W25Q256JVEIQ-TR Datasheet, PDF (76/92 Pages) Winbond – 3V 256M-BIT SERIAL FLASH MEMORY WITH DUAL/QUAD SPI

W25Q256JV
8.2.48 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
57. 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 57. Read Block Lock Instruction
32-Bit Address is required when the device is operating in 4-Byte Address Mode
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