FTDI, VCC, and the Arduino Pro Mini

This project has been the first one where I've used a 3.3V Pro Mini.  There's some important things to keep in mind regarding power input.

• Power input on RAW can be 3.3V - 12V.  It will be regulated to 3.3V.  Specifically, VCC will be 3.3V
• Power input from the FTDI connector is not regulated. If you are using a 5V FTDI connector VCC will be 5V!
• In general you can get by with using a 5V FTDI cable on a 3.3V Pro Mini.  It's out of spec but is generally accepted as working.
• You can't use a 5V FTDI if you are powering a 3.3V device from VCC!
• 
  

Here's a workaround if you're stuck with a 5V cable and want to use it to power a Mini that has a 3.3V device on VCC.

Remove the VCC line from the FTDI cable.  Gently lift the plastic tab and the  wire with attached connector will slide out.  If you have an extra single-ping cable protector (take one off a female-female breadboard wire if you've got one) you can insert the VCC connector in there.  You could also use some small heatshrink to cover it.  You could let it go bare, but be careful not to short it out.

Attach the FTDI cable (minus the removed VCC) to the Pro Mini as usual.  Attach FTDI VCC to Pro Mini RAW.

Check the voltage on Pro Mini VCC.  It should be 3.3V, regulated by the Pro Mini.

The Sparkfun product page has this note in the comments:

Q: Are the rx/tx lines 5V tolerant? I want to know if it is possible to program this with a 5V FTDI board, without needing to get an additional 3.3V FTDI just for this board. 

A: Yes, the only difference in the 3.3V and 5V Pro Minis is the crystal and the voltage regulator. Since the FTDI bypasses the regulator the only difference is the speed the run at. The ATMega328 is fine at 5V. Keep in mind if you have 3.3V on VCC and 5V on the I/O pins that is technically out of spec (you shouldn't put more than VCC on the I/O pins), but will probably work as well. Keep in mind that the 5V FTDI will put 5V on the VCC line, so make sure you don't have any 3.3V only devices connected when you do this.

blogodex = {"toc" = ["FTDI", "Arduino"], "idx" = {"ArrBot", "Electronics", "Voltage", "No Hack Too Cheap"]};

MacOS FTTI Installation

Here's the installation guide. On page 3, use this link to get the dmg and select the appropriate file for your MacOS version.  10.9 seems to work with the release for 10.8.  You want the one that creates the virtual com port.



Here's the error I was getting:

avrdude: Send: 0 [30]   [20]
avrdude: Send: 0 [30]   [20]
avrdude: Send: 0 [30]   [20]
avrdude: ser_recv(): programmer is not responding
avrdude: stk500_recv(): programmer is not responding 

blogodex = {"idx" : ["FTDI", "MacOS FTDI Drivers"]};

Attaching an FTDI connector to an Arduino

 Here's how to hook up an FDTI connector to an Aduino card.  You need one of these when you're programming an Aduino that doesn't have a USB connector.  In this case, it's an Aduino Mini mounted on a MultiWii Paris board.

The FTDI connector plugs into the six pins on the top of the card. You don't need to care about the pin names, but note the BLK and GRN labels.

 Plug a mini USB cable (technically a "USB 2.0 Mini Type B 5 position")  onto the FTDI card and attach it to your computer.  Your computer should load the correct driver.

The FTDI connector is not keyed, so it's easy to attach it backwards.  Nothing bad will happen, but it won't work. There are BLK and GRN labels here as well.  Line up the labels with the Arduino and make the six pins are going into the six sockets.

Your software will have some menu for picking the serial port and baud rate.  On my windows box it's COM6, and on my Mac it's some odd name with "USB" in the middle.

BTW, I don't know what BLK and GRN stand for.  I'm assuming it's "black" and "green", and that some ancient connector used wires of those colors.  In any case, all modern FTDI connectors are cards, and they're all labelled with BLK and GRN.

FTDI and AVR cables

Here's a quick brain dump of the differences between FTDI and AVR programming cables.

• Arduino things use the FTDI adapter.  FTDI is basically a serial/usb converter. 
• FTDI is a company, their main product is a serial/usb chip.
• The Arduino boot loader has code to handle the ftdi loading process.
• Shown is the Solarbotics FTDI basic breakout.

• The KK Board is more hard-core, non-arduino, "pure" atmel.
• AVR programmer is used to "flash" the on-board chip memory, like writing an eprom.
• If you want to take an atmel chip and make it into an arduino chip, you would use an AVR programmer and flash the arduino boot loader.
• Likewise, you use an AVR programmer to flash the kkboard software onto the atmel chip.
• Daddy87 has a great tutorial here.

• "Name brand" AVR programmers are, ironically, more expensive than the HK KKboard .
• But, lots of cheap vendors on ebay, all based on the open-source hardware design of Thomas Fischl:  http://www.fischl.de/usbasp
• This one is from ProtoStack.