Research And Implementation Of Hardware Based Real Time Task Scheduler

With the rapid development of processor technology,heterogeneous multi-core processors have gradually become the mainstream due to their specificity.However,among heterogeneous multi-core processors,how to coordinate the work among these processors and run tasks reasonably becomes the key.In embedded systems with very limited resources,heterogeneous multi-core chips integrated by chip manufacturers communicate with each other through on-chip buses.However,it cannot fully meet the increasingly complex and diverse resource management requirements.The system functions can only be realized through different chip combinations,and how to coordinate the work of these processors with different architectures is a difficult problem.Aiming at the above problems,this thesis designs a hardware-based real-time task scheduler.The logic circuit built by FPGA is used to realize the scheduling function.Task scheduling is based on priority,and round-robin scheduling based on time slices is used for the same priority.In order to be able to connect two or more processors,this paper uses the characteristics of parallel design of gate circuits to build a scheduler by grouping processors and tasks.In addition,this paper also designs and implements commonly used semaphores,mutexes,timers and other modules in hardware to help the scheduler realize task synchronization and mutual exclusion,and hardware mutexes can also reduce priority conflicts.Turn problems occur,forming a complete hardware real-time task scheduler.The scheduler can complete scheduling commands in one clock cycle.In this paper,the VHDL language is used to build the real-time task scheduler in a modular way,and the configuration file can be changed according to the requirements before compiling,which has the same portability and tailorability as the software real-time operating system.If there is direct communication between the hardware real-time task scheduler and the processor,a lot of I/O ports will be wasted,so this paper also uses VHDL language to design a dedicated communication protocol interface.According to different communication methods,it is divided into on-chip communication interface and off-chip communication interface.The processor can send data and commands to the task scheduler through this interface.When task scheduling is required,the task scheduler will notify the processor to switch the specified task through an interrupt.Finally,the function simulation and power-on test of the hardware-based real-time task scheduler are carried out to verify the correctness and feasibility of the system.