Solving the Avrdude Error: A Comprehensive Guide to Fixing the Missing USBtiny Device Issue (0x1781/0xc9f)

In this guide, we will discuss the Avrdude error and provide a step-by-step solution to fix the missing USBtiny device issue (0x1781/0xc9f). This error occurs when programming microcontrollers using the USBtinyISP programmer and the Avrdude software. If you've encountered this error, follow the steps in this guide to resolve the issue and get back to programming your microcontrollers.

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Understanding the Avrdude Error

The Avrdude error related to the missing USBtiny device (0x1781/0xc9f) occurs when the Avrdude software fails to detect the USBtinyISP programmer. This can happen due to several reasons, such as faulty hardware, incorrect driver installations, or issues with the software itself.

Before diving into the step-by-step guide, it's essential to understand the components involved:

  • USBtinyISP - A low-cost USB AVR programmer that supports a wide range of microcontrollers. It's commonly used for programming Arduino boards and other AVR-based microcontroller projects.
  • Avrdude - A command-line software that allows you to program microcontrollers using various programming hardware, including the USBtinyISP.

Now that you have a basic understanding of the involved components, let's explore the step-by-step guide to fix the Avrdude error.

Step-by-Step Guide to Fixing the Missing USBtiny Device Issue

Step 1: Check the Hardware Connections

Before troubleshooting the software, ensure that your hardware connections are correct. Check the following:

  1. The USBtinyISP is securely connected to your computer using a USB cable.
  2. The microcontroller is correctly connected to the USBtinyISP.
  3. Power is supplied to the microcontroller, either from the USBtinyISP or an external power source.

Step 2: Verify the Device Manager

Open the Device Manager on your computer and check if the USBtinyISP is listed under "Universal Serial Bus controllers" or "Other devices." If you see a yellow exclamation mark or it's listed under "Other devices," there might be an issue with the drivers.

Step 3: Install the USBtinyISP Drivers

If the issue is related to the drivers, follow these steps to install the USBtinyISP drivers:

  1. Download the USBtinyISP drivers from the Adafruit website.
  2. Unzip the downloaded file and locate the "usbtinyisp_libusb-win32_1.2.1.0" folder.
  3. Right-click on the USBtinyISP entry in the Device Manager, and select "Update driver."
  4. Choose "Browse my computer for driver software" and navigate to the previously mentioned folder.
  5. Confirm the installation and restart your computer if prompted.

Step 4: Update Avrdude Configuration

If the issue persists, you might need to update the Avrdude configuration. Open the "avrdude.conf" file (located in the Avrdude installation folder) in a text editor and search for the "usbtiny" entry. Update the "vid" and "pid" values to "0x1781" and "0xc9f," respectively. Save the changes and restart Avrdude.


1. What is the Avrdude error code (0x1781/0xc9f)?

The Avrdude error code (0x1781/0xc9f) indicates that the Avrdude software cannot detect the USBtinyISP programmer connected to your computer. This can happen due to hardware issues, incorrect driver installations, or software configuration problems.

2. Can I use other programming hardware instead of USBtinyISP with Avrdude?

Yes, Avrdude supports a wide range of programming hardware, including USBasp, AVRISP mkII, and more. You can find the complete list of supported programmers in the Avrdude documentation.

3. How can I check if my microcontroller is supported by USBtinyISP?

USBtinyISP supports most AVR microcontrollers with ISP (In-System Programming) capability. You can check your microcontroller's datasheet or consult the Adafruit USBtinyISP product page for more information.

4. Can the Avrdude error be caused by a faulty USBtinyISP programmer?

Yes, a faulty USBtinyISP programmer can cause the Avrdude error. If you've followed the steps in this guide and the issue persists, consider testing your programmer on another computer or using another USBtinyISP programmer to verify if the problem is hardware-related.

5. Can I use Avrdude on different operating systems?

Yes, Avrdude is available for various operating systems, including Windows, macOS, and Linux. You can find installation instructions and download links on the Avrdude website.

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