GD25B256DFIS datasheet(49/82 Pages) GIGADEVICE

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3.3V Uniform Sector

Dual and Quad Serial Flash

GD25B256D

7.23.

Enter 4-Byte Address Mode (B7H)

The Enter 4-Byte Address Mode command enables accessing the address length of 32-bit for the memory area of

higher density (larger than 128Mb). The device default is in 24-bit address mode; after sending out the EN4B instruction,

the bit8

(ADS bit) of status register will be automatically set to “1” to indicate the 4-Byte address mode has been enabled.

Once the 4-Byte address mode is enabled, the address length becomes 32-bit instead of the default 24-bit.

All instructions are accepted normally, and just the address bit is changed from 24-bit to 32-bit.

The sequence of issuing EN4B instruction is: CS# goes low  sending Enter 4-Byte mode command CS# goes

high.

Figure 54 Enter 4-Byte Address Mode Sequence Diagram

7.24.

Exit 4-Byte Address Mode (E9H)

The Exit 4-Byte Address Mode command is executed to exit the 4-Byte address mode and return to the default 3-Byte

address mode. After sending out the EX4B instruction, the bit8

(ADS bit) of status register will be cleared to “0” to indicate

the exit of the 4-Byte address mode. Once exiting the 4-Byte address mode, the address length will return to 24-bit.

The sequence of issuing EN4B instruction is: CS# goes low  sending Exit 4-Byte Address Mode command CS#

goes high.

Figure 55 Exit 4-Byte Address Mode Sequence Diagram

Command

B7H

CS#

SCLK

High-Z

Command

E9H

CS#

SCLK

High-Z

GD25B256DFIS Arkusz danych(PDF) 49 Page - GigaDevice Semiconductor (Beijing) Inc.