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//---------------------------------------------------------- void Delay(uint32_t temp) //¼òµ¥µÄÑÓʱº¯Êý£¬ÓÃÓÚ°´¼üÏû¶¶ { for(; temp != 0; temp--); } . _' q7 X. U* l j! U4 u! y ' v7 X. U R7 i7 h9 d$ J //----------------------------------------------------------6 L' r: Z$ U5 r' X* a3 C4 r& s //---------------------------------------------------------- unsigned long i;( L# n0 T0 C* F ) l" {) c G! ~6 e1 K int main(void) {1 y( o% i6 V( A unsigned int j;" g1 E% ~8 n2 E7 s /*!< At this stage the microcontroller clock setting is already configured, * H# v+ n! s7 n; b9 [6 h2 c this is done through SystemInit() function which is called from startup1 B9 Q% H3 J% ~4 M9 T2 n file (startup_stm32f0xx.s) before to branch to application main. To reconfigure the default setting of SystemInit() function, refer to2 q+ }+ S' ]$ k8 A7 H system_stm32f0xx.c file# h1 `$ Y3 E) W& m! J */ /* GPIOC Periph clock enable */& c0 E9 Z! h6 p) d/ s+ V6 ? RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOC, ENABLE);+ W- I, H( E7 Q! A4 F0 U * F+ _6 b( _3 t+ D) q, | /* Configure PC8 and PC9 in output pushpull mode */5 \, b5 e$ k2 P& {0 @% S GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9;: G: N7 S j' a GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT; GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;0 |& C9 T6 b6 L- j: f) y" s GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;0 h$ R$ g, `5 t* e3 B$ d9 u& \( h GPIO_Init(GPIOC, &GPIO_InitStructure);" I: K* D' k1 f5 V, [, w % {& Y0 F) N3 T' x# u //---------------------------------------------------------- 5 w; \$ I7 y; ^ l( y" Q //Ê×ÏȶÔkey½øÐгõʼ»¯£¬Ò²¾ÍÊÇÉèÖÃGPIO µÄģʽ2 @! _5 D! z0 E e" Z! ^$ u // GPIO_InitTypeDef GPIO_InitStructure; //µ÷ÓÃIO¶¨ÒåµÄ½á¹¹Ìå3 _: F: S" x1 |$ Q7 q3 ` L RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE); //ʹÄܰ´¼üIOµÄʱÖÓ+ O A( e$ r* G3 d GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1 ; //ÉèÖÃÁ¬½Ó°´¼üµÄIO¶Ë¿Ú. J8 Q; Q5 E' h3 ? GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN; //ÉèÖö˿ÚΪÊäÈëģʽ GPIO_InitStructure.GPIO_Speed = GPIO_Speed_Level_3; //ÉèÖÃËÙ¶ÈΪµÚÈý¼¶ GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; //ÉÏÀÊäÈë) d0 Q0 q0 Y0 |2 V6 ^- I8 p GPIO_Init(GPIOA, &GPIO_InitStructure); //°ÑÉèÖõIJÎÊýÓõ½½á¹¹Ìå9 \" i. r& V) Y& [; b5 Y ( D2 [9 R [7 W8 A) Y, ^9 o 8 E: u1 x. K0 ^* d+ A- |( C4 K- y/ v % ~! j2 v# P1 V6 s# Z/ z /* To achieve GPIO toggling maximum frequency, the following sequence is mandatory. You can monitor PC8 and PC9 on the scope to measure the output signal. 7 {; F. l+ O, U1 I6 I7 x% u If you need to fine tune this frequency, you can add more GPIO set/reset # R' J, l& l% K cycles to minimize more the infinite loop timing.8 C2 H, \& Y$ H8 y This code needs to be compiled with high speed optimization option. */ while (1) { if(GPIO_ReadInputDataBit(GPIOA,GPIO_Pin_0) == 0 ) ; O' b! K- @5 |- {$ k# j5 f, g. @3 f { /* Set PC8 and PC9 */' W/ }) @% }( C# V' o( M) p1 e for(j=0;jBSRR |= (0x20BRR |= (0x400>>j); 9 [) h* G+ X# P Delay(5000000); }1 x4 l8 S6 B$ R* [9 P. i9 ^# W1 E) w! Y } else { 8 {8 V! E5 J# y$ T1 ~0 G! I& ^ /* Set PC9 */ ) @5 O. H) l D* |, Y GPIOC->BSRR |= 0x0200; Delay(1000000); ! K* y; B( {6 S5 F1 d) ` /* Reset PC9 */ 3 I6 F& H+ p, o! {1 Y GPIOC->BRR |= 0x0200; Delay(1000000); : }1 W4 i* o* y( V0 W) q8 L' P$ S, k };$ c+ ~& S7 m4 q3 t- @/ `; `3 ]1 \9 H ( Y+ S& O" a0 u8 l, n & }% y2 K# I/ Z' c$ [* A }, R; n. S3 o M7 a. t" k$ | } |
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