Cyclic executives for Bare Hardware Chapter 4

Topics Simple loop cyclic executive Frame/slots Table-based predetermined schedule cyclic executive Periodic, aperiodic and interrupt-based task

The basic systems Several functions are called in a prearranged sequence Some kind of cooperative scheduling You a have a set of tasks and a scheduler that schedules these tasks Types of tasks: base tasks (background), interrupt tasks, clock tasks Frame of slots, slots of cycles, each task taking a cycle, burn tasks to fill up the left over cycles in a slot.

Blind Bingo Display(); Read input(); Loop: A c b g k update display(); If all done exit(); End Loop; A c b g k V n m L s E t y w f D v z x e

Frame/slot/cycle pre-determined schedule Example Your week is frame of 7 slots, each with 24 cycles. it repeats itself Lets look at a demo program

Lets analyze the sample program Change task times Lets analyze repetition rate of the tasks and how it relates to the task table