GD25Q32CxIGx 3.3V Uniform Sector Dual and Quad Serial Flash
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7.9. Quad Output Fast Read (6BH)
The Quad Output Fast Read command is followed by 3-byte address (A23-A0) and a dummy byte, each bit
being latched in during the rising edge of SCLK, then the memory contents are shifted out 4-bit per clock cycle
from IO3, IO2, IO1 and IO0. The command sequence is shown in followed Figure10. The first byte addressed
can be at any location. The address is automatically incremented to the next higher address after each byte of
data is shifted out.
Figure 10. Quad Output Fast Read Sequence Diagram
CS#
0
1
2
3
4
5
6
7
8
9 10
28 29 30 31
SCLK
Command
6BH
24-bit address
23 22 21
SI(IO0)
3
2
1
0
SO(IO1)
High-Z
High-Z
High-Z
WP#(IO2)
HOLD#(IO3)
CS#
32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
Dummy Clocks
SCLK
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
SI(IO0)
SO(IO1)
WP#(IO2)
HOLD#(IO3)
Byte1 Byte2 Byte3 Byte4
7.10. Dual I/O Fast Read (BBH)
The Dual I/O Fast Read command is similar to the Dual Output Fast Read command but with the capability
to input the 3-byte address (A23-0) and a “Continuous Read Mode” byte 2-bit per clock by SI and SO, each bit
being latched in during the rising edge of SCLK, then the memory contents are shifted out 2-bit per clock cycle
from SI and SO. The command sequence is shown in followed Figure11. The first byte addressed can be at any
location. The address is automatically incremented to the next higher address after each byte of data is shifted
out.
Dual I/O Fast Read with “Continuous Read Mode”
The Dual I/O Fast Read command can further reduce command overhead through setting the “Continuous
Read Mode” bits (M7-4) after the input 3-byte address (A23-A0). If the “Continuous Read Mode” bits (M5-4)
=(1, 0), then the next Dual I/O Fast Read command (after CS# is raised and then lowered) does not require the
BBH command code. The command sequence is shown in followed Figure12. If the “Continuous Read Mode”
bits (M5-4) do not equal (1, 0), the next command requires the first BBH command code, thus returning to
normal operation. A “Continuous Read Mode” Reset command can be used to reset (M5-4) before issuing
normal command.
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