Re: [avr-chat] sample code for ATmega48?

[Matthew MacClary]

On 5/31/07, address@hidden <address@hidden> wrote:
> A good test program would be something that, say, sets all output pins
> of the chip to high for 3 seconds, then low for 3 seconds, and repeats.

Here is some code, I haven't tried it on an Atmega48 yet though. Here
are the compile commands:

$ avr-gcc -g -Wall -pedantic -Os    -mmcu=atmega48    -c -o main.o main.c
$ avr-gcc -I  -g -Wall -pedantic -Os    -mmcu=atmega48
-Wl,-Map,main.map -o main.elf main.o
$ avr-objcopy -j .text -j .data -O ihex main.elf main.hex

/* This program flashes all of the I/O pins on the Atmega48 on and off
  with a 3 second delay. */

#include <avr/io.h>

#undef F_CPU
#define F_CPU 20000000UL /* 20MHz */

#include <util/delay.h>

void delay_ms(uint32_t time) {
 uint32_t i;
 for (i = 0; i < time; i++) {
   _delay_ms(1);
 }
}

int main() {
 /* Set ports to outputs */
 DDRB = 0xff;
 DDRC = 0x7f; /* PORTC has only 7 pins */
 DDRD = 0xff;

 while (1) {
   PORTB ^= 0xff;
   PORTC ^= 0x7f;
   PORTD ^= 0xff;
   delay_ms(3000);
 }

 return 0;
}

main.hex
Description: Binary data