Hello,
I am considering getting the 3V Arduino Pro Mini 328 (https://www.adafruit.com/products/2377 ) and also getting the FTDI Friend (https://www.adafruit.com/product/284 ) and have a couple of questions. First, it is my understanding that I can use the FTDI Friend to load a program from the Arduino IDE onto the Pro Mini. I just have to connect it correctly from the Friend to the Pro Mini. Is this correct?
Second, the FTDI Friend says it is for either 5V or 3.3V. If I use it on a 3.3V Pro Mini do I have to cut the jumper on the back and set it up to use the 3.3V setting? What changes will I have to make to use it with a 3.3V Pro Mini if any? Are there detailed instruction available so that I can look them over before making the purchase?
My third question is that I would like to attach a 9V battery to the Pro Mini for a wearable project. Can I just attach it directly to the Pro Mini? If not what do I need to do to step the voltage down? What are the possible gotchas for doing this?
3V Arduino Pro Mini 328 and the FTDI Friend
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- adafruit_support_mike
- Posts: 67446
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Re: 3V Arduino Pro Mini 328 and the FTDI Friend
That's correct.hij wrote:First, it is my understanding that I can use the FTDI Friend to load a program from the Arduino IDE onto the Pro Mini. I just have to connect it correctly from the Friend to the Pro Mini. Is this correct?
Yes. The Pro Mini's FTDI connector is connected to the board's 3.3v rail, so you want to modify it for 3.3v output on the VCC pin. Cut the trace between the 5v pad on the back and add a solder jumper across the 3.3v pads.hij wrote:Second, the FTDI Friend says it is for either 5V or 3.3V. If I use it on a 3.3V Pro Mini do I have to cut the jumper on the back and set it up to use the 3.3V setting?
We have more information about the FTDI Friend in the tutorial: https://learn.adafruit.com/ftdi-friend
Yes. The Pro Mini has a built-in voltage regulator that can accept input voltages up to 12v. Just make sure you connect it to the RAW pin.hij wrote:My third question is that I would like to attach a 9V battery to the Pro Mini for a wearable project. Can I just attach it directly to the Pro Mini?
- hij
- Posts: 12
- Joined: Mon Apr 20, 2015 1:11 pm
Re: 3V Arduino Pro Mini 328 and the FTDI Friend
Excellent, thank you!
- hij
- Posts: 12
- Joined: Mon Apr 20, 2015 1:11 pm
Re: 3V Arduino Pro Mini 328 and the FTDI Friend
I received my Pro Mini 3.3V and the FTDI friend. I was able to cut the 5v jumper on the FTDI friend and solder the 3.3v jumper without any problems. When I went to connect the FTDI friend to the Pro mini I noticed that the labels on the pins are different.
When I look at the pro-mini and read the labels on the pin from black to green the left most pin has no label and then it goes GND, VCC, RXI, TXO, and no label.
When I look at the FTDI friend from black to green it reads GND, CTS, VCC, TX, RX, RTS.
It looks like the RXI and TXO pins are reversed and the lack of labels on the left and right pins on the pro-mini is a bit confusing. I was under the impression that I could just plug the FTDI friend straight into the Pro-mini by lining up the colour codes (black to black and green to green). Is this correct or do I have to swap the lines??? I have not done anything yet becaue of my confusion.
When I look at the pro-mini and read the labels on the pin from black to green the left most pin has no label and then it goes GND, VCC, RXI, TXO, and no label.
When I look at the FTDI friend from black to green it reads GND, CTS, VCC, TX, RX, RTS.
It looks like the RXI and TXO pins are reversed and the lack of labels on the left and right pins on the pro-mini is a bit confusing. I was under the impression that I could just plug the FTDI friend straight into the Pro-mini by lining up the colour codes (black to black and green to green). Is this correct or do I have to swap the lines??? I have not done anything yet becaue of my confusion.
- hij
- Posts: 12
- Joined: Mon Apr 20, 2015 1:11 pm
Re: 3V Arduino Pro Mini 328 and the FTDI Friend
I did some poking around and found this:
http://shallowsky.com/blog/hardware/pro ... riend.html
According to this web page I just have to match green to green and then black to black. Before trusting random person on the interwebz, I want to ask the random people on these here interwebz. Is the blog post above correct?
http://shallowsky.com/blog/hardware/pro ... riend.html
According to this web page I just have to match green to green and then black to black. Before trusting random person on the interwebz, I want to ask the random people on these here interwebz. Is the blog post above correct?
- adafruit_support_mike
- Posts: 67446
- Joined: Thu Feb 11, 2010 2:51 pm
Re: 3V Arduino Pro Mini 328 and the FTDI Friend
That's correct.
Serial/UART connections work like a telephone: TX is the part you talk into and RX is the part you listen to. To make the connection work, you attach one device's TX pin to the other's RX pin.
Serial/UART connections work like a telephone: TX is the part you talk into and RX is the part you listen to. To make the connection work, you attach one device's TX pin to the other's RX pin.
- andrewa
- Posts: 145
- Joined: Mon Oct 19, 2009 9:53 pm
Re: 3V Arduino Pro Mini 328 and the FTDI Friend
How about using a TTL-232R-3V3? A bit of the Google turned up this discussion:
http://forum.arduino.cc/index.php?topic=22999.0
So, if I have a TTL-232R-3V3, which has 5V on the VCC pin, I'm thinking that using this directly would be a bad idea, since the 6 pin connector has a VCC pin that isn't hooked to the RAW pin, and I'll have to make a bit of a converter so only five of the pins get connected to the Arduino, and the 5V pin from the TTL-232R-3V3 goes to the RAW pin.
Sound right?
http://forum.arduino.cc/index.php?topic=22999.0
So, if I have a TTL-232R-3V3, which has 5V on the VCC pin, I'm thinking that using this directly would be a bad idea, since the 6 pin connector has a VCC pin that isn't hooked to the RAW pin, and I'll have to make a bit of a converter so only five of the pins get connected to the Arduino, and the 5V pin from the TTL-232R-3V3 goes to the RAW pin.
Sound right?
- adafruit_support_mike
- Posts: 67446
- Joined: Thu Feb 11, 2010 2:51 pm
Re: 3V Arduino Pro Mini 328 and the FTDI Friend
That would be this one: https://www.adafruit.com/products/70
It plugs onto the FTDI pins at the end of a Micro.
It plugs onto the FTDI pins at the end of a Micro.
- andrewa
- Posts: 145
- Joined: Mon Oct 19, 2009 9:53 pm
Re: 3V Arduino Pro Mini 328 and the FTDI Friend
The only addendum I can add here is that don't forget to check the 3.3 V 8 MHz option on download! I tried with another setting, and the 'blink' code ran, but when working with Serial.print() and the like I got junk back on the serial monitor. Changing it to the correct setting made it happy.
Please be positive and constructive with your questions and comments.