In a preemptive priority based RTOS, priority inversion

problem is among the major sources of deadline

violations. Priority inheritance protocol is one of the

approaches to reduce priority inversion. Unfortunately,

RTOS like uC/OS can’t support priority inheritance

protocol since it does not allow kernel to have multiple

tasks at the same priority. Although it has different ways

to avoid priority inversion such as priority ceiling

protocol, developers still have some difficulties in

programming real time applications with it. In this paper,

we redesign the uC/OS kernel to provide the ability to

support round robin scheduling and implement priority

inheritance semaphore on the modified kernel. As result,

we port new kernel with priority inheritance semaphore to

evaluation board, and evaluate the execution time of each

of the kernel service as well as verify the operations of

our implementation.