init

arduino/led.c

+#include <avr/io.h>
+#include <util/delay.h>
+ 
+#define BLINK_DELAY_MS 1000
+ 
+int main (void)
+{
+ /* set pin 5 of PORTB for output*/
+ DDRB |= _BV(DDB5);
+ 
+ while(1) {
+  /* set pin 5 high to turn led on */
+  PORTB |= _BV(PORTB5);
+  _delay_ms(BLINK_DELAY_MS);
+ 
+  /* set pin 5 low to turn led off */
+  PORTB &= ~_BV(PORTB5);
+  _delay_ms(BLINK_DELAY_MS);
+ }
+}

arduino/led.sh

+avr-gcc -Os -DF_CPU=16000000UL -mmcu=atmega328p -c -o led.o led.c
+avr-gcc -mmcu=atmega328p led.o -o led
+avr-objcopy -O ihex -R .eeprom led led.hex
+avrdude -F -V -c arduino -p ATMEGA328P -P /dev/ttyACM0 -b 115200 -U flash:w:led.hex
+