Arduino Pro Mini: run standalone

Using Arduino IDE 1.x
1

Hello!

I'm working on a project with an Arduino Pro Mini from Sparkfun and I'm facing a strange problem.
My board has a 5v power supply for Arduino, my goal is to run it "stand alone", without a PC connection but:

  • if I run my sketch with Arduino's USB->Serial adapter connected, everything works fine;
  • if I try to run it without PC connection, the onboard led flashes every about 1 second and my sketch doesn't run.

I simply connected Vcc and GND from Arduino Pro Mini to my power supply... do I need to connect also RESET?
From Pro Mini schematics (http://arduino.cc/en/uploads/Main/Arduino-Pro-Mini-schematic.pdf) it seems it has an onboard pull-up resistor so I thought it was ok to leave the two RESET pins unconnected, am I wrong?

What could change if I run Arduino with serial connection?

Thanks!

2

Your Mini should run if you connect regulated 5V to VCC (+) and GND (-) or if you connect 7 to 12V to RAW (+) and GND (-).

3

Hi John

thanks for your answer... that's exacly how I connected my Pro Mini... and the voltage is ok (5V with a tester between pin Vcc and Gnd)...
So I don't need to connect RST pin, do I?
What could it mean the rapid flash of on board led if I don't connect serial cable?