startup_stm32f10x_md.s文件中,调用了一个叫SystemInit的函数,该函数其实在system_stm32f10x.c中定义,旨在初始化系统时钟、初始化外部SRAM、设置中断向量表地址。
; x1 a( b& H9 e" P* d8 I( u( K- void SystemInit (void); u) ]) @: p: ^3 U
- { w- a* a- g7 Q$ r7 t* K
- /* 使能内部高速时钟 */
* ]- ?% Q1 T. O# M. z - RCC->CR |= (uint32_t)0x00000001;
* Q4 ?1 c' s# H b0 W7 K
: Z7 ~* P0 O- l% c9 {, H' Z- 8 j9 O* V$ e2 R9 `! q
- #ifndef STM32F10X_CL4 o2 L" B1 X4 s9 W
- RCC->CFGR &= (uint32_t)0xF8FF0000;! u" S) Z; T x, G: a4 i: r1 S
- #else2 D+ w* a, K' F/ F+ V
- RCC->CFGR &= (uint32_t)0xF0FF0000;
. H* V. R# t+ p) v. T( z - #endif
1 k. E& `( C$ K& y3 n4 M
* k _, j8 m9 M! a- /* 禁用PLL、禁用始时钟检测、禁用外部高速时钟 */
1 p% a/ n" g; j" s - RCC->CR &= (uint32_t)0xFEF6FFFF;- \* v8 T |" ?6 y5 s
" i; i7 r0 g+ V; N* N) ?0 V- /* 外部1-25M振荡器未被绕过 */5 F% K& @/ H6 R) ~( F
- RCC->CR &= (uint32_t)0xFFFBFFFF;5 t4 K0 D5 [* L
( V9 W, B0 L+ w& K2 {: \- /* USB预分频器PLL未分频、PLL倍频2、HSE未被分频、HSI/2作为PLL频率 */7 Y! I& }2 _* ~) i* G& r9 y: a
- RCC->CFGR &= (uint32_t)0xFF80FFFF;- Q9 M# b2 w) b Y5 O3 T
- : b9 v: J0 f+ H" n2 H# e" T
- c2 I. b! ]' I$ E9 i
- /* 禁用时钟中断寄存器 */9 _, r4 i( Z4 U% G3 C3 ?" f' l# r
! H4 F, [0 I. l8 v& E- #ifdef STM32F10X_CL
" N6 t! R6 ?( D) ~ - RCC->CR &= (uint32_t)0xEBFFFFFF;2 m& ?' `8 c# d( y8 f4 u
- ) ~2 }: B6 q3 n& F$ g1 q
- RCC->CIR = 0x00FF0000;' L$ x" B; c6 P
- 0 B D; g6 v' ~5 S8 X9 V' Y; r; ]
- RCC->CFGR2 = 0x00000000;
O, ?9 |* Z" j6 `7 ? - #elif defined (STM32F10X_LD_VL) || defined (STM32F10X_MD_VL) || (defined STM32F10X_HD_VL)
, I( U3 u3 S/ ?! h+ r6 y: z2 Z1 p - RCC->CIR = 0x009F0000;
! F' p& {4 l3 @+ ?' t) | - 0 \- y+ t2 C: R& K
- /* Reset CFGR2 register */( Q9 U6 M% [- t& a* c6 o4 \' w
- RCC->CFGR2 = 0x00000000; ; }2 b, l( }) Z% I+ S5 O
- #else3 A' g# ]6 S! _) c
- RCC->CIR = 0x009F0000;2 `& W9 }5 s' {& E0 o" @( _0 g
- #endif /* STM32F10X_CL */
9 v3 O9 D& R; Y, Q2 O" R0 r - , b1 s/ V `0 D2 N1 I/ h
- b& U6 T0 P/ T/ ?+ v9 t- /* 设置外部SRAM */
' _0 i8 b7 H) M5 q - #if defined (STM32F10X_HD) || (defined STM32F10X_XL) || (defined STM32F10X_HD_VL)
. @1 F) z4 B* f7 y { - #ifdef DATA_IN_ExtSRAM+ F9 L7 k0 D; E5 [* D
- SystemInit_ExtMemCtl();
5 H$ \* G4 p- {8 y1 w1 o8 i - #endif /* DATA_IN_ExtSRAM */. w& W) ]. F0 J* x7 z, [6 N
- #endif! R2 {* V4 I7 O3 f+ a3 A
$ r9 Z* k, X. C2 W' p5 f" {- + o* d2 I, C6 N/ ~$ d7 O
- /* 配置系统时钟 */
6 E r' z* [( W7 q7 V - SetSysClock();' b/ F# }- F# g, Q5 } a& `
- - B3 @' }4 H$ K0 {4 F4 n
- - I4 t, x9 U. s/ V
- /*中断向量偏移地址设置 */3 y# y( V, R3 W; W( F: J5 }
9 i+ L) U+ m' l- l, V6 Y; h% W- #ifdef VECT_TAB_SRAM* \7 {- e0 t. `. J' k" I
- SCB->VTOR = SRAM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM. */
: Q! M# k5 J' M! I/ _) `" K: x - #else3 \1 ^: T# S2 b7 u$ G ], C! X7 V
- SCB->VTOR = FLASH_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal FLASH. */
2 b+ V- J/ D/ V, o/ z7 ^! c: R, {/ w - #endif + c- _+ L1 y# ?4 r) T5 \
- }
复制代码
4 K O/ J/ w ^' q3 E6 e6 B/ L' U, C6 }! }5 o9 S3 }0 O3 y: i% K6 P" N
, q3 h" K& j5 T, f
|