EN29GL256H Datasheet, PDF (26/57 Pages) Eon Silicon Solution Inc. – 256 Megabit (32768K x 8-bit / 16384K x 16-bit) Flash Memory Page mode Flash Memory, CMOS 3.0 Volt-only

EN29GL256H/L
Advanced Sector Protection/Unprotection
The Advanced Sector Protection/Unprotection feature disables or enables programming or erase
operations in any or all sectors and can be implemented through software and/or hardware methods,
which are independent of each other. This section describes the various methods of protecting data
stored in the memory array. An overview of these methods in shown in Figure 7.
Figure 7. Advanced Sector Protection/Unprotection
Dynamic Protection Bit
(DYB)
Memory Array
Persistent Protection
Bit (PPB)
DYB 0
DYB 1
DYB 2
DYB 3
DYB 4
DYB 5
DYB 6
DYB 7
Sector 0
Sector 1
Sector 2
Sector 3
Sector 4
Sector 5
Sector 6
Sector 7
PPB 0
PPB 1
PPB 2
PPB 3
PPB 4
PPB Lock Bit
1. 0 = PPBs Locked,
1 = PPBs Unlocked.
2. Bit is volatile, and defaults to
“1” on reset.
3. Programming to “0” locks all
PPBs to their current state.
4. Once programmed to “0”,
requires hardware reset to
unlock.
DYB 248
DYB 249
DYB 250
DYB 251
DYB 252
DYB 253
DYB 254
DYB 255
5. 0 = Sector Protected,
1 = Sector Unprotected.
6. DYB bits are only effective for
sectors that not protected via
PPB locking mechanism.
7. Volatile Bits: defaults to
unprotected after power up.
Sector 248
Sector 249
Sector 250
Sector 251
Sector 252
Sector 253
Sector 254
Sector 255
PPB 65
PPB 66
PPB 67
PPB 68
PPB 69
8. 0 = Sector Protected,
1 = Sector Unprotected.
9. PPBs programmed individually,
but cleared collectively.
10.Sector 0~3 and 252~255 have
PPB for each sector. Sector
4~251 are 1 PPB per 4 sectors.
Lock Register
The Lock Register consists of 4 bits. The Secured Silicon Sector Protection Bit is DQ0, Persistent
Protection Mode Lock Bit is DQ1, Persistent Sector Protection OTP bit is DQ3 and DYB Lock Boot Bit is
DQ4. If DQ0 is ‘0’, it means that the Customer Secured Silicon area is locked and if DQ0 is ‘1’, it means
that it is unlocked. When DQ1 is set to ‘0’, the device is used in the Persistent Protection Mode. DQ3 is
programmed in the EON factory. When the device is programmed to disable all PPB erase command,
DQ3 outputs a ‘0’, when the lock register bits are read. Similarly, if the device is programmed to enable
This Data Sheet may be revised by subsequent versions
26
or modifications due to changes in technical specifications.
©2004 Eon Silicon Solution, Inc.,
Rev. G, Issue Date: 2011/01/17
www.eonssi.com