A graphical software tool with integer linear programming for microcontroller input/output interface selection feasibility

This paper describes a graphical and interactive software tool to support embedded systems engineering with highly integrated microcontrollers such as the ColdFire MCF54418. Such products have many input/output interfaces that share chip pins, hence not all possible combinations of active interfaces are feasible due to pin conflicts. To address challenges stemming from such conflicts, the software tool described in this paper provides early decision support for selection and subsequent hardware configuration of interfaces. An XML input file describes pins and interfaces of a microcontroller. From this information, the software tool generates an interactive graphical representation for a designer to interactively explore interfaces and pins, to visualize interface conflicts due to shared pins, and to incrementally develop conflict-free interface combinations. More importantly, the tool provides higher-level automated decision support with integer linear programming to solve an optimization problem and conclusively determine whether there exists a feasible conflict-free selection for given specifications on desired types and numbers of interfaces. Finally, for general-purpose input/output, the tool also has a more specialized mode that enables a user to indicate application-specific grouping and direction of pins. From this information, the tool automatically tailors an application programming interface in C code.