Table of Contents

Corning Community College

ENGR1050 C for Engineers

PROJECT: Seeing The Light (STL2)

OBJECTIVE

Time to explore optimizing our logic further, through the use of a loop and demonstrating the effectiveness of our logic by scaling up the number of LEDs in our counter (to at least 8).

PROCESS

Do note, the productive way to go about this project involves taking the following steps:

If you start too late, and do not ask questions, and do not have enough time and don't know what is going on, you are not doing the project correctly.

TASK

After exploring, assembling, and testing the intended circuit (8+ LEDs), adapt the provided C code to use the bank of connected LEDs to count in binary from 00000000 to at least 11111111 (0 to 255).

Using the current value of count, your task is to make use of ONE if statement and copious use of bitwise logic to determine from an ongoing count the state of the individual bits.

It is your task to write a C program that interfaces successfully with the eight or more independently connected LED circuits, arranged in some orientation to ascertain an order or positioning, where your program will (in endless fashion, or until being manually interrupted) display a count (in binary) of values from 0 to at least 255 (then rollover, or reset).

If “1” means the LED in that position is ON, and “0” means the LED in that position is OFF, then you want to write a program that performs the following progression (over and over again): 

0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1
0 0 0 0 0 0 1 0
0 0 0 0 0 0 1 1
0 0 0 0 0 1 0 0
0 0 0 0 0 1 0 1
0 0 0 0 0 1 1 0
0 0 0 0 0 1 1 1
0 0 0 0 1 0 0 0
. . .
1 1 1 1 1 0 0 1
1 1 1 1 1 0 1 0
1 1 1 1 1 0 1 1
1 1 1 1 1 1 0 0
1 1 1 1 1 1 0 1
1 1 1 1 1 1 1 0
1 1 1 1 1 1 1 1   <-- 255, the maximum value to display when there are 8 bits/LEDs
0 0 0 0 0 0 0 0   <-- 0, we "roll over" and start again
0 0 0 0 0 0 0 1
0 0 0 0 0 0 1 0
. . .

GRABIT

To assist with consistency across all implementations, data files for use with this project are available on lab46 via the grabit tool. Be sure to obtain it and ensure your implementation properly works with the provided data. 

lab46:~/src/SEMESTER/DESIG$ grabit DESIG PROJECT

Components and wiring

An example of one way to wire up the LED bar:

EDIT

You will want to go here to edit and fill in the various sections of the document:

STL2

loops

A “for” loop is a top driven loop that will test the condition of a statement before the loop begins to see if it is true. It is a control flow statement that is less “messy” than other types, as while it needs more conditions in order to run, it needs less input code in order to run. An example of a “for” loop is as follows:

for (index=0;index<10;index=index+1) { 

fprintf (stdout,"%\n", index);

}

The looping variable is “index”, the loop starts when index=0, will continue to loop as the index increases by a value of 1 for each loop, and will stop/end when index=10, with the value stored in “index”.

for loop

A type of control flow statement that allows you to execute a desired task a specified number of times. The general form we see is as follows:

if(initialization; condition; update) 

{task we wish to execute}

Initialization: Typically used to initialize a loop control variable (we used “index” in class). Condition: This part is evaluated at the start of each successive loop. If the condition is “true,” the loop is run and the code is executed. If the condition is “not true,” then the loop is terminated. Update: Executed after each iteration, this term is used to update the loop control variable>

while loop

A type of control flow statement that will continue to run whatever code is written in the body as long as the predetermined condition is met. For example, in this class, we see the while loops with the condition (1) which simply means “true.” This means that as long as the condition is true (1) the loop will continue to run until it is interrupted by the user. The format we see in this class is

while (1)

{task we wish to repeat here}

do-while loop

bitwise operations

bitwise AND

A bitwise AND is one of the multiple different bitwise functions that can be used not only to strengthen code but also to shorten code and make the code more succinct and more efficient. A bitwise AND is represented by the “&” symbol. A bitwise AND compares the two different values that it is given in order to create an answer. The bitwise AND compares the values to see which portions of each value are matching, because a bitwise AND will only output a 1 (AKA a success) if the two values are the same. For example if you were to bitwise AND the values 1010 and 0010, the response created would be 0010 because the second place of both of the values was the only place where both values had a 1. bitwise AND's are extremely useful for stl2 in order to allow for easier comparison between the current counter (or number) value that the program is on as well as the place calculator known as mask. The comparison of number and mask allows for our code to more easily tell what place we are currently in and whether that place needs to be on or off.

logical left shift

A bitwise operation that moves all bits in an operand to the left by a specific number of positions. What does this mean? In C, we use « to represent a left shift of one place. We could also do «# to left shift that specific number of places. In practice, this would shift the ones place to the twos place, the twos place to the fours place, the fours place to the eights place, and so on so fourth. In the context of this project, when used in a loop, this operation would allow us to perform sequential operations on a specific value of multiple bits by successively shifting the value one place to the left with each loop.

 

STRATEGY

The general flow of the process (one way of going about it, anyway) can be described as follows: 

SET COUNTER TO ZERO
REPEAT INFINITELY:
    SET PLACE TO ONE
    REPEAT UNTIL PLACE IS GREATER THAN EIGHT:
        SHOULD THE PLACE POSITION HAVE A ONE:
            ACTIVATE THE PLACE’S LED
        OTHERWISE:
            DEACTIVATE THE PLACE’S LED

        LET PLACE BECOME THE NEXT PLACE POSITION
    KEEP GOING

    PAUSE FOR HUMAN PERCEPTION
    LET THE COUNTER BE INCREMENTED BY ONE
KEEP GOING

SUBMISSION

To be successful in this project, the following criteria (or their equivalent) must be met:

Submit Tool Usage

Let's say you have completed work on the project, and are ready to submit, you would do the following (assuming you have a program called uom0.c): 

lab46:~/src/SEMESTER/DESIG/PROJECT$ make submit

You should get some sort of confirmation indicating successful submission if all went according to plan. If not, check for typos and or locational mismatches.

RUBRIC

I'll be evaluating the project based on the following criteria: 

91:stl2:final tally of results (91/91)
*:stl2:used grabit to obtain project by the Sunday prior to duedate [13/13]
*:stl2:clean compile, no compiler messages [13/13]
*:stl2:program conforms to project specifications [13/13]
*:stl2:uses at least eight LEDs for the binary counter [13/13]
*:stl2:program uses only one selection structure in loop to do task [26/26]
*:stl2:code tracked in lab46 semester repo [13/13]

Pertaining to the collaborative authoring of project documentation

Additionally