Hi everyone, I have an Arduino Pro Mini. The seller says that it´s the 5V/16MHz version.
However, I am having some problems with it. It seems to be a mix between the 3v3 and 5V version.
I have done somel tests and these are the results:
When running it from 5V FTDI I obtain 5V in Vcc pins. Arduino runs properly, but at 8MHz. (I´ve tested it measuring the time that lasts blink program configured to a 16MHz board. It doubles the expected.
When running it from 9V battery (in RAW pin), I obtain 3.3V in VCC pin. That´s a problem for me because I need 5V for some sensors attached to the Arduino.
When running it from 5V FTDI I obtain 5V in Vcc pins. Arduino runs properly, but at 8MHz. (I´ve tested it measuring the time that lasts blink program configured to a 16MHz board. It doubles the expected.
Hi,
Try choosing the 8 Mhz option in the IDE (It worked for me).
Regards
srnet:
Its a Pro Mini with a 3.3V regulator (see 5 & 6)
What can I do?
Send it (Pro Mini) back for replacement.
There is probably some other stuff to, but I would go for 1.
I didn´t understand why I was running it with 5V in the VCC pin (with FTDI) and it didn´t burn. But I think that I have the solution. I had 5V in the VCC pin but, after that, the voltage is shifted to 3.3 before going to the ATMega328.
However, trying to get a refund is the right solution, I will try to do it.
Thank you!
unmonoqueteclea:
Yes yes, this is the solution for obtaining correct timing, but the problem with the sensors that need 5V doesn´t disappear.
Hi,
The ones I bought had a soldering option to feed them either from 3.3 or 5.0 Volts. I chose the 5 V option -to adequate feed the displays and have a 5 V range on them- and compiled the sketch at 8 Mhz.
They are so cheap that many times it is not worthwhile to ask for refunding.
On the other hand, the ones made by sparkfun work fine.
It is very common for sellers to mix up the 5v/16Mhz and 3.3v/8Mhz ones - the manufacturers almost never mark which is which on the boards, so it's a very easy mistake to make. Typically the boards have checkboxes on the back for voltage and speed, but IME they're never marked like that (at least in the case of cheap clones, which is all I buy because of how many boards I wire up for one-off projects. I think this is the big benefit of cheap clones - they're cheap enough that you don't have to extract the board from your project to reuse). Same problem with 433mhz vs 315mhz RF modules.
The Vcc pin is tied right to the Vcc rail (I think through a diode), so if you apply a voltage other than the spec'ed voltage on that pin, it will run at that voltage. (Among other things, this is helpful for running straight off a 3.7v LiPo battery). Only when powered via Vin or Raw (whichever your board calls it - I've seen both designations used. At least one of the official boards uses "Raw" for the external power input, despite the fact that it doesn't really make any sense.