An ARM Assembly developer works on low-level programming for devices using the ARM processor. They write, debug, and test assembly language programs, ensuring optimal performance and efficiency. Their work involves direct manipulation of hardware, registers, and memory, requiring a deep understanding of system architecture. They often take high-level language code and translate it into assembly for fine-tuning. This role also involves understanding timing issues and power consumption, crucial for mobile devices and embedded systems. The developer may also contribute to hardware design, system troubleshooting, and the creation of real-time operating systems.