Hi! I'm a programmer (x86/64 C/C++ etc) professionally, but as a hobby I've started dabbling with electronics. I have successfully assembled and interfaced USBTinyISP from Adafruit (http://learn.adafruit.com/usbtinyisp) with my computer and flashed an ATTiny 2313 controller with small LED flashing program with AVRDude.
The circuit is the simple LED flasher (http://learn.adafruit.com/usbtinyisp) consisting of 330 ohm resistor and a LED attached to pin corresponding to PD6 register. The program is also taken from the same page. I tried out different modifications of the program and it appears that changing the output pin and setting it to high or low works at the start of the program, but it seems to only happen once. IE, I can delay for 200ms and turn the LED on after that, but it won't turn off again.
My only guess is that the power-supply is faulty and provides unstable voltage. I am using a power-supply salvaged from old 90 MHz Pentium computer. Using multi-meter the power-supply seems to fluctuate at around 5.1-5.25 volts. It also makes suspicious sound each second or so and the brightness of enabled LED seems to fluctuate at the same frequency. Could this be the problem and should I try to find another power-source or is there something else that might be amiss that I should try first? I would try swapping the power-supply at once, but I don't have another one at hand and it might be a while until I can replace it...
Thank you in advance,
Janice
The circuit is the simple LED flasher (http://learn.adafruit.com/usbtinyisp) consisting of 330 ohm resistor and a LED attached to pin corresponding to PD6 register. The program is also taken from the same page. I tried out different modifications of the program and it appears that changing the output pin and setting it to high or low works at the start of the program, but it seems to only happen once. IE, I can delay for 200ms and turn the LED on after that, but it won't turn off again.
My only guess is that the power-supply is faulty and provides unstable voltage. I am using a power-supply salvaged from old 90 MHz Pentium computer. Using multi-meter the power-supply seems to fluctuate at around 5.1-5.25 volts. It also makes suspicious sound each second or so and the brightness of enabled LED seems to fluctuate at the same frequency. Could this be the problem and should I try to find another power-source or is there something else that might be amiss that I should try first? I would try swapping the power-supply at once, but I don't have another one at hand and it might be a while until I can replace it...
Thank you in advance,
Janice