br4yd3n-g/usb-cdc-library

USB CDC DLL

Overview

This DLL provides an interface for controlling USB CDC (Communications Device Class) devices on Windows. It supports a range of functionalities, including reading from and writing to CDC devices, configuring serial parameters, and managing control line states.

Features

• Open and close connections to USB CDC devices
• Read from and write to CDC devices asynchronously
• Configure and retrieve serial communication parameters (baud rate, parity, data bits, stop bits)
• Manage control lines (DTR, RTS)
• Set and get line coding
• Set flow control parameters (XON/XOFF, RTS/CTS, DTR/DSR)
• Send break signals

Functions

bool OpenCDCDevice(const char* devicePath);

Opens a connection to a USB CDC device.

Parameters:

• devicePath: Path to the device (e.g., \\.\COM3).

Returns:

• true on success, false otherwise.

void CloseCDCDevice();

Closes the connection to the USB CDC device.

bool StartWriteToCDCDevice(const char* data, size_t length);

Starts an asynchronous write operation to the CDC device.

Parameters:

• data: Pointer to the data buffer to write.
• length: Length of the data to write.

Returns:

• true if the operation was started successfully, false otherwise.

bool StartReadFromCDCDevice(size_t bufferSize);

Starts an asynchronous read operation from the CDC device.

Parameters:

• bufferSize: Size of the buffer to allocate for reading.

Returns:

• true if the operation was started successfully, false otherwise.

bool CheckWriteStatus();

Checks if the asynchronous write operation has completed.

Returns:

• true if the write operation is complete, false otherwise.

bool CheckReadStatus(char* buffer, size_t* bytesRead);

Checks if the asynchronous read operation has completed and retrieves the read data.

Parameters:

• buffer: Pointer to the buffer to store read data.
• bytesRead: Pointer to the variable to store the number of bytes read.

Returns:

• true if the read operation is complete and data is available, false otherwise.

bool SetCDCDeviceTimeouts(DWORD readTimeout, DWORD writeTimeout);

Sets timeouts for read and write operations.

Parameters:

• readTimeout: Read timeout in milliseconds.
• writeTimeout: Write timeout in milliseconds.

Returns:

• true if timeouts were set successfully, false otherwise.

void CancelOperations();

Cancels any ongoing read or write operations.

bool SetSerialParams(DWORD baudRate, BYTE parity, BYTE dataBits, BYTE stopBits, BOOL xonXoffInput, BOOL xonXoffOutput, BOOL dtrControl, BOOL rtsControl);

Sets serial communication parameters.

Parameters:

• baudRate: Baud rate.
• parity: Parity (e.g., NOPARITY).
• dataBits: Number of data bits (5, 6, 7, or 8).
• stopBits: Number of stop bits (e.g., ONESTOPBIT).
• xonXoffInput: Enable XON/XOFF input flow control.
• xonXoffOutput: Enable XON/XOFF output flow control.
• dtrControl: Enable DTR control.
• rtsControl: Enable RTS control.

Returns:

• true if parameters were set successfully, false otherwise.

bool GetSerialParams(DWORD* baudRate, BYTE* parity, BYTE* dataBits, BYTE* stopBits, BOOL* xonXoffInput, BOOL* xonXoffOutput, BOOL* dtrControl, BOOL* rtsControl);

Gets current serial communication parameters.

Parameters:

• baudRate: Pointer to store the baud rate.
• parity: Pointer to store parity.
• dataBits: Pointer to store the number of data bits.
• stopBits: Pointer to store the number of stop bits.
• xonXoffInput: Pointer to store XON/XOFF input flow control state.
• xonXoffOutput: Pointer to store XON/XOFF output flow control state.
• dtrControl: Pointer to store DTR control state.
• rtsControl: Pointer to store RTS control state.

Returns:

• true if parameters were retrieved successfully, false otherwise.

bool SetDtr(bool enable);

Sets or clears the DTR (Data Terminal Ready) control line.

Parameters:

• enable: true to set DTR, false to clear DTR.

Returns:

• true if the control line state was set successfully, false otherwise.

bool SetRts(bool enable);

Sets or clears the RTS (Request to Send) control line.

Parameters:

• enable: true to set RTS, false to clear RTS.

Returns:

• true if the control line state was set successfully, false otherwise.

void SetLineCodingHandlers(SetLineCodingFn setFn, GetLineCodingFn getFn);

Sets custom handlers for line coding operations.

Parameters:

• setFn: Function pointer for setting line coding.
• getFn: Function pointer for getting line coding.

bool SetLineCoding(DWORD baudRate, BYTE parity, BYTE dataBits, BYTE stopBits);

Sets the line coding parameters using the custom handler if provided.

Parameters:

• baudRate: Baud rate.
• parity: Parity.
• dataBits: Number of data bits.
• stopBits: Number of stop bits.

