Hardware Real-time Event Management with Support of RISC-V Architecture for FPGA-Based Reconfigurable Embedded Systems

Task context switching, unitary management of events, synchronization and communication mechanisms are significant problems for each real-time operating system. For real-time systems, another overhead factor is the processor's time to execute the routine of treating external asynchronous interrupts. The main objective of this paper is to describe, implement, and validate the preemptive scheduler module as part of the hardware accelerated real-time operating system, using the RISC-V instruction set and Verilog HDL. The new architecture contains the hardware structure used for static and dynamic scheduling of the tasks, real-time management of the events, and also defines a method used to attach interrupts to tasks. In order to accomplish this objective, it was necessary to structure CPU modules so as to ensure easy adaptation to other implementations (MIPS coprocessor, ARM or RISC-V).