Table of Contents
Corning Community College
ENGR1050 C for Engineers
PROJECT: Seeing The Light (STL1)
OBJECTIVE
We continue our explorations of the electronics kit, by adding additional LEDs to control them in unison with a C program on our pi, having them count in binary.
PROCESS
Do note, the productive way to go about this project involves taking the following steps:
- starting early
- reading the project page
- asking questions regarding things you do not know, are not clear on, or are confused about
- as information, concepts, processes become clear, that is something you can contribute to the project documentation (so you can better remember)
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 (4 LEDs), adapt the provided C code to use the bank of connected LEDs to count in binary from 0000 to 1111 (0 to 15).
Using the current value of count, your task is to make use of if statements and 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 four 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 15 (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 1 0 0 1 0 0 0 1 1 0 1 0 0 0 1 0 1 0 1 1 0 0 1 1 1 1 0 0 0 1 0 0 1 1 0 1 0 1 0 1 1 1 1 0 0 1 1 0 1 1 1 1 0 1 1 1 1 <-- 15, the maximum value to display 0 0 0 0 <-- 0, we "roll over" and start again 0 0 0 1 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
EDIT
You will want to go here to edit and fill in the various sections of the document:
STL1
REVIEW OF BITWISE LOGIC
Relational Operators: - “==” is equal to - “!=” is not equal to - “<” is less than - “>” is greater than - “⇐” less than or equal to - “>=” greater than or equal to
BITWISE AND
The output of bitwise AND is 1 if the corresponding bits of the two operands is 1. If either bit of an operand is 0, the result is 0. In C, the bitwise AND operator is denoted by “&”.
USING BINARY
To show that a number is in binary, use 0b before it. For example: 0b0000 would represent 0 in binary and 0b1111 would be equivalent to 15 in the decimal system. Otherwise, 1111 may be confused for 1,111 in decimal. This project can be done in decimal, but it may make it easier to use decimal, because 0b0010 definitely requires the twos place LED to light up, since the LEDs are counting in binary.
LIGHT PATTERN
(0000) = (4th, 3rd, 2nd, 1st) 0 0 0 0 (0) - ZERO LIGHTS ON 0 0 0 1 (1) - 1ST LIGHT ON 0 0 1 0 (2) - 2nd LIGHT ON 0 0 1 1 (3) - 1st AND 2nd LIGHTS ON 0 1 0 0 (4) - 3rd LIGHT ON 0 1 0 1 (5) - 3rd AND 1st LIGHTS ON 0 1 1 0 (6) - 3rd and 2nd LIGHTS ON 0 1 1 1 (7) - 3rd, 2nd and 1st LIGHTS ON 1 0 0 0 (8) - 4th LIGHT ON 1 0 0 1 (9) - 4th and 1st LIGHTS ON 1 0 1 0 (10)- 4th and 2nd LIGHTS ON 1 0 1 1 (11)- 4th, 2nd and 1st LIGHTS ON 1 1 0 0 (12)- 4th and 3rd LIGHTS ON 1 1 0 1 (13)- 4th,3rd and 1st LIGHTS ON 1 1 1 0 (14)- 4th,3rd and 2nd LIGHTS ON 1 1 1 1 (15)- 4th,3rd,2nd and 1st LIGHTS ON 0 0 0 0 0 0 0 1 0 0 1 0
BITWISE INCLUSIVE OR
The bitwise inclusive OR, is represented in C with a vertical bar symbol (often referred to as a pipe): |
This operator compares the values of some operands in binary and yields a string of bits that contains all the bits of each operand (OR operation).
Example: 01100011 | 00011001 yields 01111011
Similarly, you can perform this operation in any base, including decimal: 10 | 4 is equal to 7 because
00001010 | 00000100 == 00001110
BITWISE EXCLUSIVE OR
Exclusive OR, typically referred to as XOR, is denoted by the ^ operator in C.
XOR compares some operands in binary, and for each bit compared yields 1 if and only if the bits of each operand have one and only one 1 between them.
Example:
1011 ^ 1101 == 0110
This of course can be done with integers of any base, like so:
3 ^ 7 == 4
Which would be interpreted in binary as:
0011 ^ 0111 == 0100
XOR is an important operation that, when combined with AND, can do operations such as binary addition.
BITWISE NOT
The bitwise NOT operation, represented with the operator ~, can be thought of simply as an inverter. That is, it takes some operand and inverts each bit.
