The dwiBus library provides a structured and reliable UART communication protocol for multi-device networks. Designed for Arduino and ESP32 platforms, it simplifies data transmission between up to 255 devices with CRC error checking, packet management, and broadcast messaging capabilities.

• Supports up to 255 devices with individual addressing
• Broadcast messaging using address 0xFF
• Automatic packet splitting and reassembly for large data transmissions
• CRC-8 error control to detect data corruption
• Hardware and Software Serial support
• ACK support for reliable communication
• Dynamic memory management using the Response class

1. Download or Clone:
   https://github.com/dralicimen/dwiBus

2. Add Library to Arduino IDE:

   • Sketch > Include Library > Add .ZIP Library
   • Select the downloaded ZIP file.

3. Install Dependencies:

   • Ensure SoftwareSerial is available for Arduino platforms.

To connect multiple devices over UART using half-duplex communication, you need to share the TX and RX lines. Use 1K Ohm resistors or diodes to prevent data collisions. Below is a simple ASCII diagram:

Device 1            Device 2            Device 3
+---------+         +---------+         +---------+
|    TX ---+----+---+    TX ---+----+---+    TX   |
|    RX <--|----+---|--> RX <--|----+---|--> RX   |
|         [1K]      [1K]      [1K]               |
|              Common Bus                      |
|------------------ TX/RX BUS ------------------|

• Cathode (|<) connects to the TX pin of each device.
• Anode (>|) connects to the shared RX line.

#include <dwiBus.h>

// Initialize dwiBus with RX = 11, TX = 12, Control Pin = 13, Address = 0x02
dwiBus bus(11, 12, 13, 0x02);

void onPacketReceived(const Response& response) {
    Serial.print("Received from 0x");
    Serial.print(response.sender, HEX);
    Serial.print(": ");
    Serial.write(response.completeData, response.totalLength);
    Serial.println();
}

This example demonstrates communication between two devices using dwiBus.

#include <dwiBus.h>

// Initialize the dwiBus object
dwiBus bus(11, 12, 13, 0x02);  
Response* responsePtr = nullptr;

// Callback to handle incoming messages
void onPacketReceived(const Response& response) {
    if (responsePtr) delete responsePtr;  
    responsePtr = new Response(response);  

    Serial.print("Received from 0x");
    Serial.print(response.sender, HEX);
    Serial.print(": ");
    Serial.write(response.completeData, response.totalLength);
    Serial.println();

    // Send ACK to sender
    bus.sendPacket(response.sender, "ACK from 0x02");
}

void setup() {
    Serial.begin(9600);
    bus.begin(9600);
    bus.onPacketReceived(onPacketReceived);

    Serial.println("Client 2 (0x02) is ready.");
}

void loop() {
    if (bus.sendPacket(0x01, "Hello from 0x02")) {
        Serial.println("Message sent to 0x01.");
    } else {
        Serial.println("Bus busy.");
    }

    bus.handleReceive();  
    delay(5000);  
}

The Response class dynamically stores incoming data.

class Response {
public:
    char* completeData;         // Pointer to the complete data
    uint16_t totalLength;        // Total length of the data
    uint8_t sender;              // Sender's address
    unsigned long receiveTime;   // Timestamp of reception

    Response(uint16_t length);   // Constructor to allocate memory
    ~Response();                 // Destructor to free memory
};

• CRC Mismatch: If CRC fails, the packet is discarded with an error message.
• Bus Timeout: If the bus is busy, sending will fail with a timeout message.
• Broadcast Handling: Devices must ignore ACK responses to broadcast messages.

This project is licensed under the GNU GPL v3 License. For more information, see the LICENSE file.

Ali Çimen
GitHub: dralicimen
Email: cimenwd@gmail.com

• v1.0.0: Initial release with CRC error control and broadcast functionality.

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.