NAND/NOR Logic Gate Replacement Training tool Team 34: Jeremy Diamond and Matthew LaGreca Just introduce ourselves here and the title of our project

Objective: Easy practice of NAND/NOR equivalents Important introductory topic of ECE Begin learning at the high school level NAND/NOR is more efficient than AND/OR/NOT “For those interested in Electrical and Computer Engineering, one of the first things that you learn is making of circuits with logic gates. For ______ and I, we started learning about logic gate circuitry in high school, but learning about electronics can start at any age. One thing that we are taught in ECE at UIUC is that only using NAND or NOR chips to make a circuit is more efficient and a standard of industry due to NAND and NOR chips being more power efficient by using less transistors than AND OR and NOT chips. However, learning the NAND/NOR equivalency of AND/OR/NOT circuit can be a tricky skill to develop when it is first introduced.”

Learning tool for those new to circuits Build AND/OR/NOT circuit Build NAND/NOR equivalent Displays let user know equivalence of both “So we saw a need to create a visual aid for those who are first learning about logic gates. How our learning tool works is that you first build a circuit using the AND/OR/NOT gates that we give you, and then you try to build the logical equivalent using either NAND gates or NOR gates. If you did so successfully, you will see an LED light up telling you that the two circuits that you made are logically equivalent”

Full Block Diagram “As such, our project has 3 main modules to it: Power, Circuit Design, and Circuit Comparison and Truth Table Display.”

Power Module “The Power Module only serves one purpose: to provide the appropriate voltage levels to the rest of the modules. Using a wall power supply and some voltage regulators, we accomplish just that by stepping down a supplied voltage of 5.9V to 3.3V for the majority of the circuit and 5V for the Logic Comparator Circuit.”

Power Module Requirements Takes in power from wall outlet Step-down circuits to supply correct voltages “And as you can see, the requirements needed of the Power Module reflect just that. (add a few more notes here, or maybe restructure some of the other slides), however the manipulation of the input voltages to the other two modules is really the secret to how our project works”

Circuit Design Module “And as such, the Circuit Design Module takes in 3.3V as input for both the switches and the Design Board in order to provide functionality to the visual aid aspect of our project. But before getting to that, let’s introduce how the visual aid works with the designing of each circuit. The switches function as to toggle between NAND or NOR mode for the NAND/NOR side, and the circuit design between 2 input and 3 input”

Requirements Position passes correct voltage to microcontroller based Toggling switches change truth table calculation “It’s important that this module sends the correct voltage levels when each gate is plugged in, otherwise the truth tables won’t calculate properly when each voltage level is sent to the microcontrollers. Similarly, toggling the switches needs to appropriately send the correct voltage high or low to the microcontroller, or else the calculated truth table won’t be accurate to how the user has set the input toggle and the NAND/NOR toggle”

Logic Gate Placement “As soon as the user plugs in learning tool, they are ready to get started with building each circuit. For the AND/OR/NOT side of the board, you have 2 places that you can place an AND or an OR gate and 3 places where you can place a NOT gate or a through wire. Similarly, for the NAND/NOR side of the board you have 2 spots where you can place a NAND or a NOR gate, and then 5 spots where you can place a through wire or a NAND/NOR gate that will basically function as a NOT gate”

Physical Board Design “However, our logic gate pieces that we provide aren’t actually logic gates, but rather just collections of banana plugs that when inserted send either 3.3V or GND to Circuit Comparison and Truth Table Display module to use when calculating truth tables. Each chip has a unique arrangement of banana plugs, so that they can only be inserted in specific positions on the Design Board. We specifically did this as to make the use of this board easier, so that the user can’t place AND/OR/NOT gates on the NAND/NOR side and vice versa.”

Circuit Comparison and Truth Table Display Module “After the all the gates and switches have been set, the Circuit Comparison and Truth Table Display Module takes care of the rest of the functionality of the learning tool, abstracted away from the user”

Microcontroller Code Truth table determined by inputs (Circuit Design Module) NAND/NOR forced to 0s by Wrong Chips Wrong chips determined by 2-bit gate identifiers “Based on the voltages set by the user’s chip placements, the Microcontroller takes in those values as inputs and is able to calculate the truth table based on looking at the inputs and outputting a truth table corresponding to said inputs. The microcontrollers for truth table calculation just cycle through a bunch of if else statements and output a truth table depending on which condition is met. Similarly, if a NAND chip was used during NOR mode, or if a NOR was used during NAND mode, the NAND/NOR truth table is forced to display all zeros, indicating to the user that they used a NAND/NOR improperly. Normally with the truth table calculation, a 1 will represent the presence of a certain gate (either AND, NOT or NAND/NOR), and a 0 will represent an absence (through wire, or an OR). However, the NAND/NOR chips send an extra bit as to be able to differentiate them better when calculating the Wrong Chips used signal, 11 being NAND 10 being nor, and 00 being through.”

Microcontroller PCB Microcontrollers take inputs from each position Outputs correct truth table Indicates if wrong chip used for NAND/NOR “The outputs from the Circuit Design Module are then wired as inputs to this PCB so that the outputs are linked up to LEDs either telling the truth tables of the designed circuits to the user, or to denote to the user whether they used a NAND or a NOR chip wrongly”

Logic Comparator Circuit “In addition to wiring the outputs of the Circuit Design Module to the previous PCB, the truth tables being output from the appropriate microcontroller are wired into this PCB, which contains the the Logic Comparator Circuit. If the two truth tables are equivalent, then the LED denoting the two circuits being logically equivalent will light up”

“This is the underside to the learning tool with all the wirings connected, and as you can see it is rather messy. If we were to continue with this project, we would better encapsulate this so that the user cannot see or interact with anything on this backside.”

Requirements NAND/NOR gate misused -> Wrong Chip LED on Output truth tables based on gate positions “Lastly, the requirements for this module are that the misuse of a NAND during NOR mode triggers the Wrong Chip signal on, and similarly for when a NOR is used during NAND mode. Not only that, but most importantly the truth tables need to be calculated correctly based on what gates were used where in each circuit.”

Example AND Circuit and Equivalent NAND Circuit

Truth Table and Wrong Chip Display NAND Mode NOR Mode

*Bring to our High Schools for students to use* Future Work Combine both PCBs into one board Reduce number of banana sockets and plugs With enhanced components, minimize overall board size Replace current switches with SPST equivalent *Bring to our High Schools for students to use*

Questions?