s12_crg.h

source code for a sample alarm control panel system using Freescale MC9S12DP256 . The project was im

//=============================================================================
// File: S12_CRG.H - V1.00
// Rem.: The ACPRD Project Page on the Web -> http://hc12web.de/acprd
//=============================================================================

#ifndef __S12_CRG_H
#define __S12_CRG_H

//-- CRG Bit Mask Definitions -------------------------------------------------

// Bits in CRGFLG:
#define BM_RTIF		0x80
#define BM_PORF		0x40
//#define reserved	0x20
#define BM_LOCKIF	0x10
#define BM_LOCK		0x08
#define BM_TRACK	0x04
#define BM_SCMIF	0x02
#define BM_SCM		0x01

// Bits in CRGINT:
#define BM_RTIE		0x80
//#define reserved	0x40
//#define reserved	0x20
#define BM_LOCKIE	0x10
//#define reserved	0x08
//#define reserved	0x04
#define BM_SCMIE	0x02
//#define reserved	0x01

// Bits in CLKSEL:
#define BM_PLLSEL	0x80
#define BM_PSTP		0x40
#define BM_SYSWAI	0x20
#define BM_ROAWAI	0x10
#define BM_PLLWAI	0x08
#define BM_CWAI		0x04
#define BM_RTIWAI	0x02
#define BM_COPWAI	0x01

// Bits in PLLCTL:
#define BM_CME		0x80
#define BM_PLLON	0x40
#define BM_AUTO		0x20
#define BM_ACQ		0x10
//#define reserved	0x08
#define BM_PRE		0x04
#define BM_PCE		0x02
#define BM_SCME		0x01

//-- Defines ------------------------------------------------------------------

// set the following values according to system requirements:
//
#define S12_OSCCLK	16000000		// input frequency from Xtal/Osc
#define S12_REFCLK	 8000000		// PLL internal reference clock
#define S12_PLLCLK	48000000		// desired output frequency of PLL

// PLL clock generation formula, according to CRG Block User Guide:
// PLLCLK = OSCCLK * 2(SYNR+1) / (REFDV+1)
//
#define S12_REFDV	((S12_OSCCLK/S12_REFCLK)-1)
#define S12_SYNR	((S12_PLLCLK/(2*S12_REFCLK))-1)

#define S12_ECLK	(S12_PLLCLK/2)	// final bus clock frequency (ECLK)
//#define S12_ECLK	(S12_OSCCLK/2)	// bus clock if PLL not in use / off

//-- Function Prototypes ------------------------------------------------------

void initPLL(void);

#endif //__S12_CRG_H ==========================================================