W25Q256FVBIF-TR Datasheet, PDF (91/108 Pages) Winbond – 3V 256M-BIT SERIAL FLASH MEMORY WITH DUAL/QUAD SPI & QPI

W25Q256FV
8.2.50 Read Block/Sector Lock (3Dh)
The Individual Block/Sector Lock provides an alternative way to protect the memory array from adverse
Erase/Program. In order to use the Individual Block/Sector Locks, the WPS bit in Status Register-3 must
be set to 1. If WPS=0, the write protection will be determined by the combination of CMP, TB, BP[3:0] bits
in the Status Registers. The Individual Block/Sector Lock bits are volatile bits. The default values after
device power up or after a Reset are 1, so the entire memory array is being protected.
To read out the lock bit value of a specific block or sector as illustrated in Figure 4d, a Read
Block/Sector Lock command must be issued by driving /CS low, shifting the instruction code “3Dh” into
the Data Input (DI) pin on the rising edge of CLK, followed by a 24/32-bit address. The Block/Sector Lock
bit value will be shifted out on the DO pin at the falling edge of CLK with most significant bit (MSB) first as
shown in Figure 54. If the least significant bit (LSB) is 1, the corresponding block/sector is locked; if
LSB=0, the corresponding block/sector is unlocked, Erase/Program operation can be performed.
/CS
CLK
DI
(IO0)
DO
(IO1)
Mode 3
0
Mode 0
* ^{= MSB}
1 2 3 4 5 6 7 8 9 10
28 29 30 31 32 33 34 35 36 37 38 39
Instruction (3Dh)
24-Bit Address
23 22 21
*
High Impedance
3210
Lock Value Out
XXXXXXX0
*
Mode 3
Mode 0
Figure 54a. Read Block Lock Instruction (SPI Mode)
32-Bit Address is required when the device is operating in 4-Byte Address Mode
/CS
CLK
IO₀
Mode 3
Mode 0
0 1 2 3 4 5 6 7 8 9 Mode 3
Instruction
3Dh
A23-16
A15-8
A7-0
Mode 0
IOs switch from
Input to Output
20 16 12 8 4 0 X 0
IO₁
21 17 13 9 5 1 X X
IO₂
22 18 14 10 6 2 X X
IO₃
23 19 15 11 7 3 X X
Lock
Value
Figure 54b. Read Block Lock Instruction (QPI Mode)
32-Bit Address is required when the device is operating in 4-Byte Address Mode
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Publication Release Date: February 11, 2015
Preliminary – Revision H