I would like to use my Arduino NG as more of a development environment, and once programmed, move the Atmega8 chip off onto a standalone circuit. I'm pretty sure this is possible, but I'm having troubles. I'm using only digital I/O in my sketch. On the standalone circuit I've hooked up the 2 power and 2 ground pins appropriately, connected a 16 MHz crystal with the appropriate caps to ground (22 pf), and the I/O pins I'm using. (Note, pin mappings were taken from the pin map diagram on the Arduino web site.)
Does anyone know if there are any other caveats when moving from the actual Arduino board to a standalone Atmega8 circuit? Am I missing any pins or whatnot? Right now when I power up the standalone board it does not appear to be working.
The answer to this may be obvious. If so, pardon my noobish-ness. I'm still pretty new to all of this.
I have been able to make two standalone Atmega8 boards myself using instructions on the site. The only thing that was a little scary was the fact that the schematic they give has mistakes on it, but at least they describe the mistakes pretty well. Is it possible for you to post a schematic of what you built? I have been lucky so far... both my boards work perfectly, and I have been able to program the bootloader using the home-made parallel port cable, and then program sketches using a home-made serial cable.
you need the reset pin too, which you don't mention:
pin 1: to +5V through 10K, with reset switch to ground if desired. You can leave out the resistor if you don't use the switch.
pins 9, 10: to crystal with capacitors
pins 7,20: to +5 regulated
pins 8,22: to GND.
The reset pin was it. Once I powered that, everything worked fine. I am powering one of the HC4LED 4-digit displays from Spark Fun, and without the Atmega8 reset pin having power, the display flickered madly and displayed garbage.
Thanks to you both for the help!