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Microcontroller Programming and Interfacing Texas Instruments MSP430 by Daniel J. Pack, Steven F. Barrett

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360 10. SYSTEM LEVEL DESIGN
10.8 CHAPTER PROBLEMS
1. For the SeaPerch ROV provide adjustable speed control for each motor. This advanced feature
requires several modifications including a proportional joystick and pulse width modulation
signals to the motor. The joystick currently in use provides a simple on and off signal. A
proportional joystick provides an X and Y output DC signal proportional to the joystick
deflection on each axis. These signals may be fed to the analog-to-digital converter aboard
the MSP430. The X and Y signals captured from the joystick may be used to provide a pulse
width modulated signal with a duty cycle proportional to deflection.
2. For the SeaPerch ROV provide a powered dive and surface thruster.The current control system
provides a powered drive capability with the vertical thruster. The ROV returns to the surface
using its slightly positive buoyancy. To provide for a powered dive and surface capability, the
vertical thruster must be equipped with an H-bridge to allow for motor forward and reversal.
3. For the SeaPerch ROV provide left and right thruster reverse. Currently, the left and right
thrusters may only be powered in one direction.To provide additional maneuverability, the left
and right thrusters could be equipped with an H-bridge to allow bi-directional motor control.
4. For the SeaPerch ROV provide proportional speed control with bi-directional motor control.
Both of these advanced features may be provided by driving the H-bridge circuit with PWM
signals.
5. Construct the UML activity diagrams for all functions related to the weather station.
6. It is desired to updated weather parameters every 15 minutes. Write a function to provide a
15 minute delay.
7. Add one of the following sensors to the weather station:
anemometer
barometer
hygrometer
rain gauge
thermocouple
You will need to investigate background information on the selected sensor,develop an interface
circuit for the sensor, and modify the weather station code.
8. Modify the weather station software to also employ the 138 x 110 LCD. Display pertinent
weather data on the display.
10.8. CHAPTER PROBLEMS 361
9. Equip the weather station with an MMC/SD flash memory card. Note:Texas Instruments has
a very detailed Application Report, Interfacing the MSP430 with MMC/SD flash memory
card [slaa281b]” that describes the required Serial Peripheral Interface (SPI) configuration
and software library.
10. Modify the motor speed control circuit interface to provide for bi-directional motor control.
11. Use optical encoder output channels A and B to determine motor direction and speed.
12. Modify the motor speed control algorithm to display motor direction (CW or CCW) and
speed in RPM on the LCD.
13. The Blinky 602A robot under microcontroller control abruptly starts and stops when PWM
is applied. Modify the algorithm to provide the capability to gradually ramp up (and down)
the motor speed.
14. Modify the Blinky 602A circuit and microcontroller code such that the maximum speed of
the robot is set with an external potentiometer.
15. Modify the Blinky 602A circuit and microcontroller code such that the IR sensors are only
asserted just before a range reading is taken.
16. Apply embedded system design techniques presented throughout the text to a project of your
choosing. Follow the design process and provide the following products:
system description,
system requirements,
a structure chart,
system circuit diagram,
UML activity diagrams, and the
microcontroller code.
17. Add the following features to the Blinky 602A platform:
Line following capability (Hint: Adapt the line following circuitry onboard the Blinky
602A to operate with the MSP430.)
Two way robot communications (use the IR sensors already aboard)
LCD display for status and troubleshooting display
Voice output (Hint: Use an ISD 4003 Chip Corder.)
18. Develop an embedded system controlled submarine (www.seaperch.org).
362 10. SYSTEM LEVEL DESIGN
19. Equip the MSP430 with automatic cell phone dialing capability to notify you when a fire is
present in your home.
20. Develop an embedded system controlled dirigible/blimp (www.microflight.com,
www.rctoys.com).
21. Develop a trip odometer for your bicycle (Hint: use a Hall Effect sensor to detect tire rotation).
22. Develop a timing system for a 4 lane pinewood derby track.
23. Develop a playing board and control system for your favorite game (Yahtzee, Connect Four,
Battleship, etc.).
24. You have a very enthusiastic dog that loves to chase balls. Develop a system to launch balls for
the dog.

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