ENGR 101 Engineering Technology

Assignment 2 Due date: Friday, 12 April, 2019 (15:00 hrs)

The assignment is an individual assessment worth 5% of the final course work. The assignment must be typed using a wordprocessor (eg MS Word). You must include all the calculations for each answer that you provide.

Question 1

In a microcomputer, the address of memory locations are binary numbers that identify each memory circuit where a byte is stored. The number of bits that make up an address depends on how many available memory locations. Since the number of bits can be very large, the addresses are often specified in hexadecimal instead of binary.

a) If a microcomputer uses a 20-bit address, how many different memory locations are there?

b) How many hexadecimal digits are needed to represent the address of a memory location?

c) What is the hexadecimal address of the 256th memory location? (The first address is always 0)

d) The computer program is stored in the lowest 2 kilobyte block of memory. What is the starting and ending addresses of this block?

Question 2

In an audio CD, the audio voltage is typically sampled about 44,000 times per second, and the value of each sample is recorded on the CD surface as a binary number. In other words, each recorded binary number represents a single voltage point on the audio signal waveform.

a) If the binary numbers are six bits in length, how many different voltage values can be represented by a single binary number? How many values for eight bits and ten bits?

b) If ten-bit numbers are used, how many bits will be recorded on the CD in 1 second?

c) If a CD can typically store 5 billion bits, how many seconds of audio can be recorded when ten-bit numbers are used?

Question 3

The trunk of an automobile is opened in one of two ways by pressing a button on the trunk lid or by pressing the trunk button on the key fob. However, these buttons only open the trunk under certain conditions for safety and security purposes. The logic diagram for this circuit is shown below:

The output for the circuit is Truck_unlock.

HIGH activates the latch release and opens the trunk.

The inputs are defined as follows:

a) Write the conditions in English that will open the trunk.

b) Write the Boolean expression using the signal names given.

c) Minimize the Boolean expression that you have written in part b) above using

i. the Boolean algebra

ii. Karnaugh Map.

Question 4

A jet aircraft employs a system for monitoring the speed (revolutions per minute, rpm), pressure and temperature values of its engines using sensors that operate as follows:

RPM sensor output

= 0 only when speed < 4800 rpm

P sensor output

= 0 only when pressure < 220 psi

T sensor output

= 0 only when temperature < 200 oF

The figure shown below shows the logic circuit that controls a cockpit warning light for certain combinations of engine conditions. Assume that a HIGH at output W activates the warning light.

a) What are the engine conditions that will give a warning to the pilot?

b) Write the Boolean expression using the signal names given.

c) Draw a circuit that will produce the same output using NAND gates only.

Question 5

Shown below is the intersection of a main highway with a secondary access road. Vehicle-detection sensors are placed along the lanes C and D (on the main highway) and lanes A and B (on the access road). These sensors outputs are LOW when no vehicle is present and HIGH when a vehicle is present.

The intersection traffic light is to be controlled according to the following logic:

1. The East-West (E-W) traffic light will be green whenever both lanes C and D are occupied.

2. The E-W light will be green whenever either C or D is occupied but lanes A and B are not both occupied.

3. The North-South (N-S) light will be green whenever both lanes A and B are occupied but C and D are not both occupied.

4. The N-S light will also be green when either A or B is occupied while C and D are both vacant.

5. The E-W light will be green when no vehicles are present.

Using the sensor signals (A, B, C, and D) as inputs, design a logic circuit to control the traffic light.

There should be two outputs (N-S and E-W) that go HIGH when the corresponding light is to be green.

Simplify the circuit as much as possible and show all your steps.