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//---------------------------------------------------------- ( u* a8 i$ s: Q, w# D void Delay(uint32_t temp) //¼òµ¥µÄÑÓʱº¯Êý£¬ÓÃÓÚ°´¼üÏû¶¶) O( Q1 A( B- A9 M8 P( T& I) L {/ u( A# n- A3 `. s; ^9 }( G for(; temp != 0; temp--); } ' R4 r5 V, C9 H2 L+ O //---------------------------------------------------------- //----------------------------------------------------------& B% S& s- i# G# L5 Q% f- O+ W unsigned long i;3 b* c: n$ r$ S7 F H . P9 B* N' {" U" C int main(void)6 A8 k7 e" u/ A( O6 n" @- x {. r4 _( J% |7 x/ d9 ~/ `4 `" i unsigned int j; /*!< At this stage the microcontroller clock setting is already configured, this is done through SystemInit() function which is called from startup. X) |* g7 k+ s/ P6 v file (startup_stm32f0xx.s) before to branch to application main.+ J, H" P; I$ H" d+ u1 } To reconfigure the default setting of SystemInit() function, refer to6 d& _/ C$ c7 z8 m* {$ a2 g system_stm32f0xx.c file */ /* GPIOC Periph clock enable */) b$ R6 I- @' K/ A0 Z" l9 \ RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOC, ENABLE);! C. h. k7 b- Y4 g4 _, z' D . c! N6 P7 o- ^/ ?/ p/ A /* Configure PC8 and PC9 in output pushpull mode */6 W M# e, j! G. ]" ]- z, c GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;7 h. `8 v/ i/ M GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;. b9 X' u$ G& ?) z; P GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;* X C3 {. n+ x) Q9 O: P) f" ` GPIO_Init(GPIOC, &GPIO_InitStructure); # j! v* v+ B6 @% s u# v- a //----------------------------------------------------------2 t$ k( W4 U( L2 f //Ê×ÏȶÔkey½øÐгõʼ»¯£¬Ò²¾ÍÊÇÉèÖÃGPIO µÄģʽ* {$ p" l* t7 V$ O, {( m5 z // GPIO_InitTypeDef GPIO_InitStructure; //µ÷ÓÃIO¶¨ÒåµÄ½á¹¹Ìå; H; x+ |8 `" U RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE); //ʹÄܰ´¼üIOµÄʱÖÓ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1 ; //ÉèÖÃÁ¬½Ó°´¼üµÄIO¶Ë¿Ú' C, `% g) D5 ]0 @3 D GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN; //ÉèÖö˿ÚΪÊäÈëģʽ6 \& {- Y5 l" D. R4 t* a. g GPIO_InitStructure.GPIO_Speed = GPIO_Speed_Level_3; //ÉèÖÃËÙ¶ÈΪµÚÈý¼¶ GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; //ÉÏÀÊäÈë$ f! v: n! U" j$ m, c/ j GPIO_Init(GPIOA, &GPIO_InitStructure); //°ÑÉèÖõIJÎÊýÓõ½½á¹¹Ìå0 n5 _& r; g- d B- }& ], T 3 k: |6 @0 t" W. P , n q! V4 g: D% P/ j& w( G /* To achieve GPIO toggling maximum frequency, the following sequence is mandatory. / R6 u1 f& h; M$ U You can monitor PC8 and PC9 on the scope to measure the output signal. If you need to fine tune this frequency, you can add more GPIO set/reset 2 N# @* q7 R# T4 C cycles to minimize more the infinite loop timing.( j9 Z5 A$ k* B c* S- u This code needs to be compiled with high speed optimization option. */ % K9 m" Z; T$ ]1 V, x8 _ while (1)5 a0 ^! J& r3 z: K+ [ { 5 W4 ]# m, ?" c' ^5 c+ Q( E if(GPIO_ReadInputDataBit(GPIOA,GPIO_Pin_0) == 0 ) { & R7 ?# M2 y, H /* Set PC8 and PC9 */ for(j=0;jBSRR |= (0x20BRR |= (0x400>>j); " }5 r( L) G3 a {$ p Delay(5000000);! O4 p+ q @" C }- k& ^8 e& }* z2 u% a% b& h % C" O7 a% w, e4 w) m3 a }; O- X) y6 x$ n6 M else { # Q! q: v) n" ~" x' U7 f /* Set PC9 */( H8 K$ h( E' I' M( u8 m( | - e% C3 w; ] z5 i5 r m. j GPIOC->BSRR |= 0x0200; Delay(1000000); 9 q4 a7 C, {# W/ I% H . }$ X1 M5 p0 h9 b9 g( Q4 i /* Reset PC9 */ GPIOC->BRR |= 0x0200;/ _! r/ e$ M- J8 t Delay(1000000); g) H- g. X% ~' v( v( Z" p2 P : Y; u9 O1 T% x+ a& K" Z }; 2 y8 p- A0 f4 E) J2 V2 B8 Z }. }# e: h/ g' ^/ Y5 }; t/ L } |
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