Page 258 - Mechatronics with Experiments

244 MECHATRONICS
3. How many hardware interrupt priorities are supported in the PIC 18F452? Describe how these
interrupts are enabled/disabled, how an interrupt is handled, and the sequence of events that occurs
in the microcontroller when an interrupt event occurs.
4. List the input/output (I/O) ports available on the PIC 18F452 microcontroller. Give examples of
C-code to show how they are setup and used in a real-time application software.
5. What is the role of capture/compare/PWM port on the PIC 18F452 microcontroller? Describe
how this port is setup and used in different applications.
6. Discuss the differences between “polling driven” versus “interrupt driven” programming. Give
examples for polling driven and interrupt driven applications. What are the internal and external
interrupt sources to the microcontroller?
7. Discuss analog and digital converter (ADC) inputs available on the PIC 18F452 chip: how
many channels, resolution of each channel, multiplexed or not, how ADC operation is controlled in
software.
8. PWM input and output signals are often converted to analog voltage signals using low-pass
®
filters. Design and simulate the following in Simulink : a PWM signal source with 1 KHz base
frequency and adjustable pulse-width modulation (PWM source), an analog filter with time constant
of 0.01 s. Simulate the input and output of the low pass filter for a PWM duty cycle of 25, 50, and
100% the low pass filter transfer function is
1
D(s) = (4.8)
0.01 s + 1