EN25S40A Datasheet, PDF (8/68 Pages) Eon Silicon Solution Inc. – 4 Megabit 1.8V Serial Flash Memory with 4Kbyte Uniform Sector

EN25S40A
Page Programming
To program one data byte, two instructions are required: Write Enable (WREN), which is one byte, and
a Page Program (PP) or Quad Input Page Program (QPP) sequence, which consists of four bytes plus
data. This is followed by the internal Program cycle (of duration t_PP).
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, Half Block 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, half a block at a time using the Half Block Erase (HBE)
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 t_SE, t_HBE, t_BE or t_CE).
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, HBE ,
BE or CE) can be achieved by not waiting for the worst case delay (t_W, t_PP, t_SE, t_HBE, t_BE or t_CE). 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 I_CC1.
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 I_CC2. 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 and Suspend Status Register
The Status Register and Suspend Status Register contain 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.
BP3, BP2, BP1, BP0 bits. The Block Protect (BP3, BP2, BP1, BP0) bits are non-volatile. They define
the size of the area to be software protected against Program and Erase instructions.
WHDIS bit. The WP# and Hold# Disable bit (WHDIS bit), non-volatile bit, it indicates the WP# and
HOLD# are enabled or not. When it is “0” (factory default), the WP# and HOLD# are enabled. On the
other hand, while WHDIS bit is “1”, the WP# and HOLD# are disabled. No matter WHDIS is “0＂ or
“1＂, the system can executes Quad Input/Output FAST_READ (EBh), Quad Input Page Program (32h)
or EQPI (38h) command directly. User can use Flash Programmer to set WHDIS bit as “1＂ and then
the host system can let WP# and HOLD# keep floating in SPI mode.
SRP bit / OTP_LOCK bit The Status Register Protect (SRP) bit operates in conjunction with the Write
Protect (WP#) signal. The Status Register Protect (SRP) bit and Write Protect (WP#) signal allow the
device to be put in the Hardware Protected mode. In this mode, the non-volatile bits of the Status
Register (SRP, BP3, BP2, BP1, BP0) become read-only bits.
In OTP mode, this bit serves as OTP_LOCK bit, user can read/program/erase OTP sector as normal
sector while OTP_LOCK bit value is equal 0, after OTP_LOCK bit is programmed with 1 by WRSR
command, the OTP sector is protected from program and erase operation. The OTP_LOCK bit can only
be programmed once.
This Data Sheet may be revised by subsequent versions
8
or modifications due to changes in technical specifications.
©2013 Eon Silicon Solution, Inc.,
Rev. A, Issue Date: 2013/12/30
www.eonssi.com