STM32 Based USB Keypad and Calculator Project
Development Period : 2024.08 ~ 2024.11
- MCU : STM32F401RET6
- Displsy : ST7789 1.9" TFT LCD
- Battery : Li-Po 500mAh 3.7V
- Interface: USB (for keypad mode and charging)
- Switches: Cherry MX compatible mechanical switches
( Kailh hot-swap sockets )
- Maximum expression length: 70 characters
- Calculator supported Operations
Basic arithmetic : +, -, ×, ÷
Parentheses : (), {}, []
Trigonometric functions : sin, cos, tan
Planned support for : asin, acos, atan, log, ln
- Mode 0 : Calculator
- Mode 1 : USB Keypad
| USB C | Power S/W | Mode S/W | Function | Power source |
|---|---|---|---|---|
| 0 | 0 | X | Power off | - |
| 0 | 1 | 0 | Calculator mode | Battery |
| 0 | 1 | 1 | - | - |
| 1 | 0 | X | Power off | Battery charge |
| 1 | 1 | 0 | Calculator mode | USB + Battery charge |
| 1 | 1 | 1 | USB Keypad mode | USB + Battery charge |
