mx25l12845e Macronix International Co., mx25l12845e Datasheet - Page 30

• Manufacturer Part Number: mx25l12845e
• Description: Mx25l12845e High Performance Serial Flash Specification Preliminary
• Manufacturer: Macronix International Co.

WPSEL Flow
P/N: PM1428
(28) Write Protection Selection (WPSEL)
When the system accepts and executes WPSEL instruction, the bit 7 in security register will be set. It will activate
SBLK, SBULK, RDBLOCK, GBLK, GBULK etc instructions to conduct block lock protection and replace the original
Software Protect Mode (SPM) use (BP3~BP0) indicated block methods.
The sequence of issuing WPSEL instruction is: CS# goes low → sending WPSEL instruction to enter the individual
block protect mode → CS# goes high.
Every time after the system is powered-on, and the Security Register bit 7 is checked to be WPSEL=1, all the
blocks or sectors will be write protected by default. User may only unlock the blocks or sectors via SBULK and
GBULK instruction. Program or erase functions can only be operated after the Unlock instruction is conducted.
Under the individual block protection mode (WPSEL=1), hardware protection is performed by driving WP#=0. Once
WP#=0 all array blocks/sectors are protected regardless of the contents of SRAM lock bits.
WPSEL instruction function flow is as follows:
Block protected by individual lock
block protected by BP[3:0]
RDSCUR(2Bh) command
WPSEL(68h) command
WPSEL set successfully
(SBLK, SBULK, … etc).
RDSCUR(2Bh) command
RDSR command
WPSEL disable,
WPSEL enable.
WPSEL=1?
WPSEL=1?
WIP=0?
start
No
Yes
Yes
No
No
30
Yes
WPSEL set fail
MX25L12845E
REV. 0.06, MAR. 05, 2009