SOMRT1061 Pin IRQ Example

SOMRT1061 PinIrq Application

Overview

This application demonstrates how to use pin interrupt functionality on the SOMRT1061 platform. It implements a real-time edge detection system that monitors pin state changes and provides visual feedback through an LED indicator.

Location

examples/PlatformSpecific/SOMRT1061/PinIrq

Supported Platforms

• SOMRT1061

Application Description

The PinIrq application showcases interrupt-driven GPIO monitoring using NetBurner's RTOS capabilities. The program:

• Monitors pin 30 for edge transitions (both rising and falling edges)
• Uses a semaphore-based notification system to handle interrupts safely
• Provides real-time feedback through pin 78 (LED output)
• Tracks and reports the total number of detected transitions
• Demonstrates proper interrupt handling in an RTOS environment

Key Features

Hardware Configuration

• Input Pin: Pin 30 (configured as input with interrupt capability)
• Output Pin: Pin 78 (LED indicator)
• Edge Detection: Both rising and falling edges

Software Architecture

• Interrupt Service Routine: Minimal ISR that posts to a semaphore
• Task-based Processing: Dedicated task handles the actual pin change logic
• Thread-safe Communication: Uses OS semaphores for inter-task communication
• Real-time Monitoring: Continuous status reporting every second

How It Works

1. Initialization: The application configures pin 30 as input and pin 78 as output
2. Interrupt Setup: Registers an interrupt handler for pin 30 that triggers on both edges
3. Event Handling: When a pin transition occurs:
   • The interrupt handler (NotifyFunc) posts to a semaphore
   • The PinChangeTask wakes up and processes the event
   • The transition counter is incremented
   • The LED state is updated to follow the input pin state
4. Status Reporting: Main loop continuously prints the current transition count and pin state

Code Structure

Main Components

• NotifyFunc(): Interrupt service routine that signals pin changes
• PinChangeTask(): Task that handles pin change processing
• UserMain(): Main application loop with status reporting
• Semaphore (NotifySem): Synchronization primitive for interrupt handling

Global Variables

• Transitions: Counter tracking total number of edge detections
• irq_pin_num: Pin number for interrupt monitoring (pin 30)

Usage

1. Connect a switch or signal source to pin 30
2. Connect an LED to pin 78 to observe the output
3. Compile and upload the application to the SOMRT1061
4. Monitor the serial output to see transition counts and pin states
5. Toggle the input on pin 30 to observe the LED response and counter updates

Expected Output

The application will continuously output status information in the format:

Running SOMRT1061 PinIrq
{We have detected X edges pin is currently: Y

Where X is the total transition count and Y is the current pin state (0 or 1).

Technical Notes

• The interrupt handler is kept minimal to avoid issues in interrupt context
• All significant processing is performed in task context for safety
• The LED output inverts the input state, providing clear visual feedback
• System diagnostics are enabled for debugging purposes

Dependencies

• NetBurner RTOS
• Pin interrupt functionality
• Standard NetBurner GPIO libraries