I finally got my Wiring board form Sparkfun! Wiring
is a platform similar to the Arduino but using an AVR atmega128 chip. This chip is clocked at 16Mhz while the Arduino is clocked at 20Mhz. The advantage of the 128 is the increased RAM, ROM & Flash capacity over the Arduino. Both share the same development environment and code written for one can be made to run on the other. A 'mini
' version of the board is due out on March 5th and should fit easily inside a Park Flyer sized UAV.
I got the drivers, plugged it in and got it to accept some code. Then I did a little hello world program and I had it flash the on board LED. So far so good, this is pretty cool. Time to break out the RC gear for a more UAV related hello world.
This is a pic of the board and the gear. I have an AR6000, a little 10A Hyperion ESC and a 2S 300mAh lipoly battery. The funny gold thing bridging from the Rx to the board is a tree of female servo connectors. I'm going to make some test jumpers with those.
I tried to read the input from a servo pulse pin and have the LED flash in time with it. First result was a bright glowing LED which didn't seam right. The signal should be off 95% of the time. Further experimentation seem to indicate that the Spektrum Rx I'm using holds the voltage on the signal pin "high" most of the time and only brings it low for the pulse. This is the exact opposite of what I expected! Is this also true of the Futaba gear?
The board is pretty neat and its already teaching me things about my radio gear I didn't know. When I get more time I'll see if I can read the uSec time of a servo pulse using interrupts.