CORK INSTITUTE OF TECHNOLOGY
INSTITIÚID TEICNEOLAÍOCHTA CHORCAÍ
Autumn Examinations 2008/09
Module Code: ELTR 7019
External Examiner(s):
School: Electrical and Electronic Engineering
Programme Title: B.Eng. in Electronic Engineering - Award
Programme Code: EELXE_7_Y3
Mr. D. Deneiffe
Internal Examiner(s):
Instructions:
Mr. F. O’Reilly
Answer 3 Questions. All questions carry equal marks.
Duration: 2
Sitting: Autumn 2009
Requirements for this examination:
Note to Candidates: Please check the Programme Title and the Module Title to ensure that you have received the correct examination paper.
If in doubt please contact an Invigilator.

1. (a) Compare and contrast microprocessors and micro-controllers. What advantages,
(b) The following is a set of embedded electronics applications. o Video Cassette Recorder(VCR) Internal Control Unit o Automobile On-Board Computer controlling Ignition, traction and ABS o General Purpose home computer
For the each of the applications listed identify,
(i) Approximate number of Input & Outputs
(ii) Estimate of speed/performance required.
(iii) Complexity/Range of algorithms/programmes to execute.
(9 marks)
From the following micro-controller/microprocessors choices suggest and justify suitable models for each of the above applications. Motorola 68000 microprocessor, Intel Pentium 3 family, Microchip PIC, Motorola 68332 Micro-
(c) The PIC 16c74 arranges its memory into two register banks. What
[15 marks] advantages/disadvantages does this have? How do you control which register bank is addressed/selected at any time? [10 marks]
[Total: 34 marks]

2. (a) Interrupt handling is important for embedded systems. Explain what happens when an interrupt occurs in the PIC and how the interrupt should be handled.
Explain what memory addresses are used, the different types of interrupts available and how they can be differentiated. [10 marks ]
(b) Derive and explain the following formula based on the Clock Speed and Time, which can be used to calculate the pre-load values for Timer1 of the PIC Microcontroller. How can this be changed to suit Timer2?
Pre-load Value = 10000
(hex)
(Using Internal Clock)
- Time * FOSC
Prescalar * 4
[12 marks]
Calculate the pre-load value for the 16c74 micro-controller to generate a 2.0 kHz square wave using Timer 1 or Timer2, specifying which timer it is for and showing in code how the value would be loaded in. Assume a clock of 4MHz.
[10 marks]
[Total: 34 marks]
3. (a) Describe the capabilities and operation of the Analog to Digital Converter Unit of the Microchip PIC, explaining.
The possible input signal levels.
The number of possible inputs
The possible output values.
Key registers used both in the configuration.
Key registers during the operation.
How does one know a conversion has completed? [14 marks]
(b) Write the configuration, interrupt handling and data reading sections of a PIC assembly language program for the 16c74 micro-controller, which continually reads in an analogue voltage from 0 -> 5V on RA0 and outputs it in binary
[Total: 34 marks]

4. (a) What peripheral device is used on the PIC to achieve a Serial Data interface?
How would this be configured to give an asynchronous serial interface at 7200 baud? Calculate the baud rate generator configuration value and show how it
Explain using a diagram how it operates to
Transmit data serially or
Receive data serially
Examine only one case above only, explaining the registers and pins used.
[8 marks]
(b) Describe how a LCD Display unit can be connected to a micro-processor/microcontroller and used to display text. Describe the input signals necessary for the
LCD unit and how a micro-processor can supply these. Provide sample code to show how the LCD control can be done, paying particular attention to the slowness unit.
[Total: 34 marks]