FOR MOBILE APPLICATIONS
W25Q256FV
- 59 -
8.2.24
Set Burst with Wrap (77h)
In Standard SPI mode, 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 24/32 dummy bits and 8 “Wrap Bits”, W7-0. The
instruction sequence is shown in Figure 28. Wrap bit W7 and the lower nibble W3-0 are not used.
W6, W5
W4 = 0
W4 =1 (DEFAULT)
Wrap Around
Wrap Length
Wrap Around
Wrap Length
0 0
Yes 8-byte No N/A
0 1
Yes 16-byte No N/A
1 0
Yes 32-byte No N/A
1 1
Yes 64-byte No N/A
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 or after a
software/hardware reset is 1.
In QPI mode, the “Burst Read with Wrap (0Ch)” instruction should be used to perform the Read operation
with “Wrap Around” feature. The Wrap Length set by W5-4 in Standard SPI mode is still valid in QPI mode
and can also be re-configured by “Set Read Parameters (C0h)” instruction. Refer to 8.2.44 and 8.2.45 for
details.
Wrap Bit
/CS
CLK
Mode 0
Mode 3
0
1
IO
0
IO
1
IO
2
IO
3
2
3
4
5
X
X
X
X
X
X
X
X
don't
care
6
7
8
9
don't
care
don't
care
10
11
12
13
14
15
Instruction (77h)
Mode 0
Mode 3
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
w4
X
w5
X
w6
X
X
X
Figure 28. Set Burst with Wrap Instruction (SPI Mode only)
32-Bit dummy bits are required when the device is operating in 4-Byte Address Mode