stm8时钟切换机制

zhaxiaoxi

[mw_shl_code=c,true]

[mw_shl_code=c,true]/* MAIN.C file * * Copyright (c) 2002-2005 STMicroelectronics */ /*程序描述：切换时钟源*/ #include"stm8s105s4.h" //函数功能：延时功能 //输入参数：ms--要延时的毫秒数，这里假设cpu的主频为2M //输出参数：无 //返回参数：无 //备 注: 无 void DelayMs(unsigned int ms) { while(ms != 0) { unsigned char i; for(i=0;i<250;i++); for(i=0;i<75;i++); ms--; } } void GPIO_Int(void) { PD_DDR = 0X18; PD_CR1 = 0X18; PD_CR2 = 0X00; } _Bool led2 @PD_ODR:3; _Bool led1 @PD_ODR:4; main() { int i; GPIO_Int(); CLK_ECKR = 0X01;//enable HSE while((CLK_ECKR & 0x02) == 0x00);//等待HSE for(;;) { CLK_SWCR = CLK_SWCR | 0x02;//enable switch CLK_SWR = 0xB4;//set hse as master clock while((CLK_SWCR & 0x08) == 0);//judge hse ready or not CLK_SWCR = CLK_SWCR & 0xFD;//clear sign for(i=0;i<10;i++) { led2 = 1; led1 = 1; DelayMs(100); led2 = 0; led1 = 0; DelayMs(100); } CLK_SWR = 0xE1; while((CLK_SWCR & 0x08) == 0); CLK_SWCR = CLK_SWCR | 0x02; CLK_SWCR = CLK_SWCR & 0xFD; for(i=0;i<10;i++) { led2 = 1; led1 = 1; DelayMs(100); led2 = 0; led2 = 0; DelayMs(100); } } } [/mw_shl_code]

[/mw_shl_code]

为什么我烧录进去之后没有看到任何现象只能看到两个led小灯长亮？

本人新手，感谢高手解答。

正点原子

帮顶.....