Pro Mini runs at half speed


Just bought a Pro Mini 5V from the internet that is supposed to run at 16MHz. No it seems to run at half speed (led is blinking once per 2 seconds in stead of once per second). I also have to set the serial monitor to 4800 baud while in the sketch, I use 9600 baud. Any idea what is happening here?

Are you sure they didn't send you a 3.3volt one? Those are spec'd to run at 8mhz. I don't have one to look at, but are there any markings on the resonator to indicate frequency? You might also ask the seller about it (who did you get it from?)

Thanks gpsmikey, That was it. It's now running as expected. I should have though of that myself :-( I cannot blame the seller for sure (a seller in The Netherlands). Maybe I messed things up myself.

Unless you hooked the chip up to an ISP programmer and changed the Low Fuse to use the internal resonator, or removed the 16mhz resonator and replaced it with an 8mhz one, you can safely blame the vendor ;-)