Hello - I have a 3.3v pro mini. I am about down with the first project with it and it will be powered by a 5v supply but I still need program testing and changing. I do this with a ftdi board that has power coming from a usb. I would think this is very common and it could I could have the external power at the same time as the ftdi power but I want to check to make sure I down fry something. Does this work or should I remove the power cables on the ftdi?
Thank you,
Anthony
Just remove the V+ from the FTDI to the Arduino. The FTDI connections to the Arduino would be TX to RX, RX to TX and ground to ground (and DTR to Reset through cap, if so equipped).
Thank you for the quick response. Okay I did that and just plugged in the pro mini. As expected, the led on the board did not light. I then measured the voltage at vcc to ground and got a small voltage. Is this normal?
What is the power supply and how is it connected? A diagram of all of the connections would be easier to interpret.
aiannar974:
As expected, the led on the board did not light. I then measured the voltage at vcc to ground and got a small voltage. Is this normal?
Small might be normal, but then if its really small or halfway between small and really small ...........
Hint - If you have read a voltage with a multimeter, tell people what the reading is, 'small' is meaningless.
Hello - I have a 3.3v pro mini. I am about down with the first project with it and it will be powered by a 5v supply but I still need program testing and changing. I do this with a ftdi board that has power coming from a usb. I would think this is very common and it could I could have the external power at the same time as the ftdi power but I want to check to make sure I down fry something. Does this work or should I remove the power cables on the ftdi?
Thank you,
Anthony
This is a good question.
Obliviously the ProMini needs to be powered.
You removed the Vcc pin on the FTDI connector, correct?
You still need to power the ProMini from another source, i.e. the 'RAW' pin.
I guess that I should have added: external power supply to +5V or Vin (as appropriate) and ground to reply #1.
Thank you everyone- small is 1.1 volts with nothing with power connected other that ftdi with vcc not connected. Since I started this thread I connected 5v to raw. I have ran power through that and the board powers on. I have not put the ftdi cable back in yet. The 5v is 7805 circuit powered by a 12v wall wart. This project requires required 3.3, 5 and 12 volts.
I connected 5v to raw.
The raw input feeds the onboard 5V regulator. The on board 5V regulator needs at least 7V (2 volts above the regulated output) to be able to regulate properly. Feed regulated 5V to the 5V pin, not raw.
This is a 3.3v board. I have read 3.4v to 12 on the raw pin
Sorry, I missed the 3.3V. Following several threads and got mixed up. So, yes, 5V to the raw input.