mega2560 standalone problem

Other Hardware 3rd Party Boards
1

Hello

I've done a project on arduino mega 2560 and want to move it to a pcb that i've designed and had manufactured. I've soldered everything together and uploaded the blink sketch using usbasp (i have a led on digital pin 4). It run very slowly. After searching with google, i've learned that i need to set the fuse bites to use the externel crystal (it's a brand new atmega 2560). So i've burned the bootloader (it's supposed to set those bytes). Now the blink sketch will upload but won't do anything, but when i upload:

#ifndef F_CPU
#define F_CPU 16000000UL
#endif

#include <avr/io.h>
#include <util/delay.h>

int main(void)
{
DDRG = (1<<PG5);

while(1)
{
//LED On
PORTG = (1<<PG5);
_delay_ms(1000);

//LED Off
PORTG = (0<<PG5);
_delay_ms(1000);
}
}

it runs ok. Can anyone help me? How to solve this problem?

2

Is the blink sketch assuming the correct pin for the LED? On the official board, it's on PB7, and blink uses that. In the code you showed above, it's on PG5.

3

The led is connected to PG5 witch is digital pin 4 on arduino. Before burning the bootloader/ setting the fuse bits the blink sketch (set to digital pin 4) worked, but slowly. From what i found through google it was running on the internal oscilator set to 1 MHz.

4

I've just solved the problem.

I set the fuses with avrdude, chose settings with a fuse bits calculator:

In my case (16 MHz crystal) the complete command was:

avrdude -c usbasp -p m2560 -U lfuse:w:0xFF:m -U hfuse:w:0xD9:m -U efuse:w:0xFF:m -U lock:w:0xFF:m