STM32F103配置系统时钟的代码【寄存器篇】

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Dylan疾风闪电发布时间：2018-8-9 14:12

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本帖最后由 Dylan疾风闪电于 2018-8-9 15:39 编辑

使用举例：配置72MHZ时钟作为系统时钟#define SystemClockMHz 72//MHZ
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HW_SystemClockMux(USE_EXTERNAL_HSE, SystemClockMHz) ;
HW_SystemClockMux(USE_INTERNAL_HSI, SystemClockMHz);

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代码已验证。发个帖子，便于自己移植使用。

/* Const to source of high speed clock:internal or external. */1 T9 G# b( O7 v* l3 q& n7 T0 H" e
#define USE_EXTERNAL_HSE 0
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#define USE_INTERNAL_HSI 1
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/**
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* 配製系統主時鐘頻率。 _$ \$ E( f. L' H( `% E
* 功能：選擇時鐘源，并進行PLL倍頻。
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* @param osc 高速時鐘源的選擇。
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* @arg USE_EXTERNAL_HSE: 外部高速晶振
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* @arg USE_INTERNAL_HSI: 內部高速晶振
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* @param maxFreq 芯片最大主频？M，查询对应的数据手册
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* @return osc
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* @version 2.0.0.0(20160407)1 ^. ~: ~/ Z/ u$ L
* <p-2014>实现CM0与CM3兼容完成！% H. ?! i* t8 r" Z6 b, z- ^ `
* <p-2016>對字符串/單詞進行變更。
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* @author Dylan
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*/! a5 Z2 e( l d( I! }
uint8_t HW_SystemClockMux(uint8_t osc, uint8_t maxFreq)* L$ L9 E5 Y' O+ h1 q
{
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#if defined (STM32F100) || defined (STM32F101) || defined (STM32F103)
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uint8_t errCode = 0xff;
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uint32_t sTimeCount, sTimeMax = 0xFFF;% F6 d& r4 J7 {& e' ]% Y5 N
#endif% |7 u0 W5 H& j" Z' F p5 ]
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HW_SystemPowerON(); T1 `% p) q; X% V$ q% X
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switch(osc)
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{
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case USE_EXTERNAL_HSE:6 I, E( |7 _, r5 A
#if defined (STM32F100) || defined (STM32F101) || defined (STM32F103)
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RCC->CR |= 1<<16; //HSEON
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sTimeCount = sTimeMax;- e# u, I4 [1 y$ P2 q. k
while(((RCC->CR>>17) & 0x1) == 0) //等待HSE就绪- [/ F' i# V$ k* }( S/ J
{
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if (sTimeCount--) return errCode;* k+ R' Q8 i/ h' x$ @* B
}
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RCC->CFGR |= (maxFreq/8-2)<<18; //设置PLL值倍频//HSE 8MHz* u7 u7 Z' I3 a2 M4 k0 S
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RCC->CFGR |= 1<<16; //切换PLL输入时钟源为0->1：HSI/2(4MHz)->HSE(8MHz)
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//存在等待状态时，必须先开启预取缓冲区
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if (maxFreq <= 24)
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FLASH->ACR |= 0x30;//000：零等待状态，当 0 < SYSCLK ≤ 24MHz
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else if (maxFreq <= 48)
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FLASH->ACR |= 0x31;//001：一个等待状态，当 24MHz < SYSCLK ≤ 48MHz
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else
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FLASH->ACR |= 0x32;//010：两个等待状态，当 48MHz < SYSCLK ≤ 72MHz
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RCC->CR |= 1<<24; //PLLON" j \1 k: n5 _ ~
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sTimeCount = sTimeMax;
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while(((RCC->CR>>25) & 0x1) == 0) //等待PLL就绪. F8 S2 w) I' w- q- ]; w) F
{
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if (sTimeCount--) return errCode;
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RCC->CFGR |= 0x2; //PLL作为sysClk: g" b; i5 Y- g c7 k l4 K
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sTimeCount = sTimeMax;2 @1 d, j, X7 U+ j+ s1 d
while(((RCC->CFGR>>2) & 0x3) != 0x02) //等待sysClk就绪 v8 i( ]6 g$ b( k3 M3 R, c( V
