Find an algorithmic state machine (ASM) chart for a traffic light controller that works as follows: A timing signal T is the input to the controller. T defines the yellow light interval, as well as the changes of the red and green lights.
The outputs to the signals are defined by the following table:Output
Light Controlled
GN
Green Light, North/south Signal
YN
Yellow Light, North/south Signal
RN
Red Light, North/south Signal
GE
Green Light, East/west Signal
YE
Yellow Light, East/west Signal
RE
Red Light, East/west Signal
While T = 0, the green light is on for one signal and the red light for the other. With T = 1, the yellow light is on for the signal that was previously green, and the signal that was previously red remains red.
When T becomes 0, the signal that was previously yellow becomes red, and the signal that was previously red becomes green.
This pattern of alternating changes in color continues.
Assume that the controller is synchronous with a clock that changes much more frequently than input T.