Reference no: EM132413527

4CCS1CS1 - Computer Systems - Kings College London

Base Task: Simple Morse Code

For the program that you will turn in, you will use the circuit that you made in lab 4 to broadcast a short message via Morse code on the LEDs.

What is Morse code? Morse code is a method of transmitting text information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment.

Your base program will blink a 3 letter sequence in Morse code on the LEDs. You three letter sequence is the first three letters of your first name.

• For expample, Charles Babbage's code would be CHA.

If your first name is less than three characters, you should use the first 3 characters of your first name concatenated with your surname.
So that we can perceive the Morse code, we will use a unit length of 200 milliseconds (ms). This means the duration of a dot is 200 ms, and a dash is 600 ms.

Make sure that:
1. Your program is called morse.s.
2. Your program writes the Morse code sequence to the PB0 pin of PORTB. This is the same set-up as in the other programs you wrote in Lab 4.
3. Your program will continually loop through the 3-letter sequence.
4. Assume that there is no word break after your 3 letters, just repeat the 3-letter sequence.

For example, if your sequence was ABC, then your program would run as follows: 1.Turn ON the LED for 200 ms for the first dot of the letter A
2. Turn OFF the LED for 200 ms for the inter-part space of the letter A
3. Turn ON the LED for 600 ms for the first dash of the letter A
4. Turn OFF the LED for 600 ms for the inter-letter space between the letters A and B
5. Turn ON the LED for 600 ms for the first dash of the letter B
6. and so forth
7. Until the last dot of letter C
8. Turn OFF the LED for 600 ms for the final inter-letter space.
9. Loop back to the beginning of the Morse code sequence

Challenge Task: Odd, Even, modulo 5
Extend your morse.s program as follows.
• The morse code sequence should loop 50 times (1-50).
• On odd iterations (1, 3, 5, , 49) your three characters should be displayed in their normal order.
- e.g. ABC
• On even iterations (2, 4, 6, , 50) your three characters should be displayed in reverse order.
- e.g. CBA
Using comments, you should explain how you have implemented the check of whether the iteration is even or odd. Once you have this behaviour working, you should again extend your program as follows.
On iterations that are divisible by 5 (5, 10, 15, , 50) your program should display a '5' after what would normally
be displayed on that iteration.
- e.g. ABC5 or CBA5

Just for fun: LED blinking
Only attempt this challenge if you have completed the previous tasks. This section is worth no marks, but it is your chance to practice and show off your skills!
Once the morse code sequence has terminated, your LEDs should display a repeating pattern.
It is up to you to create a pattern for the LEDs. The more technically impressive the pattern the better!
For example, you could implement a ping-pong like pattern, where only a single LED is on at a time, and it appears to move back and forth across the LEDS.
• 1000 → 0100 → 0010 → 0001 → 0010 → 0100 → 1000 → ...
You should not submit your work for this task.

Attachment:- Computer Systems.rar