======PROJECT======
PROJECT: Colored LED Research (clr1)

=====Objective=====
A mild throwback to the ledX projects, where we find ourselves once again playing with an LED, only an LED of MANY colours: the RGB LED! We will be eliciting additional effects from the RGB LED in this project.

=====Abstraction=====
{{page>haas:fall2020:common:projects:abstraction&noheader}}

=====Locational Awareness=====
{{page>haas:fall2020:common:projects:location&noheader}}

=====Reading=====
In "The C Book", please read through Chapter 8.

Review needed concepts in [[https://www.tutorialspoint.com/cprogramming/|this tutorial]] and also [[https://www.cprogramming.com/tutorial/c-tutorial.html?inl=hp|this one]]

ALSO: read through Chapter 5 in the [[https://lab46.g7n.org/downloads/tutorial.pdf|FreeNove Tutorial]]

AND: the wiringPi API on [[http://wiringpi.com/reference/software-pwm-library/|Sofware PWM functionality]]

=====Background=====
For this project, you will be working with a C program using the wiringPi library on the Raspberry Pi, wiring up a circuit containing an RGB LED to your breadboard and witnessing your ability to access and control it in varying states of on and off (more than just simply "ON" and "OFF") via a software-based Pulse Width Modulation (PWM) scheme.

=====Loops=====
{{page>haas:fall2020:common:projects:loops&noheader}}

=====Input and Output via the GPIO pins on the pi=====
One of the intended uses of the Raspberry Pi and other small, single board computers is as an interface tool to peripherals in projects, personal and industrial.

The pi has a set of **General Purpose Input Output** (GPIO) pins intended for precisely this purpose:

{{ :haas:fall2020:common:projects:gpio-pinout-diagram-2.png |}}

Please note the orientation of the pi (ethernet/USB at bottom) to calibrate yourself to the location of pin 1 and all subsequent pins, along with their identified function (ie top left pin, pin 1, provides a constant 3.3v DC power)

We can also get a live update on the state of each pin on our pi itself, using the '**gpio readall**' command at our pi prompt:

<cli>
yourpi:~/src/desig/clr1$ gpio readall
 +-----+-----+---------+------+---+---Pi 4B--+---+------+---------+-----+-----+
 | BCM | wPi |   Name  | Mode | V | Physical | V | Mode | Name    | wPi | BCM |
 +-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
 |     |     |    3.3v |      |   |  1 || 2  |   |      | 5v      |     |     |
 |   2 |   8 |   SDA.1 | ALT0 | 1 |  3 || 4  |   |      | 5v      |     |     |
 |   3 |   9 |   SCL.1 | ALT0 | 1 |  5 || 6  |   |      | 0v      |     |     |
 |   4 |   7 | GPIO. 7 |   IN | 0 |  7 || 8  | 1 | ALT5 | TxD     | 15  | 14  |
 |     |     |      0v |      |   |  9 || 10 | 1 | ALT5 | RxD     | 16  | 15  |
 |  17 |   0 | GPIO. 0 |   IN | 0 | 11 || 12 | 0 | IN   | GPIO. 1 | 1   | 18  |
 |  27 |   2 | GPIO. 2 |   IN | 0 | 13 || 14 |   |      | 0v      |     |     |
 |  22 |   3 | GPIO. 3 |   IN | 0 | 15 || 16 | 0 | IN   | GPIO. 4 | 4   | 23  |
 |     |     |    3.3v |      |   | 17 || 18 | 0 | IN   | GPIO. 5 | 5   | 24  |
 |  10 |  12 |    MOSI |   IN | 0 | 19 || 20 |   |      | 0v      |     |     |
 |   9 |  13 |    MISO |   IN | 0 | 21 || 22 | 0 | IN   | GPIO. 6 | 6   | 25  |
 |  11 |  14 |    SCLK |   IN | 0 | 23 || 24 | 1 | IN   | CE0     | 10  | 8   |
 |     |     |      0v |      |   | 25 || 26 | 1 | IN   | CE1     | 11  | 7   |
 |   0 |  30 |   SDA.0 |   IN | 1 | 27 || 28 | 1 | IN   | SCL.0   | 31  | 1   |
 |   5 |  21 | GPIO.21 |   IN | 1 | 29 || 30 |   |      | 0v      |     |     |
 |   6 |  22 | GPIO.22 |   IN | 1 | 31 || 32 | 0 | IN   | GPIO.26 | 26  | 12  |
 |  13 |  23 | GPIO.23 |   IN | 0 | 33 || 34 |   |      | 0v      |     |     |
 |  19 |  24 | GPIO.24 |   IN | 0 | 35 || 36 | 0 | IN   | GPIO.27 | 27  | 16  |
 |  26 |  25 | GPIO.25 |   IN | 0 | 37 || 38 | 0 | IN   | GPIO.28 | 28  | 20  |
 |     |     |      0v |      |   | 39 || 40 | 0 | IN   | GPIO.29 | 29  | 21  |
 +-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
 | BCM | wPi |   Name  | Mode | V | Physical | V | Mode | Name    | wPi | BCM |
 +-----+-----+---------+------+---+---Pi 4B--+---+------+---------+-----+-----+
</cli>

Yes, it may be packed with information, but it is an informative, technical reference.

