#ifndef _delay_h_
#define _delay_h_
#include <inttypes.h>
#include <avr/io.h>
/* For compatibility with bios. If standalone app comment these two lines */
#include <bios.h>
#define F_OSC F_CPU
/* delay function for microsec
4 cpu cycles per loop + 1 cycles(?) overhead
when a constant is passed. */
static inline void delayloop16(uint16_t count)
{
asm volatile ( "cp %A0,__zero_reg__ \n\t" \
"cpc %B0,__zero_reg__ \n\t" \
"breq L_Exit_%= \n\t" \
"L_LOOP_%=: \n\t" \
"sbiw %0,1 \n\t" \
"brne L_LOOP_%= \n\t" \
"L_Exit_%=: \n\t" \
: "=w" (count)
: "0" (count)
);
}
// delayloop16(x) eats 4 cycles per x
#define DELAY_US_CONV(us) ((uint16_t)(((((us)*1000L)/(1000000000/F_OSC))-1)/4))
#define delay_us(us) delayloop16(DELAY_US_CONV(us))
/* delay function for millisec
(6 cycles per x + 20(?) overhead) */
void delayloop32( uint32_t l); // not inline
#define DELAY_MS_CONV(ms) ( (uint32_t) (ms*(F_OSC/6000L)) )
#define delay_ms(ms) delayloop32(DELAY_MS_CONV(ms))
/* mth 9/04:
Remark uSeconds:
Main Oscillator Clock given by F_OSC (makefile) in Hz
one CPU-Cycle takes 1/F_OSC seconds => 1000000/F_OSC uSeconds
so: 1 uSecond takes F_OSC/1000000 CPU-Cyles. The following code
is inspired by the avr-libc delay_loop2 function.
This it not "that precise" since it takes at least 4 cycles
but should be o.k. with any parameter (even 0).
Call function with delayloop(DELAYUS(dt [in uSeconds])).
*/
#endif