User`s guide

1 Getting Started
1-4
Features
The Real-Time Windows Target software environment includes many features
to help you prototype and test real-time applications.
This section includes the following topics:
• “Real-Time Kernel” on page 1-4
• “Real-Time Application” on page 1-5
• “Signal Acquisition and Analysis” on page 1-6
• “Parameter Tuning” on page 1-7
Real-Time Kernel
The Real-Time Windows Target uses a small real-time kernel to ensure that
the real-time application runs in real time. The real-time kernel runs at CPU
ring zero (privileged or kernel mode) and uses the built-in PC clock as its
primary source of time:
•
Timer interrupt — The kernel intercepts the interrupt from the PC clock
before the Windows operating system receives it. This blocks any calls to the
Windows operating system. Because of this, you cannot use Win32 calls in
your C-code S-function.
The kernel then uses the interrupt to trigger the execution of the compiled
model. As a result, the kernel is able to give the real-time application the
highest priority available.
To achieve precise sampling, the kernel reprograms the PC clock to a higher
frequency. Because the PC clock is also the primary source of time for the
Windows operating system, the kernel sends a timer interrupt to the
operating system at the original interrupt rate.
Technically, the kernel is provided as a kernel-mode driver on Windows
2000, Windows NT, and Windows XP.