Example:
~0011 == 1100
This can be done for different bases as well:
~5 == 10
Because 5 is represented in binary as 0101, inverting the bits results in binary 1010, i.e. decimal 10.
SELECTION STRUCTURES: IF
For this project, we will mainly be using the if and else functions. An IF statement tells the computer that when the condition specified by the statement is met, then to do the command string later specified. When the condition specified by the statement is not met, it will completely skip the function and continue on its journey to make you frustrated. BUT, we can add an else command to tell the computer to do a task or command string when the condition isn't met.
For example, here is the outline of the IF statement we should be using:
if (statement) {
do this;
}
else {
do this instead;
}
Where statement is the statement you want to test as true or false, and both do this and do this instead are other functions, commands, or whatnot. When the statement is true, it will run the do this line. But when the statement is false, it will run the do this instead line.
STRATEGY
The general flow of the process (one way of going about it, anyway) can be described as follows:
SET COUNTER TO ZERO
REPEAT:
SHOULD THE ONE'S POSITION HAVE A ONE:
ACTIVATE THE ONE'S PLACE
OTHERWISE:
DEACTIVATE THE ONE'S PLACE
SHOULD THE TWO'S POSITION HAVE A ONE:
ACTIVATE THE TWO'S PLACE
OTHERWISE:
DEACTIVATE THE TWO'S PLACE
SHOULD THE FOUR'S POSITION HAVE A ONE:
ACTIVATE THE FOUR'S PLACE
OTHERWISE:
DEACTIVATE THE FOUR'S PLACE
SHOULD THE EIGHT'S POSITION HAVE A ONE:
ACTIVATE THE EIGHT'S PLACE
OTHERWISE:
DEACTIVATE THE EIGHT'S PLACE
PAUSE FOR HUMAN PERCEPTION
LET THE COUNTER BE INCREMENTED BY ONE
SUBMISSION
To be successful in this project, the following criteria (or their equivalent) must be met:
- Project must be submit on time, by the deadline.
- Late submissions will lose 33% credit per day, with the submission window closing on the 3rd day following the deadline.
- All code must compile cleanly (no warnings or errors)
- Compile with the -Wall and –std=gnu18 compiler flags
- all requested functionality must conform to stated requirements (either on this document or in a comment banner in source code files themselves).
- Executed programs must display in a manner similar to provided output
- output formatted, where applicable, must match that of project requirements
- Processing must be correct based on input given and output requested
- Output, if applicable, must be correct based on values input
- Code must be nicely and consistently indented
- Code must be consistently written, to strive for readability from having a consistent style throughout
- Code must be commented
- Any “to be implemented” comments MUST be removed
- these “to be implemented” comments, if still present at evaluation time, will result in points being deducted.
- Sufficient comments explaining the point of provided logic MUST be present
- No global variables (without instructor approval), no goto statements, no calling of main()!
- Track/version the source code in your lab46 semester repository
- Submit a copy of your source code to me using the submit tool (make submit on lab46 will do this) by the deadline.
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:
39:stl1:final tally of results (39/39) *:stl1:used grabit to obtain project by the Sunday prior to duedate [6/6] *:stl1:clean compile, no compiler messages [7/7] *:stl1:program conforms to project specifications [20/20] *:stl1:code tracked in lab46 semester repo [6/6]
Pertaining to the collaborative authoring of project documentation
- each class member is to participate in the contribution of relevant information and formatting of the documentation
- minimal member contributions consist of:
- near the class average edits (a value of at least four productive edits)
- near the average class content change average (a value of at least 256 bytes (absolute value of data content change))
- near the class content contribution average (a value of at least 1kiB)
- no adding in one commit then later removing in its entirety for the sake of satisfying edit requirements
- adding and formatting data in an organized fashion, aiming to create an informative and readable document that anyone in the class can reference
- content contributions will be factored into a documentation coefficient, a value multiplied against your actual project submission to influence the end result:
- no contributions, co-efficient is 0.50
- less than minimum contributions is 0.75
- met minimum contribution threshold is 1.00
Additionally
- Solutions not abiding by spirit of project will be subject to a 50% overall deduction
- Solutions not utilizing descriptive why and how comments will be subject to a 25% overall deduction
- Solutions not utilizing indentation to promote scope and clarity or otherwise maintaining consistency in code style and presentation will be subject to a 25% overall deduction
- Solutions not organized and easy to read (assume a terminal at least 90 characters wide, 40 characters tall) are subject to a 25% overall deduction