The GD25Q40C(4M-bit)Serial flash supports the standard Serial Peripheral Interface(SPI), and supports theDual/Quad SPI:Serial Clock, Chip Select, Serial Data I/O0(SI), I/O1(SO), I/O2(WP#), and I/O3(HOLD#). The Dual I/O data is transferred with speed of 240Mbits/s and the Quad I/O & Quad output data is transferred with speed of 480Mbits/s.