w25q40bv Winbond Electronics Corp America, w25q40bv Datasheet - Page 36

• Manufacturer Part Number: w25q40bv
• Description: 4m-bit Serial Flash Memory With Dual And Quad Spi
• Manufacturer: Winbond Electronics Corp America

8.2.18
The Set Burst with Wrap (77h) instruction is used in conjunction with “Fast Read Quad I/O” and “Word
Read Quad I/O” instructions to access a fixed length of 8/16/32/64-byte section within a 256-byte page.
Certain applications can benefit from this feature and improve the overall system code execution
performance.
Similar to a Quad I/O instruction, the Set Burst with Wrap instruction is initiated by driving the /CS pin low
and then shifting the instruction code “77h” followed by 24 dummy bits and 8 “Wrap Bits”, W7-0. The
instruction sequence is shown in figure 17. Wrap bit W7 and the lower nibble W3-0 are not used.
Once W6-4 is set by a Set Burst with Wrap instruction, all the following “Fast Read Quad I/O” and “Word
Read Quad I/O” instructions will use the W6-4 setting to access the 8/16/32/64-byte section within any
page. To exit the “Wrap Around” function and return to normal read operation, another Set Burst with
Wrap instruction should be issued to set W4 = 1. The default value of W4 upon power on is 1. In the case
of a system Reset while W4 = 0, it is recommended that the controller issues a Set Burst with Wrap
instruction to reset W4 = 1 prior to any normal Read instructions since W25Q40BV does not have a
hardware Reset Pin.
CLK
CLK
/CS
/CS
IO
IO
IO
IO
IO
IO
IO
IO
Set Burst with Wrap (77h)
2
2
3
3
1
1
0
0
W6, W5
0 0
0 1
1 0
1 1
Mode 3
Mode 3
Mode 0
Mode 0
Wrap Around
0
0
1
1
Figure 17. Set Burst with Wrap Instruction Sequence
Yes
Yes
Yes
Yes
Instruction (
Instruction (
2
2
W4 = 0
3
3
4
4
77h
77h
Wrap Length
)
)
5
5
16-byte
32-byte
64-byte
8-byte
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6
6
7
7
don’t care don’t care don’t care
don’t care don’t care don’t care
X
X
X
X
X
X
X
X
X
X
X
X
8
8
X
X
X
X
X
X
X
X
X
X
X
X
Wrap Around
9
9
X
X
X
X
X
X
X
X
X
X
X
X
10
10
No
No
No
No
W4 =1 (default)
X
X
X
X
X
X
X
X
X
X
X
X
11
11
X
X
X
X
X
X
X
X
X
X
X
X
12
12
X
X
X
X
X
X
X
X
X
X
X
X
13
13
Wrap Length
w4
w4
w4
w5
w5
w5
w6
w6
w6
X
X
X
wrap bit
wrap bit
14
14
W25Q40BV
N/A
N/A
N/A
N/A
X
X
X
X
X
X
X
X
X
X
X
X
15
15