905 Keypad Calculator
905 : Keypad Calculator
- Author: Vidisha Chopra
- Description: A TinyTapeout keypad calculator that scans a 4x4 keypad and outputs the 8-bit calculation result.
- GitHub repository
- Open in 3D viewer
- Clock: 0 Hz
Keypad Calculator
How it works
This project implements a calculator for a 4x4 keypad. The keypad scanner drives the column lines and reads the row lines to detect which key is pressed. Digits are buffered, operators are stored, and the ALU computes the final result.
Supported operations:
- Addition
- Subtraction
- Multiplication
- Division
The 8-bit result is shown on the dedicated output pins.
How to test
- Apply reset.
- Press digit keys to enter the first operand.
- Press an operator key.
- Press digit keys to enter the second operand.
- Press equals.
- Observe the 8-bit result on
uo_out.
External hardware
- 4x4 matrix keypad
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | keypad row inputs | 8-bit calculator result | keypad column outputs |
| 1 | keypad row inputs | 8-bit calculator result | keypad column outputs |
| 2 | keypad row inputs | 8-bit calculator result | keypad column outputs |
| 3 | keypad row inputs | 8-bit calculator result | keypad column outputs |
| 4 | unused | 8-bit calculator result | unused |
| 5 | unused | 8-bit calculator result | unused |
| 6 | unused | 8-bit calculator result | unused |
| 7 | unused | 8-bit calculator result | unused |