2410beep.c

S3C2410学习的基础资料 大部分实验源码及工程

#include "2410addr.h"
#include "2410lib.h"
#include "def.h"

void Buzzer_Freq_Set( U32 freq );
void Buzzer_Stop( void );
void BUZZER_PWM_Test( void );

void xmain(void)
{
	ChangeClockDivider(1, 1);
	ChangeMPllValue(0xa1,0x3,0x1);
   
	Port_Init();
		
	Uart_Select(0);
	Uart_Init(0, 115200);
	BUZZER_PWM_Test();
	
	while(1);
}

/****************************************************************************
【功能说明】蜂鸣器PWM测试
****************************************************************************/
void BUZZER_PWM_Test( void )
{
	U16 freq = 2000 ;
	
	Uart_Printf( "\nBUZZER TEST ( PWM Control )\n" );
   	Uart_Printf( "Press +/- to increase/reduce the frequency of BUZZER !\n" ) ;
	Uart_Printf( "Press 'ESC' key to Exit this program !\n\n" );
	
	Buzzer_Freq_Set( freq ) ;

    while( 1 )
    {
		U8 key = Uart_Getch();

		if( key == '+' )
		{
			if( freq < 20000 )
				freq += 10 ;
				
			Buzzer_Freq_Set( freq ) ;
		}

		if( key == '-' )
		{
			if( freq > 11 )
				freq -= 10 ;
				
			Buzzer_Freq_Set( freq ) ;
		}
		
		Uart_Printf( "\tFreq = %d\n", freq ) ;
		if( key == ESC_KEY )
		{
			Buzzer_Stop() ;
			return ;
		}
	}
}

void Buzzer_Freq_Set( U32 freq )
{
	rGPBCON = rGPBCON & ~(3<<0)|(1<<1);//set GPB0 as tout0, pwm output
		
	rTCFG0 = rTCFG0 & ~0xff|15; //prescaler = 15
	rTCFG1 = rTCFG1 & ~0xf|2;//divider = 1/8
			
	rTCNTB0 = (PCLK>>7)/freq;//rTCNTB0=PCLK/{(prescaler+1) * divider *freq}
	rTCMPB0 = rTCNTB0>>1;	//占空比50%
	
	//disable deadzone, auto-reload, inv-off, update TCNTB0&TCMPB0, start timer 0
	rTCON = rTCON & ~0x1f|(0<<4)|(1<<3)|(0<<2)|(1<<1)|(1);
	rTCON &= ~(1<<1);			//clear manual update bit
}

void Buzzer_Stop( void )
{
	rGPBCON |= 1;
		
	rGPBCON = rGPBCON & ~3|1;			//set GPB0 as output
	rGPBDAT &= ~1;//output 0
}