This Data Sheet may be revised by subsequent versions

©2004 Eon Silicon Solution, Inc., www.essi.com.tw

or modifications due to changes in technical specifications.

9

EN25P40

Rev. D, Issue Date: 2006/12/25

Write Enable (WREN) (06h)

The Write Enable (WREN) instruction (Figure 5) sets the Write Enable Latch (WEL) bit. The Write Enable

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

Write Status Register (WRSR) instruction.

The Write Enable (WREN) instruction is entered by driving Chip Select (CS#) Low, sending the instruction

code, and then driving Chip Select (CS#) High.

Write Disable (WRDI) (04h)

The Write Disable instruction (Figure 6) resets the Write Enable Latch (WEL) bit in the Status Register to

a 0. The Write Disable instruction is entered by driving Chip Select (CS#) low, shifting the instruction code

“04h” into the DI pin and then driving Chip Select (CS#) high. Note that the WEL bit is automatically reset

after Power-up and upon completion of the Write Status Register, Page Program, Sector Erase, and Bulk

Erase instructions.

Read Status Register (RDSR) (05h)

The Read Status Register (RDSR) instruction allows the Status Register to be read. The Status Register

may be read at any time, even while a Program, Erase or Write Status Register cycle is in progress.

When one of these cycles is in progress, it is recommended to check the Write In Progress (WIP) bit

before sending a new instruction to the device. It is also possible to read the Status Register continuously,

as shown in Figure 7.