A full adder is a digital circuit that performs addition. Full adders are implemented with logic gates in hardware. A full adder adds three one-bit binary numbers, two operands and a carry bit. The adder outputs two numbers, a sum and a carry. The term is contrasted with a half adder, which adds two binary digits.
A + B + C = 2 Co + S
| A | B | C | Co | S |
|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 0 |
| 0 | 0 | 1 | 0 | 1 |
| 0 | 1 | 0 | 0 | 1 |
| 0 | 1 | 1 | 1 | 0 |
| 1 | 0 | 0 | 0 | 1 |
| 1 | 0 | 1 | 1 | 0 |
| 1 | 1 | 0 | 1 | 0 |
| 1 | 1 | 1 | 1 | 1 |
If you notice carefully, the Full Bit Adder above resembles a cat!
Our Mojo have 3 different sections:
- First section, the first 3 leds represent A, B, C values and the button below as its inputs. The last 2 leds represent Auto or Manual state and the button below is the input.
By default, the Mojo will be in Auto state. If the the button is on, it goes to Manual state and the 2 leds above it will light-up.
- Second section, the first 2 leds represent the expected sum and carrier of the A,B,C input
- Third section, the first 2 leds represent the detected output from the Full Bit Adder. The last 2 leds represent error which will light up if the Full Bit Adder is wrong or when the expected output is not the same with detected output.
Auto
In Auto mode, our FPGA will go through all 8 possible cases of A,B,C inputs to check our Full Adder
Manual
To switch to manual mode, toggle the button to on. We can see that 2 leds above the button light-up and we can input A,B,C as our desire.
Error detection
As you see, if the expected output is not equal to the expected output, the 2 led represents error will light up, which can be easily noticed.
- Strip Boards
- Wires
- MOJO V3
- IO-Shield
- SN74HC08N/AND gate
- CD74HC86E/XOR gate
- Led x2
- Switchs
- Battery 1.5V x4
- 12k Ohm resistor x3
- 470k Ohm resistor x2
- Ivan Christian - 1003056
- James A. Pohadi - 1002899
- Rachel Chua - 1003129
- Gou Yuanyuan - 1002972
- Wang Zijia - 1002885