EN25LF20
BP2, BP1, BP0 bits.
The Block Protect (BP2, BP1, BP0) bits are non-volatile. They define the size of
the area to be software protected against Program and Erase instructions.
SRP bit / OTP_LOCK bit
The Status Register Protect (SRP) bit is operated in conjunction with the
Write Protect (WP#) signal. The Status Register Protect (SRP) bit and Write Protect (WP#) signal allow
the device to be put in the Hardware Protected mode. In this mode, the non-volatile bits of the Status
Register (SRP, BP2, BP1, BP0) become read-only bits.
In OTP mode, this bit is served as OTP_LOCK bit, user can read/program/erase OTP sector as normal
sector while OTP_LOCK value is equal 0, after OTP_LOCK is programmed with 1 by WRSR command,
the OTP sector is protected from program and erase operation. The OTP_LOCK bit can only be
programmed once.
Note :
In OTP mode, the WRSR command will ignore any input data and program OTP_LOCK bit to 1,
user must clear the protect bits before enter OTP mode and program the OTP code, then execute
WRSR command to lock the OTP sector before leaving OTP mode.
Write Protection
Applications that use non-volatile memory must take into consideration the possibility of noise and other
adverse system conditions that may compromise data integrity. To address this concern the EN25LF20
provides the following data protection mechanisms:
Power-On Reset and an internal timer (tPUW ) can provide protection against inadvertent changes
while the power supply is outside the operating specification.
Program, Erase and Write Status Register instructions are checked that they consist of a number
of clock pulses that is a multiple of eight, before they are accepted for execution.
All instructions that modify data must be preceded by a Write Enable (WREN) instruction to set the
Write Enable Latch (WEL) bit . This bit is returned to its reset state by the following events:
– Power-up
– Write Disable (WRDI) instruction completion or Write Status Register (WRSR) instruction
completion or Page Program (PP) instruction completion or Sector Erase (SE) instruction
completion or Block Erase (BE) instruction completion or Chip Erase (CE) instruction
completion
The Block Protect (BP2, BP1, BP0) bits allow part of the memory to be configured as read-only.
This is the Software Protected Mode (SPM).
The Write Protect (WP#) signal allows the Block Protect (BP2, BP1, BP0) bits and Status Register
Protect (SRP) bit to be protected. This is the Hardware Protected Mode (HPM).
In addition to the low power consumption feature, the Deep Power-down mode offers extra
software protection from inadvertent Write, Program and Erase instructions, as all instructions are
ignored except one particular instruction (the Release from Deep Power-down instruction).
Table 3. Protected Area Sizes Sector Organization
Status Register
Content
BP2
BP1
BP0
Bit
Bit
Bit
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Memory Content
Protect Areas
None
Block 3
Block 2 to 3
All
None
sector 0 to sector 59
sector 0 to sector 61
All
Protect Addresses
None
030000h-03FFFFh
020000h-03FFFFh
000000h-03FFFFh
None
000000h-03BFFFh
000000h-03DFFFh
000000h-03FFFFh
Protect
Density(KB)
None
64KB
128KB
256KB
None
240KB
248KB
256KB
Protect
Portion
None
Upper 1/4
Upper 1/2
All
None
Lower 30/32
Lower 31/32
All
This Data Sheet may be revised by subsequent versions
or modifications due to changes in technical specifications.
7
©2004 Eon Silicon Solution, Inc.,
www.eonssi.com
Rev. D, Issue Date: 2010/05/31
EON [ EON SILICON SOLUTION INC. ]
