The CH340E is a USB-to-UART bridge controller, often used for connecting USB interface s to serial communication (RS232/TTL) devices. It belongs to the WCH (Nanjing QinHeng) family of products. This chip allows for USB-to-serial communication and is widely used in embedded systems and communication interfaces.
Pinout and Packaging
The CH340E typically comes in a QFN-32 package, which consists of 32 pins. Here's a detailed explanation of the pin functions and how the device operates. Below is a list of each pin, its function, and usage:
Pin Function Table for CH340E (QFN-32 Package)
Pin No. Pin Name Function Description 1 VCC Power supply input (typically 3.3V or 5V, depends on system) 2 GND Ground connection 3 TXD Transmit data pin for UART (TX, output to peripheral) 4 RXD Receive data pin for UART (RX, input from peripheral) 5 DTR Data Terminal Ready (output, used in flow control) 6 DSR Data Set Ready (input, used in flow control) 7 RTS Request To Send (output, used in flow control) 8 CTS Clear To Send (input, used in flow control) 9 VBUS USB voltage detection pin (used for USB power presence detection) 10 ID Identification pin for USB OTG (not used in all applications) 11 DP USB data positive signal (USB data line) 12 DM USB data negative signal (USB data line) 13 VCC Power supply input (same as pin 1) 14 RST Reset pin (used to reset the chip, active low) 15 SUSPEND USB suspend signal (used in low-power modes) 16 I2C_SCL I2C clock line (optional, for I2C communication) 17 I2C_SDA I2C data line (optional, for I2C communication) 18 A0 Address pin (used for address selection in some systems) 19 A1 Address pin (used for address selection in some systems) 20 A2 Address pin (used for address selection in some systems) 21 A3 Address pin (used for address selection in some systems) 22 NC No connection (reserved or unused pin) 23 NC No connection (reserved or unused pin) 24 NC No connection (reserved or unused pin) 25 NC No connection (reserved or unused pin) 26 NC No connection (reserved or unused pin) 27 NC No connection (reserved or unused pin) 28 NC No connection (reserved or unused pin) 29 NC No connection (reserved or unused pin) 30 NC No connection (reserved or unused pin) 31 NC No connection (reserved or unused pin) 32 NC No connection (reserved or unused pin)Note: Some pins are marked as NC (No Connection), meaning they have no function or are reserved for future use in certain versions of the chip.
FAQs for CH340E
Here are 20 frequently asked questions about the CH340E, formatted in a Q&A style:
Q: What is the function of the VCC pin in the CH340E? A: The VCC pin provides the power supply to the CH340E chip, typically operating at 3.3V or 5V, depending on the system.
Q: How should I connect the GND pin of the CH340E? A: The GND pin should be connected to the ground of the system to complete the electrical circuit.
Q: What is the purpose of the TXD pin? A: The TXD pin is used for transmitting data from the CH340E to other devices via UART.
Q: What is the function of the RXD pin? A: The RXD pin is used for receiving data from external devices via UART.
Q: What does the DTR pin do? A: The DTR pin is used for flow control in serial communication, signaling that the device is ready to communicate.
Q: What is the purpose of the DSR pin? A: The DSR pin is used in flow control and indicates whether the device is ready to communicate.
Q: What does the RTS pin control? A: The RTS pin is used to request permission to send data, indicating readiness for communication.
Q: What does the CTS pin do? A: The CTS pin is used to indicate whether the device is ready to receive data, as part of the flow control.
Q: What is the function of the VBUS pin? A: The VBUS pin detects whether USB power is present and is used in power management.
Q: What is the ID pin used for? A: The ID pin is used in USB OTG applications for device role identification (Host or Device).
Q: What are the DP and DM pins for? A: The DP and DM pins are the USB data positive and negative lines used for data transfer over USB.
Q: What is the role of the RST pin? A: The RST pin is used to reset the CH340E chip. It is an active low reset.
Q: What is the SUSPEND pin used for? A: The SUSPEND pin is used to put the device into a low-power state during USB suspend mode.
Q: How does I2C communication work with the CH340E? A: The I2CSCL and I2CSDA pins are used for I2C communication, where SCL is the clock line, and SDA is the data line.
Q: What is the purpose of the address pins (A0, A1, A2, A3)? A: These pins are used for address selection in some applications, particularly for USB devices that require multiple addresses.
Q: Why are some pins marked as NC? A: NC (No Connection) pins are reserved for future use or are not connected in the current configuration.
Q: What voltage should I apply to the VCC pin? A: The VCC pin should be supplied with either 3.3V or 5V, depending on your system requirements.
Q: Can the CH340E operate at different voltages? A: Yes, the CH340E can operate at 3.3V or 5V, but you must ensure the correct voltage level is supplied to the VCC pin.
Q: What should I do if my device doesn't recognize the CH340E? A: Ensure that the proper drivers for CH340E are installed, and verify the correct wiring, including the power supply and USB connections.
Q: How can I use the CH340E for USB-to-serial communication? A: The CH340E provides UART interface signals (TXD, RXD) for serial communication. Connect it to your microcontroller or serial device, and use appropriate software to manage data exchange.
This description covers the pinout, the detailed functions of each pin, and answers to frequently asked questions to help in understanding the usage and capabilities of the CH340E. Let me know if you need any more details!
