I2C Bridge CRT TV with Arduino
Overview
The I2C Bridge on CRT TV project focuses on designing a tool for testing and debugging slave devices on a main board using the I2C protocol. This bridge allows for efficient communication interception between the Arduino and the integrated circuit (IC) responsible for converting low-voltage video output to high-voltage output for a CRT (Cathode Ray Tube) TV.
Duration:
July 2021 - August 2021
Project Description
The goal of the project was to implement an I2C bridge solution that facilitates the debugging of the integrated circuit responsible for video processing on a CRT TV. The bridge intercepts the I2C communication between the video output IC and the Arduino, enabling real-time analysis and troubleshooting.
Key Features:
• I2C Communication Interception: Allows the Arduino to intercept and monitor communication between the video processing IC and other components using the I2C protocol.
• Video Signal Debugging: Focuses on the IC that converts low-voltage video signals into high-voltage signals compatible with a CRT display.
• C++ Code Implementation: Custom C++ code was developed for effective debugging of the video processing circuit by utilizing I2C data transmission.
• Pull-up Resistor Implementation: A pair of pull-up resistors were added to ensure proper voltage levels for the I2C communication, enabling stable and reliable data transfer.
Components Used:
• Arduino: Used as the main controller to manage I2C communication and interact with the video processing IC.
• I2C Protocol: The communication protocol used to interface with the video processing IC.
• Pull-up Resistors: Essential components for stabilizing the I2C signals.
Design and Implementation
- I2C Bridge Design:
The design allows the Arduino to intercept and control the I2C communication between the main board and the video processing IC. This enables monitoring, testing, and debugging of the video signal conversion process.
- C++ Code Development:
Custom C++ code was written to facilitate debugging by enabling real-time communication with the video processing IC, logging I2C traffic, and analyzing data flow.
- Pull-up Resistor Configuration:
To ensure proper signal integrity on the I2C bus, a pair of pull-up resistors were strategically placed in the circuit to maintain the required voltage levels for both high and low signals.
Sample C++ Code for I2C Bridge
Below is the basic Arduino code to intercept and monitor the I2C communication between the video processing IC and other components. This sample demonstrates how the Arduino can capture I2C traffic and log it for debugging purposes.
#include <Wire.h>
#define SLAVE_ADDRESS 0x50 // Change this to match your slave's I2C address
void setup() {
Serial.begin(9600); // Start serial communication for logging
Wire.begin(); // Initialize the I2C bus as master
Wire.onReceive(receiveData); // Set up an I2C receive handler
Wire.onRequest(requestData); // Set up an I2C request handler
}
void loop() {
// The Arduino will be continuously monitoring the I2C traffic
// Any I2C requests or data received will be handled by the handlers
delay(100); // Small delay to prevent overload
}
void receiveData(int byteCount) {
// This function is triggered when data is received from the slave
Serial.print("Data received: ");
while (Wire.available()) {
char c = Wire.read(); // Read each byte of data from the I2C bus
Serial.print(c); // Log the received data to the Serial Monitor
}
Serial.println();
}
void requestData() {
// This function is triggered when the master requests data from the Arduino
byte data = 0x42; // Example data to send back to master
Wire.write(data); // Send data back to the master
Serial.print("Sent data: ");
Serial.println(data, HEX);
}
Key Functions:
• Wire.begin(): Initializes the I2C communication as the master.
• Wire.onReceive(): Sets up a handler to process data received from the slave.
• Wire.onRequest(): Defines a handler to respond when the master requests data.
• Wire.read(): Reads incoming data from the I2C bus.
• Wire.write(): Sends data to the I2C bus.
How the Code Works:
• Data Reception: The receiveData() function handles the incoming data from the slave device, logging it to the Serial Monitor for analysis.
• Data Request: The requestData() function allows the Arduino to respond to data requests from the master device, sending back a simple byte as an example.
Wiring Setup:
-
Connect the SDA (Data line) and SCL (Clock line) from the Arduino to the corresponding pins on the I2C bus between the video processing IC and the master device.
-
Attach a pair of pull-up resistors (typically 4.7kΩ) to the SDA and SCL lines to ensure proper voltage levels for communication.
Usage
- Setup:
Connect the Arduino to the I2C bus between the integrated circuit (IC) and other components on the main board.
- Testing and Debugging:
The Arduino will capture and log the data being exchanged over the I2C bus, allowing for detailed analysis of communication between the IC and other devices. This provides insights into potential issues with the video processing pipeline.
- Code and Libraries:
• Ensure the appropriate I2C library for Arduino is installed.
• Upload the provided C++ code to the Arduino to begin intercepting and debugging the I2C communication.
Applications
• CRT TV Troubleshooting: Helps in debugging the video processing ICs used in CRT televisions by analyzing the I2C data.
• Embedded Systems Debugging: Can be adapted for testing other I2C-based systems, especially where communication with external slave devices needs to be monitored.
Future Work
Future iterations of this project could focus on improving the interface for data visualization, automating troubleshooting steps, and expanding the tool’s compatibility with other video signal processors.
License
This project is licensed under the MIT License. See the LICENSE file for more details.
This updated README.md includes a sample C++ code for the I2C Bridge on the CRT TV project. This code demonstrates how to intercept and monitor I2C communication between devices, which is the core functionality of the project.