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.

7

EN25P32

Rev. C, Issue Date: 2007/10/18

Figure 3. SPI Modes

Page Programming

To program one data byte, two instructions are required: Write Enable (WREN), which is one byte, and a

Page Program (PP) sequence, which consists of four bytes plus data. This is followed by the internal

Program cycle (of duration tPP).

To spread this overhead, the Page Program (PP) instruction allows up to 256 bytes to be programmed at

a time (changing bits from 1 to 0), provided that they lie in consecutive addresses on the same page of

memory.

Sector Erase and Bulk Erase

The Page Program (PP) instruction allows bits to be reset from 1 to 0. Before this can be applied, the

bytes of memory need to have been erased to all 1s (FFh). This can be achieved either a sector at a time,

using the Sector Erase (SE) instruction, or throughout the entire memory, using the Bulk Erase (BE)

instruction. This starts an internal Erase cycle (of duration tSE or tBE). The Erase instruction must be

preceded by a Write Enable (WREN) instruction.

Polling During a Write, Program or Erase Cycle

A further improvement in the time to Write Status Register (WRSR), Program (PP) or Erase (SE or BE)

can be achieved by not waiting for the worst case delay (tW, tPP, tSE, or tBE). The Write In Progress

(WIP) bit is provided in the Status Register so that the application program can monitor its value, polling it

to establish when the previous Write cycle, Program cycle or Erase cycle is complete.

Active Power, Stand-by Power and Deep Power-Down Modes

When Chip Select (CS#) is Low, the device is enabled, and in the Active Power mode. When Chip Select

(CS#) is High, the device is disabled, but could remain in the Active Power mode until all internal cycles

have completed (Program, Erase, Write Status Register). The device then goes in to the Stand-by Power

The Deep Power-down mode is entered when the specific instruction (the Enter Deep Power-down Mode

mode until another specific instruction (the Release from Deep Power-down Mode and Read Device ID

(RDI) instruction) is executed.

All other instructions are ignored while the device is in the Deep Power-down mode. This can be used as

an extra software protection mechanism, when the device is not in active use, to protect the device from

inadvertent Write, Program or Erase instructions.

Status Register.The Status Register contains a number of status and control bits that can be read or set

(as appropriate) by specific instructions.

BUSY bit. The BUSY bit indicates whether the memory is busy with a Write Status Register, Program or

Erase cycle.

WEL bit. The Write Enable Latch (WEL) bit indicates the status of the internal Write Enable Latch.

BP2, BP1, BP0 bits. The Block Protect (BP2, BP1, BP0) bits are non-volatile. They define the size of the

area to be software protected against Program and Erase instructions.