Right — this is the bit that trips most people up, but it’s straightforward.
CH340 is not a “USB drive”. It’s the USB-to-serial chip driver your Arduino Nano clone uses so your computer can talk to it.
If the driver isn’t installed (or is wrong), the board won’t show up as a usable COM port in Arduino IDE.
🔧 What you need to do (CH340 setup)
🪟 Windows (most likely case)
1. Plug in your CosmicWatch v2
Use a data-capable USB cable.
2. Check Device Manager
Right-click Start →
Device Manager
Look under:
- Ports (COM & LPT)
You should see something like:
- “USB-SERIAL CH340 (COMx)” ✔ GOOD
OR if it’s broken:
- “Unknown device”
- or nothing appears ❌
📥 3. If CH340 is NOT showing properly
You need the driver installed.
Install CH340 driver:
Search and install:
- “CH340 driver WCH official”
After install:
- unplug Nano
- plug it back in
🔍 4. Confirm it worked
Back in Device Manager:
✔ Good result:
- “USB-SERIAL CH340 (COM3/4/5 etc.)”
That COM number is what Arduino IDE uses.
⚙️ 5. Select it in Arduino IDE
Go to:
- Tools → Port → select the COM port
Example:
- COM3 (CH340)
🚨 If you don’t see any COM port at all
Check these:
A. Bad USB cable (very common)
- Try another cable
- Must support data, not just charging
B. Wrong USB port/hub
- Plug directly into PC (not hub)
C. Clone uses different chip (less common)
Some Nano boards use:
- FTDI (different driver)
- CP2102 (Silicon Labs driver)
🧠 Quick mental model
Think of it like this:
- Arduino Nano = “radio telescope receiver”
- CH340 driver = “translator so your PC understands it”
- COM port = “frequency channel it appears on”
Without CH340, your computer can’t “hear” the board.
👍 Once CH340 is working
You can proceed to:
- selecting board: Arduino Nano
- selecting processor: ATmega328P (Old Bootloader often needed)
- uploading CosmicWatch firmware