mx25l1635dzni-10g Macronix International Co., mx25l1635dzni-10g Datasheet - Page 25

• Manufacturer Part Number: mx25l1635dzni-10g
• Description: Serial Flash Memory
• Manufacturer: Macronix International Co.

Table 8. Security Register Definition
P/N: PM1374
(21) 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 Regis-
ter 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 custom-
er 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, main array access is not allowed.
Continuously Program Mode( CP mode) bit. The Continuously Program Mode bit indicates the status of CP
mode, "0" indicates not in CP mode; "1" indicates in CP mode.
(22) 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 Se-
cured 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.
volatile bit
reserved
bit7
x
volatile bit
reserved
bit6
x
volatile bit
reserved
bit5
x
Program mode
Program mode
Continuously
1=CP mode
(CP mode)
(default=0)
volatile bit
0=normal
bit4
volatile bit
25
reserved
bit3
x
volatile bit
reserved
bit2
x
MX25L1635D
program/erase
non-volatile bit non-volatile bit
1 = lock-down
0 = not lock-
(indicate if
lock-down
(cannot
LDSO
down
OTP)
bit1
REV. 1.7, MAR. 30, 2009
0 = non-factory
Secrured OTP
indicator bit
1 = factory
bit0
lock
lock