A few signal naming conventions are used throughout the example program. It helps to familiarize yourself with them before delving further into the logic and signal flow of the program.
A button press signal from a touch panel output has the _Button suffix at the end of its name. A button feedback signal to a touch panel input has the _fb suffix at the end of its name. Take the Wall Open button that appears on the XPanel for example. The signal from its press2 output is named Wall_Toggle_Button and the signal to its fb2 input is named Wall_Toggle_ON_fb.
The _ON and _Off substrings appear in the names of some of the digital signals used for toggles. A toggle button press could be turning a toggle on or off depending on its previous state. A press signal is transient so other signals are needed to capture and maintain the toggle’s state. When a signal with an _ON suffix goes high that always indicates a toggle ON event. When a signal with an _Off suffix goes high that always indicates a toggle Off event.
Several touch panel button press signals have a _Radio_Button suffix at the end of their name. The suffix is intended for radio buttons that operate together as members of a group. Take the Source selector group of radio buttons on the XPanel for example. If the Classical radio button is selected then the Jazz and Reggae radio buttons must be deselected. Because they are so closely related the signals for radio buttons belonging to the same group are arranged close to one another throughout the program.
A _sel substring is used in digital signal names to indicate that signal is part of a selector. It takes the place of the Radio_Button suffix in selector signals that aren’t driven by the touch panel. Take the Source selector as an example. The Serial I/O has outgoing CLASSICAL_sel, JAZZ_sel and REGGAE_sel signals for the three different source selector positions that can come from Halogen/HAL. The _sel substring also appears in the names of certain toggle signals. In that context the toggle is viewed as a 2-way selector with a toggle ON selection and a toggle Off selection.