The QuadSPI(Quad Serial Peripheral Interface) acts as an interface to
one single or two external serial flash devices, each with up to 4
bidirectional data lines.
(1) The QuadSPI controller is driven by the LUT(Look-up Table) registers.
The LUT registers are a look-up-table for sequences of instructions.
A valid sequence consists of four LUT registers.
(2) The definition of the LUT register shows below:
There are several types of INSTRx, such as:
CMD : the SPI NOR command.
ADDR : the address for the SPI NOR command.
DUMMY : the dummy cycles needed by the SPI NOR command.
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There are several types of PADx, such as:
PAD1 : use a singe I/O line.
PAD2 : use two I/O lines.
PAD4 : use quad I/O lines.
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