?? delay.h
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#ifndef _delay_h_#define _delay_h_#include <inttypes.h>#include <avr/io.h>#ifndef F_OSC#define F_OSC 3686400#endif/* 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
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