2440beep.c

嵌入式实验代码非常适合全面学习ARMS3C2440,有20多个练习代码

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

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

void xmain(void)
{
	ChangeClockDivider(3,1);//1:3:6
	ChangeMPllValue(127,2,1);		//405MHZ
	Port_Init();
	Isr_Init();
	Uart_Init(0, 115200);
	Uart_Select(0);
	Uart_Printf("the main is running\n");
	
	BUZZER_PWM_Test();
	
}

/****************************************************************************
【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_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 += 100 ;
				
			Buzzer_Freq_Set( freq ) ;
		}

		if( key == '-' )
		{
			if( freq > 100 )
				freq -= 100 ;
				
			Buzzer_Freq_Set( freq ) ;
		}
		
		Uart_Printf( "\tFreq = %d\n", freq ) ;
		if( key == ESC_KEY )
		{
			Buzzer_Stop() ;
			return ;
		}

	}

}