Educational applications and benefits of a compact multitasking kernel for microcontrollers

This paper describes the educational applications and benefits of a compact multitasking kernel for Motorola 68HC11 and 68HC12 microcontroller-based systems used in teaching at Queen's University. The kernel is implemented in assembly language and in C; neither version exceeds 200 lines of code. The base kernel enables students to apply their knowledge of both microprocessor systems and operating systems by adding new services and writing code to test those services. The most interesting application, however; is the use of a speech chip to audibly trace the dynamic execution of the kernel. Prerecorded voice messages are played back at strategic points to identity key events and conditions. This capability can also serve as a debugging aid when adding new services to the kernel.