👉 The Deny I/O (DIO) instruction is a low-level system call used primarily in embedded systems and microcontrollers to control input/output operations at the hardware level, bypassing the operating system's interrupt handling mechanisms. When executed, DIO allows a processor to directly read from or write to external devices without going through the normal I/O request and response cycle managed by the CPU and I/O controllers. This direct access is crucial for real-time systems where predictable and low-latency responses are essential, as it enables faster data handling and reduces overhead associated with context switching and interrupt service routines. DIO is particularly useful for interfacing with peripherals like sensors, memory modules, and communication interfaces that require immediate interaction.
