An input/output module includes a multiplexing circuit, which is responsive to a plurality of I/O signals and configured to output a selected one of the plurality of I/O signals according to a value of a common input signal received at a control terminal thereof. A level shifting circuit is provided, which is configured to convert a voltage level of the selected one of the plurality of I/O signals and a voltage level of the common input signal. At least two functional blocks are provided, which are each configured to receive the selected one of the plurality of I/O signals having the converted voltage level, yet operate in a mutually exclusive manner according to a value of the common input signal having the converted voltage level.