ACE25AB400G

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

VER 1.1

16

Sector Erase (SE) (20H)

The Page Program (PP) command is for programming the memory. A Write Enable (WREN) command

must previously have been executed to set the Write Enable Latch (WEL) bit before sending the Page

Program com- mand.

The Page Program (PP) command is entered by driving CS# Low, followed by the command code, three

address bytes and at least one data byte on SI. If the 8 least significant address bits (A7-A0) are not all

zero, all transmitted data that goes beyond the end of the current page are programmed from the start

address of the same page (from the address whose 8 least significant bits (A7-A0) are all zero). CS# must

be driven low for the entire duration of the sequence. The Page Program command sequence: CS# goes

low

 s e n d ing P a g e P ro

- gram command

 3

-byte address on SI

 at lea

goes high. The command sequence is shown in Figure 10. If more than 256 bytes are sent to the device,

previously latched data are discarded and the last 256 data bytes are guaranteed to be programmed

correctly within the same page. If less than 256 data bytes are sent to device, they are correctly

programmed at the requested addresses without having any effects on the other bytes of the same page.

CS# must be driven high after the eighth bit of the last data byte has been latched in; otherwise the Page

Program (PP) command is not executed.

As soon as CS# is driven high, the self-timed Page Program cycle (whose duration is tPP) is initiated.

While the Page Program cycle is in progress, the Status Register may be read to check the value of the

Write In Pro- gress (WIP) bit. The Write In Progress (WIP) bit is 1 during the self-timed Page Program

cycle, and is 0 when it is completed. At some unspecified time before the cycle is completed, the Write

Enable Latch (WEL) bit is reset.

A Page Program (PP) command applied to a page which is protected by the Block Protect (BP1, BP0) is

not executed.

Figure11. Sector Erase Sequence Diagram