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环境:iar arm 5.3
stm32f103vbt6
使用PA.8 外部输入10Mhz的方波。可从systick中断得到数据4.
4×5000(预分频值)×1000(tick中断时间)=20MHz
属于双边沿检测,一个PA.8个脉冲有2个边沿,所以时钟加倍。
由于使用了TI1F_ED它的结构如下:
void RCC_Configuration( void ) { /* Setup STM32 system (clock, PLL and Flash configuration) */ SystemInit( ); /* Enable GPIOA, GPIOC and USART1 clock */ RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOC | RCC_APB2Periph_TIM1, ENABLE ); } GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOA, &GPIO_InitStructure); void TIM1_Init( void ) { TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; TIM_TimeBaseStructure.TIM_Period = 65535; TIM_TimeBaseStructure.TIM_Prescaler = 5000; TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; TIM_TimeBaseInit( TIM1, &TIM_TimeBaseStructure ); TIM_TIxExternalClockConfig( TIM1, TIM_TIxExternalCLK1Source_TI1ED, TIM_ICPolarity_Rising, 0 ); TIM_Cmd( TIM1, ENABLE ); } int main( void ) { RCC_Configuration( ); GPIO_Config( ); TIM1_Init( ); /* Setup SysTick Timer for 1 msec interrupts */ if ( SysTick_Config( SystemFrequency / 1000 ) ) { /* Capture error */ while ( 1 ) ; } while ( 1 ) { } } void SysTick_Handler( void ) { static u32 i = 0; if ( i == 0 ) { i = 1; gusData = 0; TIM_SetCounter( TIM1, 0 ); } else { i = 0; gusData = TIM_GetCounter( TIM1 ); } }
sTM32 使用TIMx_CH1作为 Tx1F_ED 计数器时钟
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原文地址:http://www.cnblogs.com/shangdawei/p/4765203.html