Hi all,
I am currently a first time Arduino user. I decided to get one and start prototyping basic types of circuits.
I have built various basic circuits with the Arduino Uno prototype board and it worked completely fine. However, when I built the attached circuit, everything stopped working.
I don't get output from any of the pins and I cannot upload programs to the board. The yellow LED still blinks, and the green power LED remains green and active. I powered the board through the USB port.
I cannot figure out how I managed to burn the board. The current is around 22.72mA, which is pretty far of the 40mA absolute rating.
OP's image
What happens when you disconnect everything?
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I don't think it applies, but there are a few more limits.
1)
Absolute maximum per pin is 40mA, safe maximum is 20mA per pin.
2)
100mA per port.
3)
200mA through Vcc / Gnd of processor.
Do you happen to connect anything to the RX/TX pins? Doing so will prevent uploading new sketches.
DrDiettrich:
Do you happen to connect anything to the RX/TX pins? Doing so will prevent uploading new sketches.
In beginners speak this translates into are you using pins 0 or 1? If so don’t.
sterretje:
OP's image
What happens when you disconnect everything?
====
I don't think it applies, but there are a few more limits.
1)
Absolute maximum per pin is 40mA, safe maximum is 20mA per pin.
2)
100mA per port.
3)
200mA through Vcc / Gnd of processor.
It still does not work with everything disconnected.
I've discovered that I had incorrectly configured the 7 segment display. I've tried out the same experiment with a correct configuration and a 1K resistor on a new board. It works fine now. Next time, I will learn not to be so hasty.
DrDiettrich:
Do you happen to connect anything to the RX/TX pins? Doing so will prevent uploading new sketches.
Grumpy_Mike:
In beginners speak this translates into are you using pins 0 or 1? If so don’t.
I've tested it out using pins 2 - 13.
However, when I built the attached circuit, everything stopped working.
Sounds like you wired something wrong.
Can you post a photograph of your setup so we can follow the wires.
Grumpy_Mike:
Sounds like you wired something wrong.
See reply #4 
I've discovered that I had incorrectly configured the 7 segment display. I've tried out the same experiment with a correct configuration and a 1K resistor on a new board. It works fine now. Next time, I will learn not to be so hasty.
Grumpy_Mike:
Can you post a photograph of your setup so we can follow the wires.
I think that that is still a good idea; or a proper schematic. One 1k resistor is quite odd in my opinion.