GD25Q16C Datasheet, PDF (31/49 Pages) ELM Electronics – 16M-bit Serial Flash

GD25Q16CxIGx 3.3V Uniform Sector Dual and Quad Serial Flash
7.24. Continuous Read Mode Reset (CRMR) (FFH)
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The Dual/Quad I/O Fast Read operations, “Continuous Read Mode” bits (M7-0) are implemented to further
reduce command overhead. By setting the (M7-0) to AXH, the next Dual/Quad I/O Fast Read operations do not
require the BBH/EBH/E7H command code.
Because the GD25Q16C has no hardware reset pin, so if Continuous Read Mode bits are set to “AXH”, the
GD25Q16C will not recognize any standard SPI commands. So Continuous Read Mode Reset command will
release the Continuous Read Mode from the “AXH” state and allow standard SPI command to be recognized.
The command sequence is show in Figure29.
Figure 29. Continuous Read Mode Reset Sequence Diagram
CS#
SCLK
Mode Bit Reset for Quad/Dual I/O
01234567
SI(IO0)
SO(IO1)
WP#(IO2)
HOLD#(IO3)
FFH
Don`t Care
Don`t Care
Don`t Care
7.25. Read Unique ID (4BH)
The Read Unique ID command accesses a factory-set read-only. 64bit number that is unique to each
GD25Q16C device. The Unique ID can be used in conjunction with user software methods to help prevent
copying or cloning of a system. The Read Unique ID command sequence: CS# goes low → sending Read
Unique ID command → Dummy Byte1 → Dummy Byte2 → Dummy Byte3 → Dummy Byte4 → 64bit Unique
ID Out → CS# goes high. The command sequence is show below.
Figure 30. Read Unique ID Sequence Diagram
CS#
SCLK
01234567 89
36 37 38 39 40
101 102 103
Command(4BH)
4byte Dummy
SI
SO
High-Z
64bit Unique ID
63
210
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Rev.1.1