and Block Erase Resume.
After a Block Erase Resume command is written to the
flash memory, the WSM will continue the block erase
process. Status register bits SR.6 and SR.7 will auto-
matically clear and STS (in default mode) will return to
VOL. VPEN must remain at VPENH (the same VPEN
level used for block erase) while block erase is suspended.
Block erase cannot resume until program operations ini-
tiated during block erase suspend have completed.
READ STATUS REGISTER COMMAND
The Status Register is read after writing the Read Status
Register command of 70H to the Command User Inter-
face. Also, after star ting the inter nal operation the de-
vice is set to the Read Status Register mode automati-
cally.
The contents of Status Register are latched on the later
falling edge of OE or the first edge of CE0, CE1, CE2
that enables the de vice OE must be toggle to VIH or the
device must be disable before further reads to update
the status register latch. The Read Status Register com-
mand functions independently of the VPEN v oltage.
CLEAR STATUS REGISTER COMMAND
The Erase Status, Program Status, Block Status bits
and protect status are set to "1" by the Write State Ma-
chine and can only be reset by the Clear Status Register
command of 50H. These bits indicates various failure
conditions.