I built a circuit board recently that was designed to have an atmega328 communicate with a SM130 RFID Chip. I’m received my boards and assembled them, but they’re acting very strangely. Whenever I try a program on the commercial UNO board, it works fine. If I remove that microcontroller and plug it into a socket on my board, it doesn’t work at all – even simple sketches like Blink.
I’ve attached an image of my schematic. I checked the following things on my board:
-+5V on VCC, AVCC, AREF, RESET
-GND on pins 8 and 22.
I have an external 16 MHz crystal with 2x 22 pF capacitors.
As far as I can tell, there doesn’t seem to be any shorts, so I’m at a loss as to how to approach this any further. As I said, if I upload the Blink sketch on my UNO Board, I can test Pin 13 (Pin 19 on the microcontroller) to see if I get a square wave – and I do. As soon as I place the Atmega onto the board’s socket, Pin 19 stops outputting a square wave.
Any thoughts on how to move forward? Any general troubleshooting techniques would be greatly appreciated.
side_table.pdf (51.4 KB)