mx25l12805d Macronix International Co., mx25l12805d Datasheet - Page 19

• Manufacturer Part Number: mx25l12805d
• Description: 128m-bit [x 1] Cmos Serial Flash
• Manufacturer: Macronix International Co.

Table of Security Register Definition
(18) Write Security Register (WRSCUR)
The WRSCUR instruction is for changing the values of Security Register Bits. Unlike write status register, the WREN
instruction is not required before sending WRSCUR instruction. The WRSCUR instruction may change the values of bit1
(LDSO bit) for customer to lock-down the 512-bit Secured OTP area. Once the LDSO bit is set to "1", the Secured OTP
area cannot be updated any more.
The sequence of issuing WRSCUR instruction is :CS# goes low-> sending WRSCUR instruction -> CS# goes high.
The CS# must go high exactly at the boundary; otherwise, the instruction will be rejected and not executed.
P/N: PM1310
(17) Read Security Register (RDSCUR)
The RDSCUR instruction is for reading the value of Security Register bits. The Read Security Register can be read at any
time (even in program/erase/write status register/write security register condition) and continuously.
The sequence of issuing RDSCUR instruction is : CS# goes low-> send ing RDSCUR instruction -> Security Register data
out on SO-> CS# goes high.
The definition of the Security Register bits is as below:
Secured OTP Indicator bit. The Secured OTP indicator bit shows the chip is locked by factory before ex- factory or not.
When it is "0", it indicates non- factory lock; "1" indicates factory- lock.
Lock-down Secured OTP (LDSO) bit. By writing WRSCUR instruction, the LDSO bit may be set to "1" for customer lock-
down purpose. However, once the bit is set to "1" (lock-down), the LDSO bit and the 512-bit Secured OTP area cannot
be update any more. While it is in 512-bit secured OTP mode, array access is not allowed.
volatile bit
reserved
bit7
x
volatile bit
reserved
bit6
x
volatile bit
reserved
bit5
x
volatile bit
reserved
bit4
x
19
volatile bit
reserved
bit3
x
MX25L12805D
volatile bit
bit2
x
0
non-volatile bit non-volatile bit
program/erase
1 = lock-down
0 = not lock-
(indicate if
lock-down
(cannot
LDSO
OTP)
down
bit1
REV. 1.1, OCT. 01, 2008
Secrured OTP
indicator bit
factory lock
1 = factory
0 = non-
lock
bit0