hwa/atmel/avr/examples/01-1-blink-soft/main.c

Blink a LED using a software loop

This program configures the LED pin as a digital output, then in an infinite loop it toggles the LED state and waits for half the period to be elapsed.

Symbols:

• BOARD_H is the name of the target board definition file. It can be specified at compile time via the command line. If not, the Makefile will set it to attiny84 by default. For example, make BOARD=nanodccduino will lead to BOARD_H defined as <boards/nanodccduino.h>. See Development boards for the list of board definition files provided.
• PIN_LED is the name of the I/O pin at which a LED is connected. It is defined in the target board header file.
• PERIOD is the blinking period.
• HW_SYSHZ is the CPU frequency, computed by HWA from the device configuration fuses.

main.c

 
/*  This file is part of the HWA project.
 *  Copyright (c) 2012,2015 Christophe Duparquet.
 *  All rights reserved. Read LICENSE.TXT for details.
 */
 
#include BOARD_H
 
#define PERIOD                  0.5
 
 
int main ( )
{
  hw( configure, PIN_LED, mode, digital_output );
  
  for(;;) {
    hw( toggle, PIN_LED );
    hw_waste_cycles( PERIOD/2 * HW_SYSHZ );
  }
}