Returns:

• true if the line coding was set successfully, false otherwise.

bool GetLineCoding(DWORD* baudRate, BYTE* parity, BYTE* dataBits, BYTE* stopBits);

Gets the line coding parameters using the custom handler if provided.

Parameters:

• baudRate: Pointer to store the baud rate.
• parity: Pointer to store parity.
• dataBits: Pointer to store the number of data bits.
• stopBits: Pointer to store the number of stop bits.

Returns:

• true if the line coding was retrieved successfully, false otherwise.

bool SetControlLineState(BOOL dtr, BOOL rts);

Sets the control line state.

Parameters:

• dtr: Enable or disable DTR.
• rts: Enable or disable RTS.

Returns:

• true if the control line state was set successfully, false otherwise.

bool GetControlLineState(BOOL* dtr, BOOL* rts);

Gets the current state of the control lines.

Parameters:

• dtr: Pointer to store the DTR state.
• rts: Pointer to store the RTS state.

Returns:

• true if the control line state was retrieved successfully, false otherwise.

bool SendBreak();

Sends a break signal on the communication line.

Returns:

• true if the break signal was sent successfully, false otherwise.

bool SetFlowControl(BOOL xonXoffInput, BOOL xonXoffOutput, BOOL rtsCts, BOOL dtrDsr);

Sets flow control parameters.

Parameters:

• xonXoffInput: Enable XON/XOFF input flow control.
• xonXoffOutput: Enable XON/XOFF output flow control.
• rtsCts: Enable RTS/CTS flow control.
• dtrDsr: Enable DTR/DSR flow control.

Returns:

• true if flow control parameters were set successfully, false otherwise.

Future support

• Mac
• Linux
• Android
• IOS

Example

Here is a basic example demonstrating how to use the DLL in a C++ application.

Example Usage

#include <iostream>
#include <windows.h>
#include "usb_cdc_dll.h" // Include the DLL header file

// Define custom line coding handlers
bool CustomSetLineCoding(DWORD baudRate, BYTE parity, BYTE dataBits, BYTE stopBits) {
    // Implement custom logic here
    std::cout << "Custom setting line coding: BaudRate=" << baudRate << ", Parity=" << (int)parity << ", DataBits=" << (int)dataBits << ", StopBits=" << (int)stopBits << std::endl;
    return true; // Return success
}

bool CustomGetLineCoding(DWORD* baudRate, BYTE* parity, BYTE* dataBits, BYTE* stopBits) {
    // Implement custom logic here
    if (baudRate) *baudRate = 9600;
    if (parity) *parity = NOPARITY;
    if (dataBits) *dataBits = 8;
    if (stopBits) *stopBits = ONESTOPBIT;
    return true; // Return success
}

int main() {
    HINSTANCE hDll = LoadLibrary("usb_cdc_dll.dll");
    if (!hDll) {
        std::cerr << "Failed to load DLL." << std::endl;
        return 1;
    }

    // Define function pointers
    typedef bool (*OpenCDCDeviceFn)(const char*);
    typedef void (*CloseCDCDeviceFn)();
    typedef bool (*SetLineCodingHandlersFn)(SetLineCodingFn, GetLineCodingFn);

    // Get function pointers
    OpenCDCDeviceFn OpenCDCDevice = (OpenCDCDeviceFn)GetProcAddress(hDll, "OpenCDCDevice");
    CloseCDCDeviceFn CloseCDCDevice = (CloseCDCDeviceFn)GetProcAddress(hDll, "CloseCDCDevice");
    SetLineCodingHandlersFn SetLineCodingHandlers = (SetLineCodingHandlersFn)GetProcAddress(hDll, "SetLineCodingHandlers");

    if (OpenCDCDevice && CloseCDCDevice && SetLineCodingHandlers) {
        // Set custom line coding handlers
        SetLineCodingHandlers(CustomSetLineCoding, CustomGetLineCoding);

        // Open a CDC device (example device path)
        if (OpenCDCDevice("\\\\.\\COM3")) {
            std::cout << "Device opened successfully." << std::endl;

            // Set serial parameters
            if (SetSerialParams(9600, NOPARITY, 8, ONESTOPBIT, TRUE, TRUE, TRUE, TRUE)) {
                std::cout << "Serial parameters set successfully." << std::endl;
            } else {
                std::cerr << "Failed to set serial parameters." << std::endl;
            }

            // Close the device
            CloseCDCDevice();
            std::cout << "Device closed successfully." << std::endl;
        } else {
            std::cerr << "Failed to open device." << std::endl;
        }

        // Free the DLL
        FreeLibrary(hDll);
    } else {
        std::cerr << "Failed to get function pointers from DLL." << std::endl;
    }

    return 0;
}