Pro Mini Serial over USB

Development Boards Arduino
1

I’m going crazy over my Pro Mini. Spent way too many hours over the past few days trying to get Serial over USB to work.

I have the board hooked up to my MacBook and I’m able to upload sketches just fine. (I can see LEDs blink if I run the example in this link: https://learn.sparkfun.com/tutorials/pr … 1-blinkies) However, I can’t get any output on the serial over USB.

I’m connecting to /dev/tty.usbmodem14134131 when uploading sketches. When the unit exits the boot loader, /dev/tty.usbmodem1 appears. In my attempts to use the serial communications, I therefore switch to /dev/tty.usbmodem1 in the Arduino IDE and try to monitor the serial, but get nothing from the blinky-example in the link above.

I’ve tried different baud rates and I’ve also tried to use Minicom instead of the built-in serial monitor, all to no avail.

I’m probably making some silly mistake here, but I can’t figure out what, so I need some help. Any ideas?

2

I figured this out.

The boards were sold to me as 3.3V. Turns out they are actually 5V. After programming them as 5V they work just fine.

I do find it a bit weird though that it’s possible to program the boards as 3.3V ones and that the program actually works, except for external communications…