Standalone ATmega328p not working

Question

I designed a standalone ATmega328p board (like an Arduino Nano). I use an Arduino Nano as an ISP Programmer, I can set the fuse bits and flash the program to it. But the ATmega shows absolutely no signs of life (I built an LED with resistor on pin PB2 and wanted it to make blink).

Tried another pin - not working. No signs of life at all. All the parts except the ISP connector were soldered by the JLCBPCB SMT service.

Here is the schematic:

And here are the pictures of the PCB design:

Top Layer:

Bottom Layer:

Did I make a design error which I'm not seeing or is the chip maybe just broken?

I let JLC assemble two boards and they both behave the same - setting fuse bits and flashing the program - possible. But blinking an LED - No. Absolutely no signs of life.

I personally doubt it, that BOTH chips are broken - as they are brand new.

Has anyone encountered a similar problem? Thanks for your help.

Answer 1

Okay guys, finally found the solution for my problem:

At first I thought the capacitor C1 which is connected between RST and GND, was the problem, so I removed it. But this did not fix the problem.

It was indeed a software problem. I programmed the Mega328P using the Arduino IDE and MiniCore.

It seems like for some reason, the standard Arduino commands "pinMode()", or "digitalWrite()" etc. don't work.

But when I'm using the port register commands with DDRx and PORTx, everything works.

So instead of writing

pinMode(PB2, OUTPUT);
digitalWrite(PB2, HIGH);
delay(1000);
digitalWrite(PB2, LOW);
delay(1000);

I wrote

DDRB |= (1<<PB2);
PORTB |= (1<<PB2);
delay(1000);
PORTB &= ~(1<<PB2);
delay(1000);

and that solved my problem.

Why didn't I think of that earlier?

Edit: what also works, is instead of

digitalWrite(PB2, HIGH);

writing

digitalWrite(PIN_PB2, HIGH);