Da ta
Shee t
(Prelimi nar y)
Figure 9.1
Read Data Bytes (READ) Command Sequence
CS#
Mode
3
0
1
2
3
4
5
6
7
8
9 10
28 29
30 31 32 33 34 35 36 37 38 39
SCK
Mode 0
Command
24-Bit Address
SI
23 22 21
MSB
3
2 1 0
Data Out 1
Data Out 2
SO
Hi-Z
7 6 5 4
3
2
MSB
1 0 7
9.2
Read Data Bytes at Higher Speed (FAST_READ)
The FAST_READ command reads data from the memory array at the frequency (f
SCK
) presented at the SCK
input, with a maximum speed of 50 MHz. The host system must first select the device by driving CS# low. The
FAST_READ command is then written to SI, followed by a 3-byte address (A23-A0) and a dummy byte. Each
bit is latched on the rising edge of SCK. The memory array data, at that address, are output serially on SO at
a frequency f
SCK
, on the falling edge of SCK.
The FAST_READ command sequence is shown in
and
The first byte specified can be at
any location. The device automatically increments to the next higher address after each byte of data is output.
The entire memory array can therefore be read with a single FAST_READ command. When the highest
address is reached, the address counter reverts to 00000h, allowing the read sequence to continue
indefinitely.
The FAST_READ command is terminated by driving CS# high at any time during data output. The device
rejects any FAST_READ command issued while it is executing a program, erase, or Write Status Register
operation, and continues the operation uninterrupted.
Figure 9.2
Read Data Bytes at Higher Speed (FAST_READ) Command Sequence
CS#
Mode
3
0
1
2
5
6
7
8
9
28 29
30
31 32 33
34 35 36 37 38
39
40 41
42 43 44 45
46
3
4
10
47
SCK
Mode 0
Command
SI
SO
Hi-Z
24-Bit Address
23 22 21
3
2
1
0
7
Dummy Byte
6
5
4
3
2
1
0
7
MSB
6
5
4
3
2
1
0
7
MSB
DATA OUT 2
DATA OUT 1
9.3
Read Identification (RDID)
The Read Identification (RDID) command outputs the one-byte manufacturer identification, followed by the
two-byte device identification, to the host system.
JEDEC assigns the manufacturer identification byte; for Spansion devices it is 01h. The device manufacturer
assigns the device identification: the first byte provides the memory type; the second byte indicates the
memory capacity. See
or
for device ID data.
The host system must first select the device by driving CS# low. The RDID command is then written to SI,
and each bit is latched on the rising edge of SCK. The 24-bit device identification data is output from the
memory array on SO at a frequency f
SCK
, on the falling edge of SCK.
August 31, 2006 S25FL040A_00_B0
S25FL040A
15
SPANSION [ SPANSION ]
