EN25LF20_1 Datasheet, PDF (6/32 Pages) Eon Silicon Solution Inc. – 2 Megabit Serial Flash Memory with 4Kbytes Uniform Sector

Figure 3. SPI Modes
EN25LF20
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, 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 internal Erase cycle
(of duration tSE tBE or tCE). 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, BE or
CE ) can be achieved by not waiting for the worst case delay (tW, tPP, tSE, tBE or tCE). 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 into the Stand-by
Power mode. The device consumption drops to ICC1.
The Deep Power-down mode is entered when the specific instruction (the Enter Deep Power-down
Mode (DP) instruction) is executed. The device consumption drops further to ICC2. The device remains
in this 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.
WIP bit. The Write In Progress (WIP) 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.
This Data Sheet may be revised by subsequent versions
6
or modifications due to changes in technical specifications.
©2004 Eon Silicon Solution, Inc.,
Rev. D, Issue Date: 2010/05/31
www.eonssi.com