Chapter 4. CPU Operation
GFK-2222AD
April 2018
141
4.1.1
Parts of the CPU Sweep
There are seven major phases in a typical CPU sweep as shown in the following figure.
Prog
window
scheduled
?
no
yes
Communications
Controller
Window
Comm
window
scheduled
?
yes
no
Backplane
Communications
Window
Start next sweep
SWEEP
Background
task
scheduled
?
Background task
Window
yes
no
Application Program
Task Execution
(Logicwindow)
WINDOW
)
Start-of-Sweep
Housekeeping
input scan
Output Scan
Figure 40: Major Phases of a Typical CPU Sweep