EN25S40A Datasheet, PDF (15/68 Pages) Eon Silicon Solution Inc. – 4 Megabit 1.8V Serial Flash Memory with 4Kbyte Uniform Sector

EN25S40A
3. If user is not sure it is in SPI or Quad mode, we suggest to execute sequence as follows:
Quad Reset-Enable (RSTEN) (66h) -> Quad Reset (RST) (99h) -> SPI Reset-Enable (RSTEN) (66h)
-> SPI Reset (RST) (99h) to reset.
4. The reset command could be executed during embedded program and erase process, QPI mode,
Continue EB mode and suspend mode to back to SPI mode.
5. This flow cannot release the device from Deep power down mode.
6. The Status Register Bit and Suspend Status Register Bit will reset to default value after reset done.
7. If user reset device during erase, the embedded reset cycle software reset latency will take about
28us in worst case.
Enable Quad Peripheral Interface mode (EQPI) (38h)
The Enable Quad Peripheral Interface mode (EQPI) instruction will enable the flash device for Quad
SPI bus operation. Upon completion of the instruction, all instructions thereafter will be 4-bit multiplexed
input/output until a power cycle or “ Reset Quad I/O instruction “ instruction, as shown in Figure 7. The
device did not support the Read Data Bytes (READ) (03h), Dual Output Fast Read (3Bh), Dual
Input/Output FAST_READ (BBh) and Quad Input Page Program (32h) modes while the Enable Quad
Peripheral Interface mode (EQPI) (38h) turns on.
Figure 7. Enable Quad Peripheral Interface mode Sequence Diagram
Reset Quad I/O (RSTQIO) or Release Quad I/O Fast Read Enhancement Mode (FFh)
The Reset Quad I/O instruction resets the device to 1-bit Standard SPI operation. To execute a Reset
Quad I/O operation, the host drives CS# low, sends the Reset Quad I/O command cycle (FFh) then,
drives CS# high. This command can’t be used in Standard SPI mode.
User also can use the FFh command to release the Quad I/O Fast Read Enhancement Mode. The
detail description, please see the Quad I/O Fast Read Enhancement Mode section.
Note:
If the system is in the Quad I/O Fast Read Enhance Mode under QPI Mode, it is necessary to execute
FFh command by two times. The first FFh command is to release Quad I/O Fast Read Enhance Mode,
and the second FFh command is to release QPI Mode.
This Data Sheet may be revised by subsequent versions
15
or modifications due to changes in technical specifications.
©2013 Eon Silicon Solution, Inc.,
Rev. A, Issue Date: 2013/12/30
www.eonssi.com