By mattmunee -
- Sat Feb 28, 2015 8:39 am #180114
I know this post is a bit old, but I wanted to post on my status. I ran into the exact same problem. After reading this forum, I had a similar problem. I was using an 3.3V FTDI adapter from LowPowerLab that has worked interchangeably with a similar Sparkfun adapter on other projects. However, in this case, it did not. I was using an Arduino Pro Mini 3.3V microcontroller. Switching to the Sparkfun FTDI adapter fixed the problem. Be careful with your level shifting!