osc.c

采用四端法测试欧姆电阻

#ifndef _OSC_C_
#define _OSC_C_



#include <c8051f000.h>  
#include "osc.h"

//-----------------------------------------------------------------------------
// F0xx_Osc_Init.c
//-----------------------------------------------------------------------------
// Copyright 2003 Cygnal Integrated Products, Inc.
//
// AUTH: FB
// DATE: 27 DEC 02
//
// This program shows an example of configuring the internal  
// and external oscillators. 
//
// Target: C8051F00x and C8051F01x
// Tool chain: KEIL C51 6.03 / KEIL EVAL C51
//



//-----------------------------------------------------------------------------
// Initialization Subroutines
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// fSYSCLK_IntOsc_Init
//-----------------------------------------------------------------------------
//
// This routine initializes the system clock to use the internal oscillator
// at its maximum frequency.
//
void fSYSCLK_IntOsc_Init (void)
{
   OSCICN = 0x87;                      // Set internal oscillator to 
                                       // maximum frequency and enable missing
                                       // clock detector
}

//-----------------------------------------------------------------------------
// fSYSCLK_Crystal_Init
//-----------------------------------------------------------------------------
//
// This routine initializes the system clock to use a 22.1184MHz crystal
// as its clock source. Assumes a 22.1184 MHz crystal and associated loading
// capacitors are connected at XTAL1 and XTAL2.
//
void fSYSCLK_Crystal_Init (void)
{
   int i;                              // delay counter

   OSCXCN = 0x67;                      // start external oscillator with
                                       // 22.1184MHz crystal

   for (i=0; i < 256; i++) ;           // XTLVLD blanking interval (>1ms)

   while (!(OSCXCN & 0x80)) ;          // Wait for crystal osc. to settle

   OSCICN = 0x88;                      // select external oscillator as SYSCLK
                                       // source and enable missing clock
                                       // detector
}

//-----------------------------------------------------------------------------
// fSYSCLK_C_RC_Init
//-----------------------------------------------------------------------------
//
// This routine initializes the system clock to use an external RC network
// or a single capacitor as its clock source. Assumes an RC network is  
// connected to XTAL1 or a single capacitor is connected to XTAL1 and
// XTAL2.
//
void fSYSCLK_C_RC_Init (void)
{
   OSCXCN = 0x47;                      // start external oscillator in
                                       // C/RC mode with XFCN = 7

   OSCICN = 0x88;                      // select external oscillator as SYSCLK
                                       // source and enable missing clock
                                       // detector
}

//-----------------------------------------------------------------------------
// fSYSCLK_CMOS_Init
//-----------------------------------------------------------------------------
//
// This routine initializes the system clock to the external oscillator in
// CMOS clock mode. Assumes a CMOS clock generator is connected to XTAL1.
//
void fSYSCLK_CMOS_Init (void)
{
   OSCXCN = 0x20;                      // start external oscillator in 
                                       // CMOS clock mode.
   
   OSCICN = 0x88;                      // select external oscillator as SYSCLK
                                       // source and enable missing clock
                                       // detector
}

#endif