Modular Digital Dice using LPC2129

A bare-metal, two-player digital dice game built on the NXP LPC2129 (ARM7) microcontroller. This project goes beyond basic text output by utilizing Custom Character Generation (CGRAM) to draw physical dice faces directly on a standard 16x2 Alphanumeric LCD.

It relies on Hardware Timers for pseudo-random number generation and the Vectored Interrupt Controller (VIC) to handle instantaneous player inputs.

Key Features

• Custom LCD Graphics: Utilizes the HD44780's CGRAM to map and print real graphical dice faces (1 to 6 dots) on the LCD.
• Hardware RNG: Leverages the fast-running Timer 0 counter (T0TC) modulo 6 to generate a truly unpredictable pseudo-random dice roll.
• Interrupt-Driven: Uses External Interrupts (EINT0 and EINT1) via the VIC for instant, non-blocking player inputs.
• Modular Architecture: The codebase is split into 5 distinct source/header files, demonstrating professional embedded software design principles.

File Structure

This repository is organized into a clean, modular 5-file architecture (excluding this README) to separate hardware abstraction from application logic:

File Name	Description
📄 main.c	Contains the core application loop, Interrupt Service Routines (ISRs) for Players 1 & 2, and the CGRAM lookup tables for drawing the dice faces.
📄 LCD_functions.c	The abstraction layer for the display. Handles LCD initialization, sending commands, writing raw data, and printing strings.
📄 delay.c	Contains precise, hardware timer-based (Timer 0) delay functions used for LCD timing and debouncing.
📄 UART_config.c	Handles UART initialization and configuration for receiving the number (byte).
📄 Setup.h	The central header file linking the modules together. Contains necessary macros, port definitions, and function prototypes.

Hardware Setup & Wiring

• Microcontroller: LPC2129 (ARM7TDMI-S)
• Display: 16x2 HD44780 Compatible LCD
• Player Inputs: * Player 1 Button: Connected to EINT0 (External Interrupt 0)
  • Player 2 Button: Connected to EINT1 (External Interrupt 1)

Note: Ensure the push buttons are properly pulled up/down based on your specific hardware configuration. The code sets EXTPOLAR = 0x00 (Active Low).

How It Works?

1. On startup, the MCU initializes the LCD, configures the UART, sets up the fast-running Hardware Timer (RNG), and maps the External Interrupts.
2. The LCD displays the headers P1: and P2: waiting for user input.
3. When a player presses their respective button, the hardware triggers an interrupt.
4. Inside the ISR, the system captures the exact current microsecond value of the running timer (T0TC), performs a modulo 6 operation, and adds 1 to determine the dice value (1-6).
5. The main loop detects the flag set by the ISR, prints the numerical value, and calls the CGRAM_print function to draw the corresponding dotted dice face on the screen.

Contributing

Contributions, issues, and feature requests are welcome! If you want to port this to another ARM architecture or add features like win-tracking via EEPROM, feel free to submit a pull request.