将系统时钟初始化到72MHz的函数
根据数据手册和库函数，设置STM32时钟为72MHz
- 这是.c文件
#include "clock.h"
void Set_SysClockTo72M(void)
{
unsigned int faultTime = 0;
unsigned int rccCrHserdy = 0;
unsigned int rccCrPLLrdy = 0;
rRCC_CR = RCC_CR_RESET;
rRCC_CR &= ~(1<<16);
rRCC_CR |= (1<<16);
do
{
rccCrHserdy = rRCC_CR & (1<<17);
faultTime++;
}
while ((faultTime<0x0FFFFFFF) && (rccCrHserdy==0));
if ((rRCC_CR & (1<<17)) != 0)
{
rFLASH_ACR |= 0x10;
rFLASH_ACR &= (~0x03);
rFLASH_ACR |= 0x02;
rRCC_CFGR &= (~((0x0F<<4) | (0x07<<8) | (0x07<<11)));
rRCC_CFGR |= ((0x0<<4) | (0x04<<8) | (0x0<<11));
rRCC_CFGR &= (~((0x01<<16) | (0x1<<17)));
rRCC_CFGR |= ((0x01<<16) | (0x0<<17));
rRCC_CFGR &= (~(0x0f<<18));
rRCC_CFGR |= (0x07<<18);
rRCC_CR |= (0x01<<24);
faultTime = 0;
do
{
rccCrPLLrdy = rRCC_CR & (1<<25);
faultTime++;
}
while ((faultTime<0x0FFFFFFF) && (rccCrPLLrdy==0));
if ((rRCC_CR & (1<<25)) == (1<<25))
{
rRCC_CFGR &= (~(0x03<<0));
rRCC_CFGR |= (0x02<<0);
faultTime = 0;
do
{
rccCrPLLrdy = rRCC_CFGR & (0x03<<2);
faultTime++;
}
while ((faultTime<0x0FFFFFFF) && (rccCrPLLrdy!=(0x02<<2)));
if(rRCC_CFGR & (0x03<<2))
{
}
else
{
while(1);
}
}
else
{
while(1);
}
}
else
{
while(1);
}
}
- 这是.h文件
#ifndef __CLOCK_H__
#define __CLOCK_H__
#define FLASH_ACR 0x40022000
#define RCC_BASE 0x40021000
#define RCC_CR (RCC_BASE + 0x00)
#define RCC_CFGR (RCC_BASE + 0x04)
#define rRCC_CR (*((volatile unsigned int *)RCC_CR))
#define rRCC_CFGR (*((volatile unsigned int *)RCC_CFGR))
#define rFLASH_ACR (*((volatile unsigned int *)FLASH_ACR))
#define RCC_CR_RESET (0x00000083)
void Set_SysClockTo72M(void);
#endif
（为什么无法正常显示keil文件的中文注释…）
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