SA25F005 Saifun, SA25F005 Datasheet - Page 24

• Manufacturer Part Number: SA25F005
• Description: 512Kb Serial Flash
• Manufacturer: Saifun

Fast Read (FAST_READ)
The Fast Read instruction is included in the
device in order for it to be compatible with
other SPI Flash devices. Both the READ
and FAST_READ instructions read the
memory at the specified SCK frequency
(F
Reading the memory via the serial SPI link
requires the following sequence:
1. After the CSb line is pulled low to
2. Upon completion, any data on the
SCK
SCK
CS
SO
select
opcode is transmitted via the SI
line, followed by the 3-byte address
and a dummy byte (address bits
A23 to A18 are Don’t Care).
SI line is ignored.
SI
), with a maximum speed of 25 MHz.
the
0
1
High Impedance
2
device,
Instruction
Figure 15. Fast Read (FAST_READ) Instruction Sequence
3
4
5
6
the
7
23
8
22
9
READ
21
10
Address
24-Bit
28
3
29
2
30
1
31
0
32
7
33
6
3. The data (D7-D0) at the specified
If only one byte is to be read, the CSb line
should be driven high after the data comes
out.
continued,
automatically
continues to shift out. When the highest
address is reached, the address counter
rolls over to the lowest address, enabling
the entire memory to be read in one
continuous READ cycle. The instruction
sequence is shown in Figure 15.
Driving
FAST_READ instruction, which can be
done at any time during data output. Any
FAST_READ instruction executed while an
Erase or Program cycle is in progress is
rejected without having any effect on the
cycle in progress.
34
Dummy Byte
5
35
4
address is then shifted out onto the
SO line. Each bit is shifted out at a
maximum frequency of F
36
3
The
37
2
38
1
CSb
0
39
MSB
7
READ
as
40
6
41
incremented
5
42
DATA OUT 1
SA25F005 Advanced Information
the
high
4
43
3
44
sequence
2
byte
45
1
terminates
46
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0
47
SCK
MSB
7
address
DATA OUT 2
.
and
can
SAIFUN
data
the
be
is
24