SparkFun Qwiic Joystick

SparkFun Qwiic Alphanumeric Display Application

Overview

This application demonstrates integration between NetBurner's RTOS platform and the SparkFun Qwiic Alphanumeric Display (COM-16919). The program initializes both network services and the I2C display, then continuously shows a running seconds counter on the 4-digit alphanumeric display.

Hardware Requirements

• NetBurner development board with I2C/Wire support
• SparkFun Qwiic Alphanumeric Display (COM-16919)
• Qwiic connector cable or appropriate I2C wiring connections

Key Features

• Network Integration: Full network stack initialization with HTTP web server
• I2C Communication: Direct interface with HT16K33 display controller
• Real-time Display: Live system uptime counter (0-9999 seconds, cycling)
• Connection Verification: Automatic display connectivity checking
• Development Diagnostics: Built-in system diagnostics for debugging

Application Architecture

Initialization Sequence

1. Network Setup
   • Initialize NetBurner network stack
   • Enable system diagnostics for development
   • Wait up to 25 seconds for active network connection
   • Start HTTP web server on default port 80
2. Display Configuration
   • Initialize I2C Wire interface
   • Configure HT16K33 display controller
   • Verify display connection status
   • Display initial "NBRN" message
   • Pause 1 second before entering main loop
3. Main Operation Loop
   • Monitor system seconds counter continuously
   • Update display with current seconds (modulo 10000)
   • Output status indicators to console

Core Components

SerialIf Serial;    // Debug output interface
TwoWire Wire;       // I2C communication bus
HT16K33 disp;       // SparkFun display controller

Display Operations

The application utilizes the SparkFun Alphanumeric Display library:

• begin() - Initialize display hardware
• isConnected(0) - Verify I2C connection
• print() - Display text and numeric values

Usage Instructions

Hardware Setup

1. Connect the SparkFun Qwiic Alphanumeric Display to your NetBurner board
2. Use either Qwiic connector cable or manual I2C wiring (SDA/SCL)
3. Ensure proper power connections

Software Deployment

1. Compile the application using NetBurner development tools
2. Upload the compiled firmware to your NetBurner board
3. Monitor serial console for initialization status

Expected Behavior

Serial Console Output:**

Web Application: SparkFunAlphaDisplay
NNDK Revision: [version number]
Begin True/false
Connected True/false
. . . . (status dots every second)

Display Sequence:**

1. Initial display shows "NBRN" for 1 second
2. Continuous seconds counter (0000-9999, then cycles back to 0000)
3. Updates every second with current system uptime

Code Structure

Main Function Flow

void UserMain(void *pd)
{
    // Network and system initialization
    init();
    EnableSystemDiagnostics();
    WaitForActiveNetwork(TICKS_PER_SECOND * 25);
    StartHttp();
    
    // Display setup and verification
    Wire.begin();
    disp.begin();
    disp.isConnected(0);
    
    // Main operational loop
    while (1) {
        // Monitor and display seconds counter
    }
}

Timing Considerations

• Network timeout: 25 seconds maximum wait
• Display update rate: Every 1 second
• Initial display pause: 1 second
• Console status output: Every second

Development Notes

Production Considerations

• Remove EnableSystemDiagnostics() for production builds
• Consider adding error handling for network failures

Display Limitations

• 4-digit alphanumeric format limits counter to 0-9999
• Counter automatically cycles back to 0000 after reaching 9999
• Display uses modulo arithmetic: Secs % 10000

Network Features

• HTTP web server runs on port 80
• Network diagnostics enabled for development
• Connection monitoring with timeout protection

Troubleshooting

Common Issues

Display Not Initializing**

• Check I2C connections (SDA/SCL pins)
• Verify power supply to display

• Confirm I2C address conflicts

  Connection Status False**

• Verify proper I2C wiring
• Check display power connections

• Ensure correct I2C address (default for HT16K33)

  Network Timeout**

• Verify network configuration
• Check Ethernet cable connections

• Confirm network settings in NetBurner configuration

  No Display Updates**

• Verify main loop execution
• Check that seconds counter is incrementing
• Confirm I2C communication is functioning

Debug Information

The application provides comprehensive debug output:

• Application name and NNDK revision
• Display initialization status
• Connection verification results
• Real-time status indicators (dots every second)

Dependencies

Required Libraries

• NetBurner RTOS core libraries
• SparkFun Alphanumeric Display library
• Standard I2C/Wire communication libraries
• Network stack libraries

Technical Specifications

Display Controller

• Chip: HT16K33 LED controller
• Interface: I2C communication
• Display Type: 4-digit alphanumeric
• Update Rate: 1 Hz (every second)

Network Services

• Web Server: HTTP on port 80
• Connection Timeout: 25 seconds
• Diagnostics: Development mode enabled

System Integration

• Platform: NetBurner RTOS
• Communication: I2C (Wire library)
• Timing: RTOS tick-based scheduling

Related Documentation

• SparkFun Qwiic Alphanumeric Display (COM-16919) datasheet
• NetBurner RTOS documentation
• HT16K33 LED controller specifications
• I2C communication protocols