ES25P80 Datasheet, PDF (22/35 Pages) Excel Semiconductor Inc. – 8Mbit CMOS 3.0 Volt Flash Memory with 75Mhz SPI Bus Interface

ADVANCED INFORMATION
EE SS II
Excel Semiconductor inc.
Release from Deep Power Down (RES)
The Release from Deep Power Down (RES) instruc-
tion provides the only way to exit the Deep Power
Down mode. Once the device has entered the Deep
Power Down mode, all instructions are ignored
except the Release from Deep Power Down (RES)
instruction. Executing this instruction takes the
device out of Deep Power Down mode.
The Release from Deep Power Down (RES) instruc-
tion is entered by driving Chip Select (CS#) Low, fol-
lowed by the instruction code on Serial Data Input
(SI). Chip Select (CS#) must be driven Low for the
entire duration of the sequence.
The instruction sequence is shown in Figure 17.
Driving Chip Select (CS#) High after the 8-bit instruc-
tion byte has been received by the device, but before
the whole of the 8-bit Electronic Signature has been
transmitted for the first time, still insures that the
device is put into Standby mode. If the device was
previously in the Deep Power Down mode, though,
the transition to the Stand-by Power mode is delayed
by t_RES, and Chip Select (CS#) must remain High for
at least t_RES(max) , as specified in Table 8. Once in
the Stand-by Power mode, the device waits to be
selected, so that it can receive, decode and execute
instructions.
Release from Deep Power Down and
Read Electronic Signature (RES)
Once the device has entered Deep Power Down
mode, all instructions are ignored except the RES
instruction. The RES instruction can also be used to
read the old style 8-bit Electronic Signature of the
device on the SO pin. The RES instruction always
provides access to the Electronic Signature of the
device (except while an Erase, Program or WRSR
cycle is in progress), and can be applied even if DP
mode has not been entered. Any RES instruction
executed while an Erase, Program or WRSR cycle
is in progress is not decoded, and has no effect on
the cycle in progress.
The device features an 8-bit Electronic Signature,
whose value for the ES25P80 is 13h. This can be
read using RES instruction.
The device is first selected by driving Chip Select
(CS#) Low. The instruction code is followed by 3
dummy bytes, each bit being latched-in on Serial
Data Input (SI) during the rising edge of Serial Clock
(SCK). Then, the 8-bit Electronic Signature, stored
in the memory, is shifted out on Serial Data Output
(SO), each bit being shifted out during the falling
edge of Serial Clock (SCK).
The instruction sequence is shown in Figure 18.
CS#
SCK
SI
0
1
2
3
4
5
6
7
t_RES
Instruction
1
0
1
0
1
0
1
1
Deep Power Down Mode Standby Mode
Figure 17. Release from Deep Power Down Instruction Sequence
ES25P80
22
Rev. 0D May, 11, 2006