Using the ARM Cortex-M4 and the CMSIS-DSP library for teaching real-time DSP

In this paper we describe experiences working with the Cortex-M4 microcontroller in a graduate/senior elective real-time DSP course. Previously the same course used dedicated DSP processors, but the invitation from the ARM University Program to try out a new Lab-in-a-box (LiB) kit for teaching real-time DSP was intriguing. The hardware is inexpensive, costing only $50, thus allowing students to buy their own boards. The LiB comes with teaching materials, but beyond the use of the audio codec software library, essentially all of this new course was developed by rewriting teaching materials from a previous course, and making extensive changes to adapt to the new software and hardware. Of particular interest is CMSIS-DSP, the Cortex-M Software Interface Standard (CMSIS) DSP library, which contains over 60 DSP algorithms in both fixed-point and floating-point. By using this library students become familiar with the Misra C coding standard, and software re-use. Developing algorithms in C from scratch is still needed and encouraged. When writing a custom filter algorithm for example, the students can benchmark against one or more CMSIS-DSP library algorithms. The Digilent Analog™Discovery PC-based instrumentation and the use of IPython notebook were also added into the new course.