<aside> 💡 Unless you've soldered on a new SAMD51 microcontroller, it's likely the bootloader is already programmed for you.

</aside>

Flashing a new bootloader

Table of Contents

Requirements:

• [ ] Download and install Atmel Studio 7 (not required, but recommended)
• [ ] JTAG programmer with SWD interface (the SEGGER J-Link EDU mini work and cost $18)
• [ ] Download the .uf2 and .bin files from the SAM32 GitHub

Instructions:

1. With the requirements above satisfied, plug the JTAG programmer into your computer and open Atmel Studio 7.

2. Navigate to Tools → Device Programming, as shown:

   

3. Select the appropriate Tool and Device from the drop-down menus and click apply.

   ❗ make sure to choose the correct microcontroller part number. Visually check the part markings on the SAMD51 to confirm if it's theSAMD51x20.

   

4. Navigate to "Memories" on the left-hand side.

5. Uncheck the "Erase Flash before programming" box, and then click the "..." button, as shown:

   

6. Navigate to the directory you saved the GitHub firmware files, and change the file parameters from "Programming Files" to "Binary" and shown:

   

7. Select the .bin file downloaded previously and click the "Open" button:

8. Now make the following connections to the SAM32 board.

   ⭐ if you have a SAM32 v26 or greater, you can connect to the JTAG lines as shown here.

   Required Connections:

   • [ ] Main micro USB cable (to provide power)

     Note: it's good practice to use a multimeter and confirm 3.3V is present when the USB connection is made to the SAM32 board. If the voltage doesn't read 3.3V between "3V3" and "GND" you need to troubleshoot that first.

   • [ ] VTref (connected to 3V3)

   • [ ] TMS (connected to SWDIO)

   • [ ] TCK (connected to SWCLK)

   • [ ] GND (connected to GND)

9. With the connections made, return to Atmel Studio 7 and click the "Read" button. A device signature should populate. If an error appears, check connections and troubleshoot the specific error message.

   • Common Errors

   

10. After receiving a device signature, click the "Program" button. Programming should only take a few moments.

11. Successful bootloader programming will trigger the SAM32 board to reboot. After a few moments, the board should mount to the computer as a SAM32BOOT drive.

    

    Flashing the Firmware:

    ---

12. Drag the CircuitPython firmware .uf2 file downloaded previously to the SAM32BOOT drive:

    

13. As soon as the file is done transferring, the board will reboot again and mount as CIRCUITPY or and is now a functioning CircuitPython board. Congratulations! 🎉

    Note: now is a good time to load the default libraries to the lib folder as described in: Adding/Updating Libraries

Checking the bootloader: