Getting meaningless traces on atmega328p target


#1

Hi, I am working on running basic tutorials on my atmega328p(which is sitting on my arduino uno), but I keep getting meaningless traces.
I did tutorial B2 as a sanity check, but it seems to be failing to read even that.
A screenshot of my settings and trace: imgur.com/a/nDnVQ

I’m supplying a 16MHz clock signal from the output pin 8 of the arduino(which can be set via fuses), and a trigger from pin 7 that I included in the code.
Here’s a picture of my setup: imgur.com/a/WYyDc
Closeup of the shunt resistor: imgur.com/a/VDPrE

I’ve been stuck with this problem for almost a week now. Help would be greatly appreciated T_T


#2

Hi OrigamiGamer,

Based on your picture, I believe your issue is that you don’t have your shunt resistor in series between Vcc in (at the bottom of the socket) and Vcc of the ATMega328P (or the equivalent of with the 328P GND pin and the GND of the the Arduino), as we need to measure the voltage drop over the resistor. It’s probably a little hard to see in the paper you were linked earlier (newae.com/files/OFLYNN_WhitePaper.pdf, page 34), but I’m guessing Vcc isn’t connected straight through and is instead running from through the resistor to another Vcc (maybe from the AVcc pin).

Also, it looks like you’re shorting your shunt resistor, as both ends of the red jumper wire appear to be connected.

Let me know if that helps.

Alex