Onboard electronic equipment I/O port expansion system

The invention discloses an airborne electronic equipment I/O port expansion system, and aims to provide a scheme which can utilize external interface resources of a processor to the maximum extent and ensure that the system has an IO expansion function on the premise that a programmable logic device is not used. According to the technical scheme, a processor is connected with an IO expander through an integrated circuit bus IIC. An IO interface, needing to be expanded, of a system is connected to a port end of an IO expander, a read-write control command is sent to the IO expander, output and read of ports of the multiple IO expanders are achieved, the data transmission direction of corresponding ports at the two ends of a bus transceiver is determined, the IO expander is made to be matched with the signal data flow direction in the bus transceiver, and the data transmission speed of the bus transceiver is increased. Through interaction between the bus transceiver and external airborne electronic equipment, i