GPIO Switch Controlled LED Logic (ARM7 LPC2129)

Project Overview

This project demonstrates basic GPIO input and output control using the ARM7 LPC21xx microcontroller. Two push-button switches are used to control two LEDs based on defined logic conditions.

The project focuses on understanding:

• GPIO input handling
• Bit manipulation
• Active-low switch logic
• Conditional control of multiple outputs

Objective

To implement switch-based conditional LED control logic using direct register-level programming in Embedded C.

Hardware

• LPC2129 (ARM7TDMI) Microcontroller
• 2 Push Button Switches
• 2 LEDs
• Regulated Power Supply

Software

• Embedded C
• Keil µVision IDE
• Flash Magic

Working Principle

Case 1:

When Switch 1 is pressed, only then Switch 2 functionality becomes active.

Case 2:

If Switch 2 is pressed (while Switch 1 is pressed):

• LED1 turns ON
• LED2 turns OFF

Case 3:

If Switch 2 is released (while Switch 1 is pressed):

• LED2 turns ON
• LED1 turns OFF

Additional Condition:

If Switch 1 is not pressed:

• Both LEDs remain OFF