I followed guide at Arduino - Setting up an Arduino on a breadboard First i created the power circuit and tested voltages, working good, even 5 volts. After taking a led blink loaded atmega328pu from my uno r3 and hooking up to breadboard and setting up the rest of the circuit nothing works and the voltages are all wonky. Please help. I’m rather noobish and not sure whats wrong, i triple checked and still cannot figure it out, is there something i’m missing?
Could you be more specific than "voltages are all wonky"?
If the regulator output is still a solid 5V then the problem is probably between the regulator and the chip. If the regulator output is dropping there could be a short circuit somewhere.
Breadboards often develop bad connections. Perhaps there is a bad connection in the power circuits. Disconnect from power and check the resistance from the regulator to the far end of the power rails.
Add a 0.1 uF decoupling capacitor on both sides, between VCC and Gnd, and AVCC and Gnd.
This is a better guide: http://www.gammon.com.au/breadboard
Thank you for your suggestions. I added the .1 pf capacitors and found that if i remove the jumper wire from "Pin 21 - AREF - Analog reference pin for ADC" that everything works. What is this particular pins purpose? Why do the directions include this? If you can explain I would appreciate it.
Can someone please explain the ADC AREF pin issue to me I don't know what it is for and why it disables my chip when hooked up to the 5v rail.
It is connected internally thru a mux - when you connect 5V to it can damage the mux depending on the settings selected.
Bottom line - don't connect Aref to 5V externally, that is already one of the internal selections you can make.