Configuring the Switch Matrix has been made easy through a simplified design. The Switch Matrix has a dedicated clock source that allows the ability to change the configurations to be gated through enabling or disabling the source. Enabling the clock source allows pin function assignment registers to be read or written. When the clock is disabled, the assignments are locked and cannot be changed; also power through the circuit is removed, allowing energy savings. Each assignable function has one register which controls the configuration, the PINASSIGN register. An array of PINASSIGN registers exists in order to accommodate all moveable functions. Each microcontroller defines the default configuration of each port pin. Usually, port pins are configured as general purpose input/output ports without peripheral functions assigned. Devices with serial-wire debug or JTAG ports exposed will have these important debug functions enabled to allow software development and download. As with all electronic design, care must be exercised when assigning pin functions so that a conflict does not occur between peripherals, or with the debug controller.