How to Use SparkFun Serial Basic Breakout - CH340G: Examples, Pinouts, and Specs

The SparkFun Serial Basic Breakout is a compact and user-friendly USB-to-serial adapter board that facilitates communication between a computer and a microcontroller or other serial devices. It employs the CH340G chip to provide a reliable USB-to-serial interface. This breakout is particularly useful for programming devices that do not have a USB interface, such as certain Arduino boards, or for adding a serial port to your computer.

• Programming microcontrollers without onboard USB
• Serial communication for debugging purposes
• Bridging a USB connection to a serial device
• Providing a serial interface for Raspberry Pi or similar boards

• Voltage Levels: 3.3V and 5V compatible
• Current Rating: 50mA
• Interface: USB to Serial UART
• Supported Baud Rates: Up to 115200 bps
• Connectivity: Micro-USB

1. Connecting to a Microcontroller:

   • Connect the GND pin to the ground of the microcontroller.
   • Connect the TX-O pin to the RX pin on the microcontroller.
   • Connect the RX-I pin to the TX pin on the microcontroller.
   • Optionally, connect the DTR pin to the reset pin on the microcontroller if auto-reset is desired during programming.

2. Powering the Breakout:

   • The VCC pin can be connected to either a 3.3V or 5V power supply, depending on the logic level required by the microcontroller.

3. Connecting to a Computer:

   • Use a Micro-USB cable to connect the breakout board to a computer's USB port.

4. Driver Installation:

   • Install the CH340G drivers on your computer if they are not already installed. Drivers are available on the SparkFun website.

5. Serial Communication:

   • Use a serial terminal program to communicate with the microcontroller through the breakout board.

• Ensure that the logic levels (3.3V or 5V) match between the breakout board and the microcontroller to avoid damage.
• Always disconnect the breakout board from the USB port before making or altering connections to the circuit.
• Use quality USB cables to prevent connection issues.

• Driver Installation Problems: Ensure that the correct drivers for the CH340G chip are installed on your computer.
• No Serial Communication: Check all connections, ensure that the correct COM port is selected, and verify that the baud rates match between the devices.
• Device Not Recognized: Try a different USB cable or port, and ensure that the breakout board is not physically damaged.

• If the device is not recognized, reinstall the CH340G drivers and restart your computer.
• For communication issues, double-check the wiring, especially the TX and RX connections, as they are often mistakenly reversed.
• Ensure that the breakout board is not being powered at a voltage level that is incompatible with the connected microcontroller.

Q: Do I need to install drivers for all operating systems? A: Drivers are typically required for Windows. Linux and macOS usually have built-in support for the CH340G chip.

Q: Can I use this breakout board to program an Arduino Pro Mini? A: Yes, the SparkFun Serial Basic Breakout can be used to program an Arduino Pro Mini and other similar boards that lack a USB interface.

Q: What is the purpose of the DTR pin? A: The DTR pin can be used to automatically reset certain microcontrollers during the programming process, allowing for a smoother workflow.

Q: Is the breakout board compatible with 5V systems? A: Yes, the breakout board can be configured to work with both 3.3V and 5V systems by connecting the VCC pin to the appropriate power supply.

// This example demonstrates basic serial communication between the SparkFun Serial Basic Breakout
// and an Arduino UNO. The Arduino will echo any received characters back to the serial terminal.

void setup() {
  // Begin serial communication at a baud rate of 9600:
  Serial.begin(9600);
}

void loop() {
  // Check if data has been received:
  if (Serial.available() > 0) {
    // Read the incoming byte:
    char incomingByte = Serial.read();
    
    // Echo the byte back to the serial terminal:
    Serial.write(incomingByte);
  }
}

Remember to select the correct COM port and baud rate in your serial terminal program to match the settings in your Arduino sketch.