EN25B40 Datasheet, PDF (18/36 Pages) Eon Silicon Solution Inc. – 4 Mbit Serial Flash Memory with Boot and Parameter Sectors

EN25B40
Deep Power-down (DP) (B9h)
Executing the Deep Power-down (DP) instruction is the only way to put the device in the lowest con-
sumption mode (the Deep Power-down mode). It can also be used as an extra software protection
mechanism, while the device is not in active use, since in this mode, the device ignores all Write, Program
and Erase instructions.
Driving Chip Select (CS#) High deselects the device, and puts the device in the Standby mode (if there is
no internal cycle currently in progress). But this mode is not the Deep Power-down mode. The Deep
Power-down mode can only be entered by executing the Deep Power-down (DP) instruction, to reduce the
standby current (from ICC1 to ICC2, as specified in Table 8.).
Once the device has entered the Deep Power-down mode, all instructions are ignored except the Release
from Deep Power-down and Read Device ID (RDI) instruction. This releases the device from this mode.
The Release from Deep Power-down and Read Device ID (RDI) instruction also allows the Device ID of
the device to be output on Serial Data Output (DO).
The Deep Power-down mode automatically stops at Power-down, and the device always Powers-up in the
Standby mode. The Deep Power-down (DP) instruction is entered by driving Chip Select (CS#) Low,
followed by the instruction code on Serial Data Input (DI). Chip Select (CS#) must be driven Low for the
entire duration of the sequence.
The instruction sequence is shown in Figure 14..Chip Select (CS#) must be driven High after the eighth bit
of the instruction code has been latched in, otherwise the Deep Power-down (DP) instruction is not
executed. As soon as Chip Select (CS#) is driven High, it requires a delay of t_DP before the supply current
is reduced to ICC2 and the Deep Power-down mode is entered.
Any Deep Power-down (DP) instruction, while an Erase, Program or Write cycle is in progress, is rejected
without having any effects on the cycle that is in progress.
Release from Deep Power-down and Read Device ID (RDI)
Once the device has entered the Deep Power-down mode, all instructions are ignored except the Release
from Deep Power-down and Read Device ID (RDI) instruction. Executing this instruction takes the device
out of the Deep Power-down mode.
Please note that this is not the same as, or even a subset of, the JEDEC 16-bit Electronic Signature that
is read by the Read Identifier (RDID) instruction. The old-style Electronic Signature is supported for
reasons of backward compatibility, only, and should not be used for new designs. New designs should,
instead, make use of the JEDEC 16-bit Electronic Signature, and the Read Identifier (RDID) instruction.
This Data Sheet may be revised by subsequent versions ₁₈ ©2004 Eon Silicon Solution, Inc., www.essi.com.tw
or modifications due to changes in technical specifications.
Rev. E, Issue Date: 2007/5/3