w25q16bv Winbond Electronics Corp America, w25q16bv Datasheet - Page 50

• Manufacturer Part Number: w25q16bv
• Description: 16m-bit Serial Flash Memory With Dual And Quad Spi
• Manufacturer: Winbond Electronics Corp America

10.2.32 Continuous Read Mode Reset (FFh or FFFFh)
For Fast Read Dual/Quad I/O operations, “Continuous Read Mode” Bits (M7-0) are implemented to
further reduce instruction overhead. By setting the (M7-0) to “Ax” hex, the next Fast Read Dual/Quad I/O
operation does not require the BBh/EBh/E7h/E3h instruction code (See 10.2.13 - 10.2.16 for detail
descriptions).
If the system controller is Reset during operation it will likely send a standard SPI instruction, such
as Read ID (9Fh) or Fast Read (0Bh), to the W25Q16BV. However, as with most SPI Serial Flash
memories, the W25Q16BV does not have a hardware Reset pin, so if Continuous Read Mode bits are set
to “Ax” hex, the W25Q16BV will not recognize any standard SPI instructions. To address this possibility, it
is recommended to issue a Continuous Read Mode Reset instruction as the first instruction after a
system Reset. Doing so will release the Continuous Read Mode from the “Ax” hex state and allow
Standard SPI instructions to be recognized. The Continuous Read Mode Reset instruction is shown in
figure 31.
To reset “Continuous Read Mode” during Quad I/O operation, only eight clocks are needed. The
instruction is “FFh”. To reset “Continuous Read Mode” during Dual I/O operation, sixteen clocks are
needed to shift in instruction “FFFFh”.
/CS
/CS
CLK
CLK
IO
IO
IO
IO
IO
IO
IO
IO
0
0
1
1
2
2
3
3
Mode 3
Mode 3
Mode 0
Mode 0
Figure 31. Continuous Read Mode Reset for Fast Read Dual/Quad I/O
0
0 0
1
1 1
Mode Bit Reset
Mode Bit Reset
for Quad I/O
for Quad I/O
2
2 2
3
3 3
FFh
FFh
4
4 4
5
5 5
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6
6 6
Don’t Care
Don’t Care
Don’t Care
Don’t Care
Don’t Care
Don’t Care
7
7 7
8
8 8
9
9 9
10
10
10
11
11
11
FFh
FFh
12
12
12
Mode Bit Reset
Mode Bit Reset
for Dual I/O
for Dual I/O
13
13
13
14
14
14
15
15
15
W25Q16BV
Mode 3
Mode 3
Mode 0
Mode 0