Slightly distractedly, I went and connected 5V to the 3.3V pin on my DFRobot Bluno (the pins are right next to each other!)

The magic smoke leaked out of the AMS1117 3.3V regulator in a neat little puff. The sketch that was loaded on the board still runs fine, but the Bluno is no longer recognised by my Macbook Pro when I plug it into USB (I have tried different ports and different cables; they're all fine—it's the USB on the Bluno that's fried.)

In an attempt to repair it, I've replaced the AMS1117 (check the third paragraph of that tutorial—ha!) with an LF33ABV; this went well and I'm now getting a stable 3.3V on the 3.3V pin. Check out my handiwork:

Bluno with original AMS1117 SMD 3.3V regulator replaced by a through-hole LF33ABV

However, the Bluno still isn't being recognised by the USB ports on my Mac.

Is there another way to upload new sketches to the Bluno? Theoretically you can do so over BTLE, but you need another Bluno to act as the "peripheral" and I don't have one to hand. I have various other Arduinos laying about if that helps.

  • 1
    Since the CC2540 is powered using the 3.3v, you might have also blown that chip by giving it 5v instead of the 3.9V, which is its maximum rating. Does BT still work? (Great fix with the regulator though; look awesome)
    – Gerben
    Sep 20 '14 at 21:10
  • 1
    I think I might have :-(. The Bluno isn't showing up on any of the BTLE-sniffer apps I have on the iPhone. Sep 21 '14 at 17:08

Upload via ICSP. See those six pins next to the regulator you so expertly tacked on? Those are the ICSP pins. You'll need a second controller or programmer to do it.


  • Funnily enough I remembered I had a USBtinyISP laying around. With it (and these instructions I've successfully managed to upload a new sketch to the board. Now to see if I can talk to it via BTLE... Sep 21 '14 at 16:49

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