Individual Block/Sector Unlock (39H) - Winbond SpiFlash W25Q256FV Manual

8.2.49

Individual Block/Sector Unlock (39h)

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 unlock a specific block or sector as illustrated in Figure 4d, an Individual Block/Sector Unlock
command must be issued by driving /CS low, shifting the instruction code "39h" into the Data Input (DI) pin
on the rising edge of CLK, followed by a 24/32-bit address and then driving /CS high.
32-Bit Address is required when the device is operating in 4-Byte Address Mode
32-Bit Address is required when the device is operating in 4-Byte Address Mode
FOR MOBILE APPLICATIONS
Figure 53a. Individual Block Unlock Instruction (SPI Mode)
Figure 53b. Individual Block Unlock Instruction (QPI Mode)
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W25Q256FV