I'm trying to get set up to develop for the Adafruit Trinket on a Mac running the OS X El Capitan beta (10.11.2 beta) with Xcode and embedXcode. I've got the Arduino IDE downloaded from arduino.cc installed as /Applications/ArduinoCC.app. I'm able to build and run the Blink example using the Arduino IDE and Xcode appears to also work (it knows about the Trinket, and claims to successfully load the code) but it does not blink. The red LED on pin 1 just continues to pulse at about 10 Hz as if it was waiting to for code to be loaded.

Any ideas what could be going on or how I can troubleshoot further?


  1. I've made the changes to avrdude.conf suggested by the folks at Adafruit to accommodate the erase timing requirements of the Trinket.
  2. I got a response on the Adafruit forum that suggested going back to 1.6.5 as many people have been reporting problems with 1.6.6 breaking things. However, I can program the board using 1.6.6.
  • Maybe F_CPU is set incorrect. Try increasing the delay between turning the led on and off, and see if the led blinks slower. – Gerben Nov 22 '15 at 13:43

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