Can I burn the core with just J-TAG? Can I buy core without a USB port?


I wonder how can I burn the core just with the J-TAG and st-link?

Can I buy the core without usb port?

Best regards,

The core doesn’t come without a usb port (as far as I know) but if you purchasing in a reasonable quantity, that might be possibly arranged. :slight_smile:

@will should have more information on this.

Hey @itayd100 yeah you can definitely flash the Core with just the JTAG Shield and ST-Link programmer. You can find more details at the link below about flashing a Core from scratch:

As far as buying a Core without a usb port, are you building something that requires a Core without a USB port? The large majority of our customers prefer to power and program their Core over USB, so we’re not currently considering manufacturing a USB-free variation of the Core.

Hey @will,

Yeah, I’m building a prototype and the USB port become a problem. There’s no cores without?

Sec, I follow the instructions on the link that you sent me. I did it with the ST-link combine with the dfu-utill. I tried to do it just with the St-link but no success. Can you help me? What program do you use? How I translate the duf-utill commands to the St-link program?

the beauty of the spark being an open source reference design is that you can roll up a version of the spark core without the USB port.
it would just require getting PCBs made and populating them…

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An even faster way to get a Core without a USB port would be to just use a soldering iron, rework gun, and/or some snips to physically remove the USB connector. Again, I’m not sure if you’re looking to literally just remove the USB port and keep everything else the same, or redesign other elements of the board.

dfu-util is a utility for flashing the Core over USB, so you probably don’t want to use those commands. Instead, you’re going to want to use the ST-Flash utility, which is discussed in step #3 of the tutorial I sent you to:

3.) Make sure you have st-flash installed, or have a copy of the ST-Link Utility software

You can find the software on their site if you're using windows:

If you're on mac / linux grab "st-flash" you can grab and build a tool yourself:

git clone

cd stlink




make install``

So, you’re going to want to use st-flash commands, not dfu-util commands if you’re flashing over JTAG using your terminal.

Hope that helps!

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