In a previous post (here) I might have mentioned in passing that the method in use wasn’t particularly suitable for longer term use. Which was entirely true, and is exactly why I’m now back to bore your socks off once more!
To get that off to a good start, the same disclaimer as before applies, this is intended as a rough guide only, and I make no assurance for how accurate the information is. Modifications such as this to your hardware could damage or destroy it. Apply common sense where necessary and I take no responsibility for any failures resulting from following or not following my instructions. (Worked for me though, so I’m assuming it will for you too.) Secondary disclaimer – soldering irons are hot. Don’t try to eat them.
So before we begin, you’ll likely want the following:
- Same as before: A Pi, an SD card with a bootable OS image, a micro USB to USB cable, a mini USB to USB cable, Putty!
- An FTDI breakout board that lends itself to soldering. (link)
- A soldering iron, and some solder (hurray!)
- A connector which will fit on top of the Pi’s GPIO pins.
- Wire Strippers.
- Something to cut through the connector cables (pliars or wire cutters).
Now that you have yourself once more kitted out, the first thing you’ll have to do if you took the bigger breakout board rather than the Basic 3.3v version from the last post, is ensure you set it up to work with 3.3v, not 5v. In the image below, highlighted on the FTDI breakout is the location you need to add the solder bridge, by melting some solder and connecting the 3.3v jumper (lower in the image) to the middle jumper you can correctly set up the breakout board to operate at that voltage level.
In that image, they haven’t yet been bridged, there needs to be a bridge of conducting material between the two jumpers for it to work. Don’t blow up your board!
The next thing you’ll need is the cable to affix to the GPIO pins on the Pi. If you have an old motherboard or spare computer lying around that you can scavenge parts from, those from the front-panel USB will be perfect for our needs, it should be a cable that looks something like this:
Note that one of the holes on this connector is blocked off, we don’t care about this, so feel free to break it open so that you can fit it cleanly onto your board if you want to. Usuaully these cables have a female connector on both ends, if you cut through it with your wire cutters in the middle, you can re-use the other half for another project.
At this point, you have the end with the connector, and another end with insulated wiring. You can strip off the insulation from the ends of the wires (only as much as you need) to prepare them for being soldered onto the FTDI breakout board. At this point you can also cut away any wires you dont need which would have hung uselessly from your connector. So you should have something like this:
In my picture, by following the information on this page you can see that the wires are connected as follows on the Pi:
- Green – Ground
- White – TX (Transmit)
- Red – RX (Receive)
As before, the TX from the Pi connects to the RX on the FTDI board and the RX on the Pi connects to the TX on the FTDI board, by process of elimination Ground still connects to Ground. Now you can remove your connector from the Pi for easier manipulation during soldering, and begin feeding the stripped ends of the wires into their correct locations on the end of the FTDI breakout board. The result of that effort should be something like this, but with better soldering:
Yeesh, that’s messy – I know. I’m not very dextrous.
Right, now assuming you’ve not crossed any solder trails, and that you’ve correctly bridge the solder to make to board play nice with 3.3v, and assuming you wired up the correct GPIO pins, and that you sacrificed the goat correctly – you should be able to plug the Mini USB cable into your computer, and have it automagically install the driver for the FTDI.
Once that’s done, you can open up Putty, set it to serial mode running at 115200 baud on whatever COM/ttyXXX that the FTDI decided to put itself on, turn off hardware flow control open up the connection and then finally plug in your micro USB. At which point the board shouldn’t explode, but should start spewing out boot information for you to read.
Isn’t that nicer than the previous solution? Yes, of course it is.