
W25Q64FV
6.2.14
Fast Read Quad Output (6Bh)
The Fast Read Quad Output (6Bh) instruction is similar to the Fast Read Dual Output (3Bh) instruction
except that data is output on four pins, IO 0 , IO 1 , IO 2 , and IO 3 . A Quad enable of Status Register-2 must be
executed before the device will accept the Fast Read Quad Output Instruction (Status Register bit QE
must equal 1). The Fast Read Quad Output Instruction allows data to be transferred from the W25Q64FV
at four times the rate of standard SPI devices.
The Fast Read Quad Output instruction can operate at the highest possible frequency of F R (see AC
Electrical Characteristics). This is accomplished by adding eight “dummy” clocks after the 24 -bit address
as shown in Figure 13. The dummy clocks allow the device's internal circuits additional time for setting up
the initial address. The input data during the dummy clocks is “don’t care”. However, the IO pins should
be high-impedance prior to the falling edge of the first data out clock.
/CS
Mode 3
0
1
2
3
4
5
6
7
8
9
10
28
29
30
31
CLK
Mode 0
Instruction (6Bh)
24-Bit Address
IO 0
23
22
21
3
2
1
0
IO 1
IO 2
IO 3
/CS
* = MSB
High Impedance
High Impedance
High Impedance
*
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
CLK
Dummy Clocks
IO 0 switches from
Input to Output
IO 0
IO 1
IO 2
IO 3
0
High Impedance
High Impedance
High Impedance
4
5
6
7
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
Byte 1
Byte 2
Byte 3
Byte 4
Figure 13. Fast Read Quad Output Instruction (SPI Mode only)
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Publication Release Date:
October 07, 2013
Revision L