EN29GL128H-70BAIP EON [Eon Silicon Solution Inc.], EN29GL128H-70BAIP Datasheet - Page 26

• Manufacturer Part Number: EN29GL128H-70BAIP
• Description: 128 Megabit (16384K x 8-bit / 8192K x 16-bit) Flash Memory Page mode Flash Memory, CMOS 3.0 Volt-only
• Manufacturer: EON [Eon Silicon Solution Inc.]

Dynamic Protection Bits
Dynamic Protection Bits are volatile and unique for each sector and can be individually modified. DYBs
only control the protection scheme for unprotected sectors that have their PPBs cleared (erased to “1”).
By issuing the DYB Set or Clear command sequences, the DYBs are set (programmed to “0”) or
cleared (erased to “1”), thus placing each sector in the protected or unprotected state respectively. This
feature allows software to easily protect sectors against inadvertent changes yet does not prevent the
easy removal of protection when changes are needed.
Notes
1. The DYBs can be set (programmed to “0”) or cleared (erased to “1”) as often as needed. When the
2. If the option to clear the DYBs after power up is chosen, (erased to “1”), then the sectorsmay be
3. The sectors would be in the protected state If the option to set the DYBs after power up is chosen
4. It is possible to have sectors that are persistently locked with sectors that are left in the dynamic
5. The DYB Set or Clear commands for the dynamic sectors signify protected or unprotected state of
6. To achieve the best protection, it is recommended to execute the PPB Lock Bit Set command early
Persistent Protection Bit Lock Bit
The Persistent Protection Bit Lock Bit is a global volatile bit for all sectors. When set (programmed to
“0”), it locks all PPBs and when cleared (erased to “1”), allows the PPBs to be changed. There is only
one PPB Lock Bit per device.
Notes
1. No software command sequence unlocks this bit, but only a hardware reset or a power-up clears this
2. The PPB Lock Bit must be set (programmed to “0”) only after all PPBs are configured to the desired
This Data Sheet may be revised by subsequent versions
or modifications due to changes in technical specifications.
parts are first shipped, the PPBs are cleared (erased to “1”) and upon power up or reset, the DYBs
can be set or cleared depending upon the ordering option chosen.
modified depending upon the PPB state of that sector (see Table 7).
(programmed to “0”).
state.
the sectors respectively. However, if there is a need to change the status of the persistently locked
sectors, a few more steps are required. First, the PPB Lock Bit must be cleared by either putting the
device through a power-cycle, or hardware reset. The PPBs can then be changed to reflect the
desired settings. Setting the PPB Lock Bit once again locks the PPBs, and the device operates
normally again.
in the boot code and protect the boot code by holding WP#/ACC = VIL. Note that the PPB and DYB
bits have the same function when WP#/ACC = VHH as they do when ACC =VIH.
bit.
settings.
Rev. H, Issue Date: 2009/10/01
26
©2004 Eon Silicon Solution, Inc.,
EN29GL128H/L
www.eonssi.com