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RIOT/examples/blinky/main.c

63 lines
1.5 KiB
C

/*
* Copyright (C) 2021 Otto-von-Guericke-Universität Magdeburg
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup examples
* @{
*
* @file
* @brief Blinky application
*
* @author Marian Buschsieweke <marian.buschsieweke@ovgu.de>
*
* @}
*/
#include <stdio.h>
#include "clk.h"
#include "board.h"
#include "periph_conf.h"
#include "timex.h"
#include "ztimer.h"
static void delay(void)
{
if (IS_USED(MODULE_ZTIMER)) {
ztimer_sleep(ZTIMER_USEC, 1 * US_PER_SEC);
}
else {
/*
* As fallback for freshly ported boards with no timer drivers written
* yet, we just use the CPU to delay execution and assume that roughly
* 20 CPU cycles are spend per loop iteration.
*
* Note that the volatile qualifier disables compiler optimizations for
* all accesses to the counter variable. Without volatile, modern
* compilers would detect that the loop is only wasting CPU cycles and
* optimize it out - but here the wasting of CPU cycles is desired.
*/
uint32_t loops = coreclk() / 20;
for (volatile uint32_t i = 0; i < loops; i++) { }
}
}
int main(void)
{
while (1) {
delay();
#ifdef LED0_TOGGLE
LED0_TOGGLE;
#else
puts("Blink! (No LED present or configured...)");
#endif
}
return 0;
}