tone.c

嵌入式系统基础课件

#include "libepc.h"
#include "tetris.h"

/* ------------------------------------------------------------ */
/* Play a tone on the speaker for 1/4th of a second.		*/
/* ------------------------------------------------------------ */
void Tone(int hertz)
	{
	DWORD32 timer = Now_Plus(0) + 250 ; /* 0.25 secs */
	Sound(hertz) ;
	while (Now_Plus(0) < timer) ;
	Sound(0) ;
	}