Arbitrary waveform generators (AWGs) are very expensive instruments useful for generating complex signals and waveforms needed as communication and test signals for state of the art communication, Internet of Things (IoT), and Cyber Physical Systems (CPS) devices. In recent years, research has been directed towards making powerline communication (PLC) feasible as a last mile communication network for IoT, smart grid (SG) and CPS. This paper present results of using a low-cost PLC modem (Texas Instrument's TMS320C2000 C28x) and embedded C programming language as an AWG to generate test signals for PLC, SG, IoT and CPS research purposes. Our implementation is the first known application of the TMS320C2000 C28x as an AWG. Using embedded C language makes the waveforms generated platform independent, and thus, avoids the use of platform dependent hexadecimal assembly languages. This method also overcomes the rigid amplitude problem of the Direct Digital Synthesis (DDS) technique. The core embedded signal processor used in this paper is the low-cost TMS320C2000 C28x which is widely deployed in many IoT, CPS, industrial systems and communication networks devices worldwide. It has 16-bit resolution at 100 kHz bandwidth. Several examples of industrial grade arbitrary waveforms were constructed for the TMS320C2000 C28x with the embedded C programming technique. Hence arbitrary signals generated using the C28x will be useful in testing many state of the art and legacy communication, IoT, SG, and CPS networks and devices worldwide. In addition to signal generation, examples are shown of using the arbitrary waveforms generated with TMS320C2000 to implement amplitude modulation (AM) and pulse amplitude modulation (PAM) schemes for CPS, IoT and PLC communication networks.