A debug LED (You can convert it into a watchdog blinky later to verify that your main loop/1ms interrupt or whatever you're using is still running) is something that I would consider pretty mandatory for an exploratory board. Hello World on your new PCB does not need to be as complex as an LCD. You could repurpose a backlight controlling MOSFET for this purpose if you don't want to add the real components.
I'm assuming you're giving yourself some form of breakout for your extra pins - An LCD screen is great, and I understand the desire to keep it simple, but there's little that can go wrong simply by adding a trace to nowhere, and nowhere can become somewhere someday. Even if you don't want to add real headers, some test points (in the form of staggered rows of .05x.1" copper pads) will let you solder and hot glue some wires on later. This doesn't have to be a big deal. I'd put some jumpers/resistors on those lines, so you can add some 1k resistors to protect your pins from being shorted or hit with ESD if you decide to do so. This also gives you the ability to pull any of your other pins high or low if later you find this is necessary!
One thing that I do on a first board is add a lot of vias. Vias are your friends when making modifications (assuming you're getting this done at a PCB house and don't have to drill them yourself). If you've got two vias on every trace, even if you don't change sides with your trace, you can cut the trace later with an Xacto and run 30-ga wire wrap wire between the traces that need to be swapped (Make sure your vias are big enough for this, though). You can also add 0805 0-ohm jumpers (solder bridges are cheap; you don't need to buy components) and solder wires to the pads later if you don't like the via method. Probably won't be necessary, but it's cheap/free insurance.
Oh, and connect the LCD/USB setup first, then tack wires on temporarily from your working breadboard to make sure that the externals are working.
The Launchpad is much, much cheaper than pretty much any other development kit you'll find. Many dev kits are several hundred dollars - How much are you willing to spend?
In my opinion, a dev kit should:
- Not be much more expensive than the components which were used to manufacture it. Some manufacturers put significant markup on their kits, imagining that they have their buyers locked in. They don't. If a kit is ridiculously priced, I buy a different one.
- Not lock you into a toolchain, and really should have an open-source and free toolchain available. The Launchpad does miss this point, but if he's interested in PICs and MSP430s, he'll have MPLAB installed already. For some tools, you won't find this option anywhere.
- Have some on-board peripherals and connectors, but should also make all of the microcontroller pins available with jumper or solder blob options, preferably through breadboard-friendly .1" pitch connectors.
Luminary Micro (aka TI/Stellaris) makes some evaluation kits which fit that bill today. I have the LM3S6965, which satisfies each of my above criteria, and has the components you specified: LCD, Ethernet, USB, and Cortex-M3. If you're reading this next Christmas, you'll have to re-evaluate the options.
In your search for an assortment of components, you should consider three things:
- What he already has. I can't help you on this one.
- What is in assortments that are available from places like Sparkfun and Adafruit (and elexp). Sometimes, one of these will fit the bill and have a quantity discount. Other times, these will have a selection markup, and be more expensive than buying individually from a major distributor.
- What he needs for his specific discipline. There are related questions about Equipment, Robotics, Components in general, and ICs to Interface with Microcontrollers.
That should get you started on a component search.
As for hobbyist magazines, I'd strongly recommend Circuit Cellar. It's a good deal more advanced than Nuts and Volts, but shouldn't be over his head if he's already looking into ARM processors and high-voltage stuff. In fact, Nuts and Volts might be too simple at times, but Circuit Cellar will never be too basic. The goal is always to improve, right? Jerrry [sic] from Slashdot posted a good overview of the magazine options a while back that I just found when trying to remember how to spell Elektor, another option to consider.
But before you buy anything, consider what you want it to mean to him. If you buy him components, they'll go in the parts cabinet and be put into projects over time, and your impact will probably be forgotten. For an example outside of the electronics realm, would you rather he buy you socks or a pretty scarf? Socks are more basic to your hobby of keeping warm, but when you wear the scarf you'll think of him, and when you wear the socks you won't. With that motivation, ignoring the technical evaluations of dev kits, components, and magazines, I recommend that you look for something that could cause him to think of you. A subscription to a magazine would be good (for 30 seconds a month, then, if he's like me, he'd be distracted by the articles...), but a tool might be better. You didn't mention that he had a bench power supply or multimeter - These would be tools that would last a long time, wouldn't become obsolete, and would be used every time he sat down at his bench.
Sorry for the long answer - I've been thinking about what to put on a wish list for Christmas for my girlfriend.
Best Answer
This really depends on the chips you are using - you didn't specify which one you got. Typically you would need at least a crystal, decoupling caps and reset logic. The programming interface might be a simple JTAG interface.
But all of this should be stated in the chips data sheet.
Update (for the STM32F407):
Look at the following pages in the data sheet
You won't need a reset circuit (it's integrated - see page 23) or an oscillator (the integrated 16MHz oscillator is selected on startup, see page 22). So using a LQFP144 breakout board (like the one from futurlec(see bottom of page) might really be enough.
You can also look at the schematic of the STM32F4DISCOVERY board (see it's user manual, page 33. What you see there is the basic circuit - and it even contains the external crystals.