The invention discloses an enhanced SPI (serial
peripheral interface) controller, a communication
system of the enhanced SPI and a
data transmission method, and mainly aims at solving the problem that the existing SPI
bus cannot actually realize full duplex. In the invention, a sending control state
machine and a receiving control state
machine are added to the existing SPI controller, wherein the sending control state
machine independently controls the data sending of the enhanced SPI controller by sending a write
signal; the receiving control state machine independently controls the data reception of the enhanced SPI controller through a read
signal; or two control signals are added to the existing SPI interface method, namely a read
signal RD# and a write signal WR#, and the sampling of an SDI signal and the sampling of an SDO signal of the SPI interface are triggered by the two signals, being equivalent to two independent state machines controlling the read and write. Through the enhanced SPI controller, the communication
system of the enhanced SPI and the
data transmission method, real full-duplex communication and high-speed
data access are supported, and the
control software is relatively easy to realize and convenient to transplant; and the enhanced SPI controller, the communication
system of the enhanced SPI and the
data transmission method are particularly suitable for the data communication between a high-speed MODEM (modulator-demodulator) and an AP (access point).