Differences

This shows you the differences between two versions of the page.

--- haas:fall2020:common:projects:led1 [2020/09/03 16:49] – [Objective] wedge
+++ haas:fall2020:common:projects:led1 [2021/09/05 09:58] – [On your pi] wedge
@@ Line 106: / Line 106: @@
 {{ :haas:fall2020:common:projects:breadboardlogic.png?400 |}}
+Here's a good video overview of the functionality of a breadboard:
+  * https://www.youtube.com/watch?v=6WReFkfrUIk
 ====(1) T-cobbler and data cable====
 In your kit should be a T-shaped device (known as the "T-cobbler" with some aspect of pin names silkscreened on it, and a 40-pin ribbon cable). Colors may vary, but essentially it looks like this:
@@ Line 144: / Line 148: @@
 Take note of how everything is being plugged in, and what connection on the T-cobbler is being utilized.
-Notice how the circuit runs from ground to resistor to LED to pin "GPIO17/Physical pin 11/Wiring Pi pin 0"
+Notice how the circuit runs from ground to LED to resistor to pin "GPIO17/Physical pin 11/Wiring Pi pin 0"
 Please keep in mind:
@@ Line 199: / Line 203: @@
 With an expanded set of LED circuits, be sure to test the operation of each one.
 =====Program=====
-It is your task to compile, run, expand upon, and understand a program to interface with a set of LEDs (light emitting diodes), a nice software-hardware connection, on your raspberry pi.
+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):
+<code>
+0 0 0
+0 0 1
+0 1 0
+0 1 1
+1 0 0
+1 0 1
+1 1 0
+1 1 1
+0 0 0
+0 0 1
+0 1 0
+0 1 1
+1 0 0
+1 0 1
+1 1 0
+1 1 1   <-- 15, the maximum value to display
+0 0 0   <-- 0, we "roll over" and start again
+0 0 1
+0 1 0
+...
+</code>
+The program files provided for this project are, while not complete, a good base to start from. Be sure to ASK QUESTIONS, and do so EARLY enough so that you aren't in a mad dash to make the deadline.
+=====Bitwise logic=====
+Since the off/on state of each LED is essentially binary in nature (or one bit of an overall sequence), why not utilize the powerful bitwise tools available to us in C?
+====bitwise-AND====
+C provides a bitwise AND operator, the **<nowiki>&</nowiki>** symbol, which can be used in equations to perform bitwise-AND operations:
+<code c>
+char value  = 5;         // 00000101 in binary
+value       = value & 6; //   00000101
+                         // & 00000110
+                         //   ========
+                         //   00000100
+</code>
+Remember the truth table for the AND:
+<code>
+( AND )
+A B | X
+====+===
+F F | F
+F T | F
+T F | F
+T T | T
+</code>
+Think of how this property could be used in combination with other concepts we've learned about in C to solve the problem at hand.
+====bitwise-iOR====
+C provides a bitwise inclusive OR operator, the **<nowiki>|</nowiki>** symbol, which can be used in equations to perform bitwise-iOR operations:
+<code c>
+char value  = 5;         // 00000101 in binary
+value       = value | 6; //   00000101
+                         // & 00000110
+                         //   ========
+                         //   00000111
+</code>
+Remember the truth table for the iOR:
+<code>
+( iOR )
+A B | X
+====+===
+F F | F
+F T | T
+T F | T
+T T | T
+</code>
+Think of how this property could be used in combination with other concepts we've learned about in C to solve the problem at hand.
+====bitwise-xOR====
+C provides a bitwise exclusive OR operator, the **<nowiki>^</nowiki>** symbol, which can be used in equations to perform bitwise-xOR operations:
+<code c>
+char value  = 5;         // 00000101 in binary
+value       = value ^ 6; //   00000101
+                         // & 00000110
+                         //   ========
+                         //   00000011
+</code>
-The program files provided for this project are, while not complete, minimally functional. You merely have to get it on your pi, compile it, and run it, and expand it with the appropriate circuitry hooked up to the specified places. You will want to make sure you UNDERSTAND what is going on. So be sure to ASK QUESTIONS, and do so EARLY enough so that you aren't in a mad dash to make the deadline.
+Remember the truth table for the xOR:
-In future projects you will start implementing more logic to attain further functionality.
+<code>
+( xOR )
+A B | X
+====+===
+F F | F
+F T | T
+T F | T
+T T | F
+</code>
+Think of how this property could be used in combination with other concepts we've learned about in C to solve the problem at hand.
 ====Grabbing project resources (on lab46)====
 I have prepared a **grabit** for resources related to this project. To obtain:
@@ Line 229: / Line 333: @@
 ====On your pi====
-Study and run this program on your pi in conjunction with testing and verifying operation of your properly hooked up electronics circuit. When done, submit it on lab46.
+Implement the needed program on your pi in conjunction with testing and verifying operation of your properly hooked-up electronics circuit. When done, submit it on lab46.
 To utilize the needed functionality for this project, you will need to ensure you have the following packages installed: