w25q32bw Winbond Electronics Corp America, w25q32bw Datasheet - Page 32

• Manufacturer Part Number: w25q32bw
• Description: 32m-bit 1.8v Serial Flash Memory With Dual And Quad Spi
• Manufacturer: Winbond Electronics Corp America

10.2.15 Word Read Quad I/O (E7h)
The Word Read Quad I/O (E7h) instruction is similar to the Fast Read Quad I/O (EBh) instruction except
that the lowest Address bit (A0) must equal 0 and only two Dummy clock are required prior to the data
output. The Quad I/O dramatically reduces instruction overhead allowing faster random access for code
execution (XIP) directly from the Quad SPI. The Quad Enable bit (QE) of Status Register-2 must be set to
enable the Word Read Quad I/O Instruction. To ensure optimum performance the High Performance
Mode (HPM) instruction (A3h) must be executed once, prior to the Fast Read Quad I/O Instruction.
Word Read Quad I/O with “Continuous Read Mode”
The Word Read Quad I/O instruction can further reduce instruction overhead through setting the
“Continuous Read Mode” bits (M7-0) after the input Address bits (A23-0), as shown in figure 14a. The
upper nibble of the (M7-4) controls the length of the next Fast Read Quad I/O instruction through the
inclusion or exclusion of the first byte instruction code. The lower nibble bits of the (M3-0) are don’t care
(“x”). However, the IO pins should be high-impedance prior to the falling edge of the first data out clock.
If the “Continuous Read Mode” bits M5-4 = (1,0), then the next Fast Read Quad I/O instruction (after /CS
is raised and then lowered) does not require the E7h instruction code, as shown in figure 14b. This
reduces the instruction sequence by eight clocks and allows the Read address to be immediately entered
after /CS is asserted low. If the “Continuous Read Mode” bits M5-4 do not equal to (1,0), the next
instruction (after /CS is raised and then lowered) requires the first byte instruction code, thus returning to
normal operation. A “Continuous Read Mode” Reset instruction can also be used to reset (M7-0) before
issuing normal instructions (See 10.2.19 for detail descriptions).
Figure 14a. Word Read Quad I/O Instruction Sequence (Initial instruction or previous M5-4
Instruction (E7h)
Instruction (E7h)
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4
4
4
5
5
5
6
6
6
7
7
7
Byte 1
Byte 1
0
0
0
1
1
1
2
2
2
3
3
3
Byte 2
Byte 2
4
4
4
5
5
5
6
6
6
7
7
7

10)
0
0
0
1
1
1
2
2
2
3
3
3
W25Q32BW
Byte 3
Byte 3
4
4
4
5
5
5
6
6
6
7
7
7
0
0
0
1
1
1
2
2
2
3
3
3