2440beep.c

来自「嵌入式实验代码非常适合全面学习ARMS3C2440,有20多个练习代码」· C语言 代码 · 共 42 行

#include "2440addr.h"
#include "2440lib.h"
#include "def.h"

/****************************************************************************
【功能说明】蜂鸣器PWM测试
****************************************************************************/

void Buzzer_Freq_Set( U32 freq )
{   
    //set GPB1 as TOUT1, pwm output
	rGPBCON = rGPBCON &~(3<<2)|(1<<3);

	rTCFG0 = rTCFG0 &~(0xff)|(15);	
	rTCFG1 = rTCFG1 &~(0xf<<4)|(1<<5);
		
	rTCNTB1 = (PCLK>>7)/freq;
	rTCMPB1 = rTCNTB1>>1;	// 50%
	
	//disable deadzone, auto-reload, inv-off, update TCNTB1&TCMPB1, start timer 1
	rTCON = rTCON &~(0xf<<8)|(0xb<<8);
	rTCON &= ~(1<<9);	//clear manual update bit
}

void Buzzer_Stop( void )
{
	rGPBCON &= ~12;			//set GPB1 as output
	rGPBCON |= 4;
	rGPBDAT &= ~1;
}

void Buzzer_PWM_Run( void )
{
	U16 freq = 2000 ;
	Buzzer_Freq_Set( freq ) ;
}