There was no operating system with threading and a scheduler for Wixel. Therefore, we ported RIOT-OS to the MCS51 architecture featured on the Wixel. I have included a scheduler, threads, and a POSIX-compliant API for a subset of the supported functions. We use the SDCC version 3.6.0 toolchain for our implementation, that only fully supports C89 for the MCS51 architecture, whereas RIOT-OS is written for C11 and GCC toolchains. I describe how code is stored in memory and how memory allocations are done. Then I go into how memory size restrictions and the instruction architecture of the Wixel complicated this development.