GD25LQ40xIGx 1.8V Uniform Sector Dual and Quad Serial Flash
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Quad I/O Fast Read with “Continuous Read Mode”
The Quad I/O Fast Read command can further reduce command overhead through setting the “Continuous
Read Mode” bits (M7-0) after the input 3-byte address (A23-A0). If the “Continuous Read Mode” bits (M5-4)
= (1, 0), then the next Quad I/O Fast Read command (after CS# is raised and then lowered) does not require the
EBH command code. The command sequence is shown in followed Figure12a. If the “Continuous Read Mode”
bits (M5-4) do not equal to (1, 0), the next command requires the first EBH command code, thus returning
to normal operation. A “Continuous Read Mode” Reset command can be used to reset (M5-4) before issuing
normal command.
Figure 12. Quad I/O Fast Read Sequence Diagram (M5-4 ≠ (1, 0))
CS#
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
SCLK
Command
EBH
SI(IO0)
4
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
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
SO(IO1)
5
6
7
WP#(IO2)
HOLD#(IO3)
A23-16 A15-8 A7-0 M7-0
Dummy
Byte1 Byte2
Figure 12a. Quad I/O Fast Read Sequence Diagram (M5-4 = (1, 0))
CS#
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15
SCLK
SI(IO0)
4
0
4
0
4
0
4
0
4
5
6
7
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
SO(IO1)
5
6
7
1
2
3
5
6
7
1
2
3
5
6
7
1
2
3
5
6
7
1
2
3
WP#(IO2)
HOLD#(IO3)
A23-16 A15-8 A7-0 M7-0
Dummy
Byte1 Byte2
Quad I/O Fast Read with “8/16/32/64-Byte Wrap Around” in Standard SPI mode
The Quad I/O Fast Read command can be used to access a specific portion within a page by issuing “Set Burst
with Wrap” (77H) commands prior to EBH. The “Set Burst with Wrap” (77H) command can either enable or
disable the “Wrap Around” feature for the following EBH commands. When “Wrap Around” is enabled, the
data being accessed can be limited to either an 8/16/32/64-byte section of a 256-byte page. The output data
starts at the initial address specified in the command, once it reaches the ending boundary of the 8/16/32/64-byte
section, the output will wrap around the beginning boundary automatically until CS# is pulled high to terminate
the command.
Rev.1.0
59 - 24
ELM [ ELM ELECTRONICS ]