Why is this so layered and directed, you may ask? Well, it is a matter of competing standards (approaches to identification of each pin, based on particular reference points).

For example, the "Physical" columns (dead center) in the center conform to the image diagram I posted above of the 40 pins (where pin 1 is the top-left).

The "BCM" columns (far left and far right) refer to the hardware identifications for each pin by the manufacturer. You might notice that BCM pin 17 (physical pin 11) corresponds to wPi pin 0.

And the "wPi" columns (second from left, and second from right), correspond to the pin identifications as use by the wiringPi library, which we are using here.

Additionally, we see "Mode" and "V" columns; mode informs us of the operating mode of that pin at present configuration (IN means it is configured for INPUT, OUT means it is configured for OUTPUT). V implies voltage on the pin (0 means no voltage, 1 means there is voltage present at time of checking). For this project, we will be configuring a specific pin to OUTPUT mode, and modulating it between a state of ON (1) and OFF (0).

So, in exploring the use of the table: if we wanted to hook a component up to wiringPi pin #0, that corresponds to manufacturer (BCM) pin 17, which is physical pin 11.

You will want to verify placement before supplying power, that is why we are taking things slow, and providing you opportunities to confirm (by posting pictures in the discord channel) before proceeding.

It may seem a bit bewildering or overwhelming at first, but like anything, time and exposure will ensure it becomes increasingly second nature.

====Grabbing project resources (on lab46)====
I have prepared a **grabit** for resources related to this project. To obtain:

<cli>
lab46:~/src/desig$ grabit desig clr1
make: Entering directory '/var/public/SEMESTER/desig/clr1'
'/var/public/SEMESTER/desig/clr1/Makefile' -> '/home/user/src/desig/clr1/Makefile'
'/var/public/SEMESTER/desig/clr1/clr1.c' -> '/home/user/src/desig/clr1/clr1.c'
make: Leaving directory '/var/public/SEMESTER/desig/clr1'
lab46:~/src/desig$ 
</cli>

At which point you can change into the newly created and populated **clr1/** directory.

====Getting project resources from lab46 to your pi====
Okay, you've snagged the project files on lab46. Now, how to get them to your pi?

The same way you've been juggling project files already, by using your mercurial repository!

Using the **hg** tool, be sure to **add**, **commit**, and **push** successfully on lab46.

Then, over on your pi, use **hg** to **pull** and **update** the new changes into place. Then you can proceed.

=====Wiring up our circuit=====
Please reference the [[https://lab46.g7n.org/downloads/tutorial.pdf|FreeNove Tutorial]], Chapter 5, Project 5.1 for the parts and circuit diagram. 

The circuit for this project remains identical to that of clr0.

=====Program=====
It is your task to obtain, study, and complete a program (clr1.c) that is to explore and display the gradual changing of color components, in isolation and combinations. You must complete the parts as indicated in the comments to the actions described.

=====Compiling=====
Since the grabit brought in a Makefile, you can compile your code simply by typing: **make**

Any compiler errors will go into a text file called **errors**

To do a full cleaning, run: **make clean** then **make** (or **make debug**)

If you'd like to see compiler messages as you compile, run: **make debug**

When done and ready to submit, on lab46: **make submit**

=====Submission=====
To successfully complete this project, the following criteria must be met:

  * Code must compile cleanly (no notes, warnings, nor errors)
  * Output must be correct, and match the form given in the sample output above.
  * Code must be nicely and consistently indented
  * Code must be well commented
  * Do NOT double space your code. Group like statements together.
  * Output Formatting (including spacing) of program must conform to the provided output (see above).
  * Track/version the source code in a repository
  * Submit a copy of your source code to me using the **submit** tool.
  * Post required images and obtain needed confirmation to proceed from me on class channel on discord.

To submit this program to me using the **submit** tool, run the following command at your lab46 prompt:

<cli>
lab46:~/src/desig/clr1$ submit desig clr1 clr1.c
Submitting desig project "clr1":
    -> clr1.c(OK)

SUCCESSFULLY SUBMITTED
</cli>

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.

What I'll be looking for:

<code>
91:clr1:final tally of results (91/91)
*:clr1:post picture of program-powered LED in layout to #desig [13/13] 
*:clr1:grabit on the code on lab46 by Sunday before deadline [13/13]
*:clr1:clr1.c code adequately modified per project requirements [26/26]
*:clr1:colors are appropriately reset prior to each section [13/13]
*:clr1:color levels adjust in offsets of 10, with useful delays [13/13]
*:clr1:updated code is pushed to lab46 repository [13/13]
</code>

Additionally:
  * Solutions not abiding by spirit of project will be subject to a 25% 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 will be subject to a 25% overall deduction
  * Solutions not organized and easy to read are subject to a 25% overall deduction