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

EN25F16

Rev. C, Issue Date: 2008/06/23

OPERATING FEATURES

SPI Modes

The EN25F16 is accessed through an SPI compatible bus consisting of four signals: Serial Clock

(CLK), Chip Select (CS#), Serial Data Input (DI) and Serial Data Output (DO). Both SPI bus

operation Modes 0 (0,0) and 3 (1,1) are supported. The primary difference between Mode 0 and

Mode 3, as shown in Figure 3, concerns the normal state of the CLK signal when the SPI bus

master is in standby and data is not being transferred to the Serial Flash. For Mode 0 the CLK signal

is normally low. For Mode 3 the CLK signal is normally high. In either case data input on the DI pin is

sampled on the rising edge of the CLK. Data output on the DO pin is clocked out on the falling edge

of CLK.

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

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

grammed at a time (changing bits from 1 to 0), provided that they lie in consecutive addresses on

the same page of memory.

Sector Erase, Block Erase and Chip 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 a sector at a

time, using the Sector Erase (SE) instruction, a block at a time using the Block Erase (BE)

instruction or throughout the entire memory, using the Chip Erase (CE) instruction. This starts an

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, BE

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 into

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

mains in this mode until another specific instruction (the Release from Deep Power-down Mode and

Read Device ID (RDI) instruction) is executed.