32Mb, 64Mb, 128Mb: 3V Embedded Parallel NOR Flash
Program Operations
is long, considerable time savings can be gained by using these commands. When in
unlock bypass mode, only the following commands are valid:
• The UNLOCK BYPASS PROGRAM command can be issued to program addresses
within the device.
• The UNLOCK BYPASS BLOCK ERASE command can then be issued to erase one or
more memory blocks.
• The UNLOCK BYPASS CHIP ERASE command can be issued to erase the whole mem-
ory array.
• The UNLOCK BYPASS WRITE TO BUFFER PROGRAM and UNLOCK BYPASS EN-
HANCED WRITE TO BUFFER PROGRAM commands can be issued to speed up the
programming operation.
• The UNLOCK BYPASS RESET command can be issued to return the device to read
mode.
In unlock bypass mode, the device can be read as if in read mode.
In addition to the UNLOCK BYPASS command, when VPP/WP# is raised to VPPH, the de-
vice automatically enters unlock bypass mode. When VPP/WP# returns to VIH or VIL, the
device is no longer in unlock bypass mode and normal operation resumes. The transi-
tions from VIH to VPPH and from VPPH to VIH must be slower than tVHVPP (see the Accel-
erated Program, Data Polling/Toggle AC Characteristics).
Note: Micron recommends the user enter and exit unlock bypass mode using ENTER
UNLOCK BYPASS and UNLOCK BYPASS RESET commands rather than raising VPP/WP#
to VPPH. VPP/WP# should never be raised to VPPH from any mode except read mode; oth-
erwise, the device may be left in an indeterminate state.
UNLOCK BYPASS RESET Command
The UNLOCK BYPASS RESET (90/00h) command is used to return to read/reset mode
from unlock bypass mode. Two bus WRITE operations are required to issue the UN-
LOCK BYPASS RESET command. The READ/RESET command does not exit from un-
lock bypass mode.
Program Operations
PROGRAM Command
The PROGRAM (A0h) command can be used to program a value to one address in the
memory array. The command requires four bus WRITE operations, and the final WRITE
operation latches the address and data in the internal state machine and starts the pro-
gram/erase controller. After programming has started, bus READ operations output the
status register content.
Programming can be suspended and then resumed by issuing a PROGRAM SUSPEND
command and a PROGRAM RESUME command, respectively.
If the address falls in a protected block, the PROGRAM command is ignored, and the
data remains unchanged. The status register is not read, and no error condition is given.
After the PROGRAM operation has completed, the device returns to read mode, unless
an error has occurred. When an error occurs, bus READ operations to the device contin-
PDF: 09005aef84dc44a7
m29ew_32Mb-128Mb.pdf - Rev. B 11/12 EN
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36
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