S25FL040A Meet Spansion Inc., S25FL040A Datasheet - Page 17

• Manufacturer Part Number: S25FL040A
• Description: Small Sector For Boot And Parameter Storage 4-megabit Cmos 3.0 Volt Flash Memory With 50 Mhz Spi Bus Interface
• Manufacturer: Meet Spansion Inc.

9.2
July 2, 2007 S25FL040A_00_B2
Read Data Bytes at Higher Speed (FAST_READ)
The FAST_READ command reads data from the memory array at the frequency (f
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
The FAST_READ command sequence is shown in
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.
SCK
SO
CS#
SI
CS#
SCK
SI
SO
Mode 3
Mode 0
Hi-Z
Mode 3
Mode 0
Hi-Z
Figure 9.2 Read Data Bytes at Higher Speed (FAST_READ) Command Sequence
SCK
0
, on the falling edge of SCK.
0
1
2
Command
1
3
Command
2
Figure 9.1 Read Data Bytes (READ) Command Sequence
D a t a
4
3
5
4
6
7
5
23 22 21
S h e e t
8
6
9
24-Bit Address
S25FL040A
7
MSB
10
23 22 21
8
28 29 30
3
9
24-Bit Address
2
10
1
Figure 9.2
31 32 33
0
3 2 1 0
28
7
6
29
Dummy Byte
34 35 36 37 38
5
30
and
4
31 32 33 34 35 36 37 38 39
3
MSB
Table
7 6 5
2
1
9.5. The first byte specified can be
39
0
MSB
Data Out 1
7
40 41
4
6
5
3 2 1 0 7
42 43 44 45
DATA OUT 1
SCK
4
) presented at the SCK
3
2
1
46
0
47
Data Out 2
MSB
7
DATA OUT 2
17