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if (sTimeCount--) return errCode; X! _' X( v, D6 v: Q
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#elif defined (STM32F051) || defined (STM32F042) //none7 ?6 u, K& o, O! b; O1 }6 Z' O
#else
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#warning "Make sure needn't define STM32Fxxx etc. ?"
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#endif
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break;2 ^5 D! J9 ?6 f
default: //case USE_INTERNAL_HSI:1 T* T% J- Q. H) @
RCC->CFGR &= 0xFFFEFFFF; //HSI 8MHz/24 o$ X( F& d; `% g/ w1 x
RCC->CFGR |= ((maxFreq>>2)-2)<<18; //设置PLL值倍频
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//存在等待状态时，必须先开启预取缓冲区, j! {2 \3 ^! b7 N9 L6 d
if (maxFreq <= 24)
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FLASH->ACR |= 0x30;//000：零等待状态，当 0 < SYSCLK ≤ 24MHz
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else if (maxFreq <= 48)2 h1 D2 z: t4 V/ V% o8 L
FLASH->ACR |= 0x31;//001：一个等待状态，当 24MHz < SYSCLK ≤ 48MHz, Y- r0 B d& \$ z; U* f
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FLASH->ACR |= 0x32;//010：两个等待状态，当 48MHz < SYSCLK ≤ 72MHz9 Q; i m1 M3 V$ V' x
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RCC->CR |= 1<<24; //PLLON1 B, n3 h# b0 R$ K+ O
while(((RCC->CR>>25) & 0x1) != 1); //等待PLL就绪
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RCC->CFGR |= 0x2; //PLL作为sysClk; t; E: r7 `( g3 w
while(((RCC->CFGR>>2)&0x3) != 0x02); //等待sysClk就绪
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break;0 D" K" @1 ^; E2 M+ P
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return 0;2 x: l: X: ^' n% F' `
}
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/**. l3 @' ~6 H/ @* c: I9 N
* 芯片上电默认时钟配置。# z' B) \; Y5 P) x
* 功能：用来恢复时钟系统到上电默认状态。- I$ l. @& V2 n4 p' b* v
* @version 1.1.0.0(20140228)) X5 h/ i4 O. n3 l. E* d& X
* <p-2014>实现CM0与CM3兼容完成！% c- f. }% l) e9 L5 N
* @author Dylan
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void HW_SystemPowerON(void)' n. H& F. d& g5 b6 \
{
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#if defined (STM32F051) || defined (STM32F042)) Y/ M5 A/ R/ B, ]1 v# ?& y0 A
RCC->CR |= 0x00000001;//HSION
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RCC->CR &= 0x0202FFFF;/* Reset HSEON, CSSON and PLLON, HSEBYP bit *// A/ ^* w& X ~# ~
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RCC->CFGR &= 0x0000000C;/* Reset SW[1:0], HPRE[3:0], PPRE[2:0], ADCPRE and MCOSEL[2:0],PLLSRC, PLLXTPRE and PLLMUL[3:0] bits */
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RCC->CFGR2 &= 0x00000000;/* Reset PREDIV1[3:0] bits *///与CFGR[17]一起用作HSE-PLL设置
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RCC->CFGR3 &= 0x00000000;/* Reset USARTSW[1:0], I2CSW, CECSW and ADCSW bits */8 u8 |1 i% [, w9 i
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RCC->CR2 &= 0xFFFFFFFE;/* Reset HSI14 bit */5 n. ~4 E7 c; S# N% L" m2 q
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RCC->CIR = 0x00000000;/* Disable all interrupts */
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#elif defined (STM32F100) || defined (STM32F101) || defined (STM32F103)
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RCC->CR &= 0x0000FF83;//把HSI调整到8MHz±1%==》开启HSI==》等待就绪6 V4 U" H1 |+ e# {5 {8 Y
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RCC->CFGR = 0x00000400;//限制APB1时钟是HCLK_Div2! t/ y* l2 m* B: u" h3 F
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RCC->CIR = 0x00BF0000;//清除所有的RCC中断标志; z f3 W8 ^5 ~
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//配置向量表* a* `: s; R3 d' v
#ifdef VECT_TAB_RAM
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/* Set the Vector Table base location at 0x20000000 */. r. T X j3 l* H3 S5 _, Y3 a7 ~ N
NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);
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#else /* VECT_TAB_FLASH */6 x: e W: ?9 M. D! [
/* Set the Vector Table base location at 0x08000000 */
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NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);
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#endif7 x* }2 V0 d% P& b; ^
#else" g! U, U6 V1 T* s0 v' l ^
#warning "Make sure needn't define STM32F051 etc. ?"
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#endif
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}