EN29LV320
Write Protect / Accelerated Program (WP# / ACC)
The WP#/ACC pin provides two functions. The Write Protect (WP#) function provides a hardware method
of protecting the outermost two 8K-byte Boot Sector. The ACC function allows faster manufacturing
throughput at the factory, using an external high voltage.
When WP#/ACC is Low, the device protects the outermost tw 8K-byte Boot Sector; no matter the sectors
are protected or unprotected using the method described in “Sector/Sector Group Protection & Chip
Unprotection”, Program and Erase operations in these sectors are ignored.
When WP#/ACC is High, the device reverts to the previous protection status of the outermost two 8K-byte
boot sector. Program and Erase operations can now modify the data in the two outermost 8K-byte Boot
Sector unless the sector is protected using Sector Protection.
When WP#/ACC is raised to VHH the memory automatically enters the Unlock Bypass mode(please refer
to “Command Definitions”), temporarily unprotects every protected sectors, and reduces the time required
for program operation. The system would use a two-cycle program command sequence as required by
the Unlock Bypass mode. When WP#/ACC returns to VIH or VIL, normal operation resumes. The
transitions from VIH or VIL to VHH and from VHH to VIH or VIL must be slower than tVHH, see Figure 11.
Note that the WP#/ACC pin must not be left floating or unconnected. In addition, WP#/ACC pin must not
be at VHH for operations other than accelerated programming. It could cause the device to be damaged.
Never raise this pin to VHH from any mode except Read mode, otherwise the memory may be left in an
indeterminate state.
A 0.1µF capacitor should be connected between the WP#/ACC pin and the VSS Ground pin to decouple
the current surges from the power supply. The PCB track widths must be sufficient to carry the currents
required during Unlock Bypass Program.
Temporary Sector Unprotect
Start
This feature allows temporary unprotection of previously protected
sector groups to change data while in-system. The Temporary
Sector Unprotect mode is activated by setting the RESET# pin to
VBIDB. During this mode, formerly protected sectors can be
programmed or erased by simply selecting the sector addresses.
Once VBIDB is removed from the RESET# pin, all the previously
Reset#=VID (note 1)
Perform Erase or Program
Operations
protected sectors are protected again.
flowchart and figure 10 for more timing details.
See accompanying
RESET#=VIH
Temporary Sector Unprotect
Completed (note 2)
Notes:
1. All protected sectors are unprotected. (If
WP#/ACC=VIL, outermost boot sectors will remain
protected.)
2. Previously protected sectors are protected again.
COMMON FLASH INTERFACE (CFI)
The common flash interface (CFI) specification outlines device and host systems software
interrogation handshake, which allows specific vendor-specified software algorithms to be used for
entire families of devices. Software support can then be device-independent, JEDEC ID-
independent, and forward- and backward-compatible for the specified flash device families. Flash
vendors can standardize their existing interfaces for long-term compatibility.
This Data Sheet may be revised by subsequent versions
or modifications due to changes in technical specifications.
©2004 Eon Silicon Solution, Inc., www.essi.com.tw
15
Rev. E, Issue Date: 2006/05/16
EON [ EON SILICON SOLUTION INC. ]
