Software is used to allow inputs to a microcontroller to have primary and alternate functions, which reduces the need for additional inputs and associated conductors in a programmable device such as a warning signal light. The microcontroller firmware includes a routine that detects the state of inputs during a first predetermined period of time after initialization of the microcontroller. The state of the inputs is used to activate alternate modes of operation in which changes in the state of the inputs is detected and used for functions different than a function associated with the same input in another mode of operation.