Duff,
Sparkfun has a nice little tutorial which is geared more toward electronics, but uses the same processor as the Arduino boards for his lectures.
Ladyada has an Arduino specific tutorial, which I'll be running through as soon as I get mine. And the
Arduino site has a booklet which tries to cover everything. It gets spread a little thin, but has lots of links for more info.
From my industrial control days, a PLC can run up to $10,000 and have remote i/o, networking, etc. They are usually programmed with ladder logic, a visual language based on wiring diagrams which all the old maintenance men were used to reading. They can also be programmed with other languages. The programming software usually cost $ from the hardware mfr. I looked at using a a micro PLC first, since I am used to ladder logic. But by the time I added analog, high-speed counters, etc, the cost was around $300. And I still had to buy the software.
I'm new to microcontrollers, but I'll share what I've found so far (please correct me if I'm off base folks): The Atmel AVR and Microchip PIC microcontrollers seem to be the most popular. There are even clones of them available.
One of their websites claims you can program their chips with any language. But the reality seems to be you're pretty much limited by the availability of a compiler for each language. I've seen C, BASIC and one other language compilers. The Arduino platform has a free Development Environment supporting the Wiring language, which is a superset of C. You can also use straight C directly in it. AVR libraries and drivers are in C, so I think that pretty much limits the AVR programming to C. I would assume Arduino's could be programmed with other AVR tools (but you know what happens when you assume
) It looks like they use BASIC for the smaller PIC chips, and they use C on the bigger ones.
Atmel claims the same code will run on any chip in the AVR line. I'm not sure about PIC chips' portability.
It looks like we can use serial/usb to program the Arduino because there is already software installed (the bootloader) which will handle the communications. With no bootloader, or smaller boards with no serial/usb, the program gets loaded via the ttl port, which requires a "programmer" to convert RS232 to ttl. I know the small, popular BASIC Stamp PIC chip can be programmed on the Homework board through an RS232 connection, and it's programmed in P-BASIC (there's one on my desk
).
I hope that helps a little.