clock_query.h

来自「BlackFin与摄像头的接口程序」· C头文件 代码 · 共 54 行

/**
 * @file clock_query.h
 * @author Zlatan Stanojevic
 * 
 * @note Define CLKIN before including this header. Otherwise a CLKIN of 25MHz is assumed.
 */


#ifndef CLOCKING_H
#define CLOCKING_H


#ifndef CLKIN
#define CLKIN 25000000
#endif


/**
 * Queries the Core Clock.
 * @return Core Clock in Hz.
 */
inline unsigned long queryCoreClock( void )
{
	unsigned long vco;
	
	vco = *pPLL_CTL >> 9;
	if( ! vco ) vco = 64;
	vco *= CLKIN;
	if( *pPLL_CTL & 0x0001 ) vco /= 2;
	
	return vco * ( 1 << ( *pPLL_DIV >> 4 ) );
}



/**
 * Queries the System Clock
 * @return System Clock in Hz.
 */
inline unsigned long querySystemClock( void )
{
	unsigned long vco;
	
	vco = *pPLL_CTL >> 9;
	if( ! vco ) vco = 64;
	vco *= CLKIN;
	if( *pPLL_CTL & 0x0001 ) vco /= 2;
	
	return vco / ( *pPLL_DIV & 0x000f );
}


#endif