Basic question: What's the basic circuit I need to create to run an ATMega8515?
I'm (obviously) new to this but very excited about plans to use an AVR to control a ball throwing machine I'm building. Eventually I plan to control two motors with PWM and probably a couple more stepper motors to aim the thing. I also hope to sense the PWM control motors' speed.
But, I'm stumbling with the very basics. I've got a decent programming background, but the electronics are all new. I've found David Cook's robot building books VERY helpful for motor control circuits and some basics on electronics.
I've just recently gotten an STK500 which comes with a ATMega8515L pre-programmed with a simple LED flashing program. What I wanted to do was run that same ATMega8515 on a breadboard as a small step towards building my own circuits. But I can't get it to work.
Here's what I thought would work:
5+V to Pin40 (Vcc)
Ground to Pin20 (GND)
One LED with 470ohm R between Pin1 (PB0) and ground
(in the test program PortB is output for all bits, but I'm just trying to get one to work)
Then I tried using a jumper from 5+V to touch Pins 10-16 (PD0-6) as inputs.
But that LED on PB0 isn't flashing on and off as I expected. I've tried several variations like reversing the LED (in case it was backwards) and connecting the LED on the output pin to 5+V, and other potentially dumb things.
As you can tell, I'm relying on the internal oscillator and I've left XTAL1 and XTAL2 discounnected as that's what I read in the datasheet. But I'm suspicious about that.
Any suggestions GREATLY appreciated.