Onboard USB Port Precautions

Overview

This document explains the USB interface functions, connection methods, and DIP switch configuration for the Fly-D8 mainboard.

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Host Computer Connection Instructions

Core Connection Limitation

The Fly-D8 mainboard can only communicate with the host computer for Klipper via the Type-C USB interface.

Connection Requirements:

• Use a high-quality Type-C data cable to ensure stable data transmission.
• It is recommended to avoid excessively long cables (not exceeding 1.5 meters).
• Connect to a standard USB-A port on the host computer.

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USB Interface Function Description

Integrated Architecture Explanation

Functionally Independent, Physically Integrated

The RS232 serial port and USB expansion function on the Fly-D8 mainboard are two completely independent functional modules, only physically integrated on the mainboard.

The Fly-D8 mainboard is equipped with two USB interfaces, each with different functions:

1. Type-C USB (Host Interface)

• Function: Dedicated for connecting to the host computer.
• Power Switch: There is a USB-5V>EN switch next to it, used to control the 5V power output of the Type-C interface.
  • Pressed Down: Turns ON the 5V output from the Type-C interface (can power the host computer).
  • Popped Up: Turns OFF the 5V output from the Type-C interface.

Host Connection Recommendation

For regular use, it is recommended to keep the USB-5V>EN switch popped up (5V output OFF) to avoid:

1. Conflict with the host computer's own 5V power supply.
2. Potential power backflow issues.
3. Protecting the host computer's USB interface.

Only press the switch (turn 5V output ON) when the host computer needs additional power from the Type-C interface.

2. USB-A (Device Expansion Interface)

• Function: Used for expanding peripherals, supports connecting:
  • USB cameras
  • USB drives/storage devices
  • Other standard USB devices
• Independent Module: The USB expansion function is a completely independent module, only physically integrated on the mainboard.

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USB/RS232 Mode Switching

Function Selection Explanation

The Fly-D8 mainboard uses a DIP switch to select between the USB expansion function or the RS232 serial port function on the same physical interface.

DIP Switch Settings

DIP Direction	Function Mode	Corresponding Interface	Typical Use
Right	USB Expansion Mode	USB-A Interface ❷	Connect USB devices like cameras, USB drives, etc.
Left	RS232 Serial Port Mode	RS232 Interface ❸	Connect toolboards supporting RS232 communication.

Mode Switching Precautions

1. Mutually Exclusive: USB expansion and RS232 serial port functions cannot be enabled simultaneously; only one can be selected.
2. Firmware Compatibility: When using RS232 function, the toolboard must support RS232 communication and have the RS232 firmware flashed.
3. Independent Modules: The RS232 serial port and USB expansion are two independent functional modules, only physically integrated on the mainboard.

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Common Issues and Troubleshooting

Issue 1: Host Computer Cannot Recognize D8 Mainboard

Troubleshooting Steps:

1. Confirm connection is made via the Type-C interface.
2. Check the status of the USB-5V>EN switch next to the Type-C interface (for regular use, it is recommended to be popped up/5V output OFF).
3. Check the quality of the data cable; try replacing it.
4. Verify that the host computer's USB port is functioning normally.
5. Check if the mainboard is receiving normal power supply.

Issue 2: USB Device Not Recognized

Troubleshooting Steps:

1. Confirm the DIP switch is set correctly (Right for USB Expansion Mode).
2. Check USB device compatibility.
3. Verify the USB device works normally on another host.
4. Ensure the USB-5V>EN switch for the Type-C interface is popped up (5V output OFF).

Issue 3: RS232 Communication Abnormal

Troubleshooting Steps:

1. Confirm the DIP switch is set correctly (Left for RS232 Serial Port Mode).
2. Check the RS232 cable connection, ensure TX/RX are cross-connected.
3. Check for common ground (ensure GND connection between mainboard and toolboard).
4. Verify the toolboard supports RS232 communication and has the corresponding firmware flashed.

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Usage Recommendations

1. Type-C Connection: When connecting to the host computer, it is recommended to keep the USB-5V>EN switch popped up (5V output OFF) to avoid power conflicts.
2. Function Selection: Choose between USB expansion or RS232 serial port function based on needs; they are independent modules.
3. RS232 Connection: When connecting to an RS232 toolboard, switch the DIP switch to the left.
4. USB Expansion: When connecting USB devices like cameras, switch the DIP switch to the right.
5. Safe Operation: All mode switching operations must be performed with the power OFF.
6. Firmware Compatibility: Before using the RS232 function, confirm the toolboard has the RS232 firmware flashed.