ACE25AB400G

Serial NOR Flash Memory 4M bits 3.0V Dual I/O Serial Flash Memory with 4KB Uniform Sector

VER 1.1

9

Write Enable (WREN) (06H)

The Write Enable (WREN) command is for setting the Write Enable Latch (WEL) bit. The Write Enable

Latch (WEL) bit must be set prior to every Page Program (PP), Sector Erase (SE), Block Erase (BE), Chip

Erase (CE) and Write Status Register (WRSR) command. The Write Enable (WREN) command

sequence: CS# goes low→Sending the Write Enable command→CS# goes high.

Write Enable for Volatile Status Register (50H)

The non-volatile Status Register bits can also be written to as volatile bits. This gives more flexibility to

change the system configuration and memory protection schemes quickly without waiting for the typical

non- volatile bit write cycles or affecting the endurance of the Status Register non-volatile bits. The Write

Enable for Volatile Status Register command must be issued prior to a Write Status Register command

and any other commands can't be inserted between them. Otherwise, Write Enable for Volatile Status

Register will be cleared. The Write Enable for Volatile Status Register command will not set the Write

Enable Latch bit, it is only valid for the Write Status Register command to change the volatile Status

Register bit values.

Figure1. Write Enable Sequence Diagram

Figure2. Write Enable for Volatile Status Register Sequence Diagram