Software-defined device interface system and method

A software-defined device interface system which includes:

• a microprocessor with a plurality of general purpose input/output (GPIO) pins;
• and
• software/firmware which is configured, based on a specific communication protocol which is used by a particular external device for communication purposes, to, in runtime,
• assign/select one or more of the GPIO pins to form a virtual port to which the particular external device can be connected, upon receiving a configuration instruction from a user to implement the specific communication protocol, and
• implement the specific communication protocol through the virtual port by emulating signals defined in a protocol specification of the specific communication protocol on the GPIO pins that form the virtual port, to thereby allow for communication between the microprocessor and the external device, when the external device is connected to the pin(s) of the virtual port,
• wherein the system further includes a voltage switching circuit which is connectable between the GPIO pins that form the virtual port and the external device, and which is operable to convert between a TTL (transistor-transistor logic) or CMOS (Complementary metal-oxide-semiconductor) voltage level that represents a logic 0 on the GPIO pins that form the virtual port and a voltage level that represents a logic 0 on a communication interface of the external device, and to convert between a TTL or CMOS voltage level that represents a logic 1 on the GPIO pins that form the virtual port and a voltage level that represents a logic 1 on the communication interface of the external device,
• wherein the voltage switching circuit has at least two programmable settings that are selectable by the microprocessor to set the voltage levels that respectively represent a logic 0 and 1 on the communication interface of the external device,
• and wherein the specific communication protocol is selectable from the group consisting of at least MODBUS RTU over RS-485, MODBUS RTU over RS-232, Universal Asynchronous Receiver-Transmitter (UART) over RS-485, UART over RS-232, Serial Peripheral Interface (SPI), inter-integrated circuit (I2C), Controller Area Network (CAN) bus, and Wiegand.