STM32 TIMER初始化步骤
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STM32 TIMER初始化步骤
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1、使能定時器時鐘:?RCC_APB1PeriphClockCmd();?
例如:
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2、設(shè)置定時器的基本參數(shù)(計數(shù)方式、計數(shù)周期、分頻系數(shù)等)?
注:①計數(shù)方式有TIM_CounterMode_Up(向上計數(shù))、TIM_CounterMode_Down(向下計數(shù))等方式;?
②分頻系數(shù)(TIM_Prescaler)可以為1~65535之間的任意數(shù);?
③計數(shù)初值的計算:(計數(shù)周期 + 1) * (分頻系數(shù) + 1) / (計時器頻率),定時器頻率一般情況下都是默認的從AHB二分頻之后再倍頻得到的,所以說還是72M;?
比如說,要定時100ms,即可寫為:計數(shù)周期 = 999,分頻系數(shù) = 7199 ,即為(999 + 1) * (7199 + 1) / (72,000,000),因為
| 分頻系數(shù) / 計數(shù)器頻率 |
即為計一個數(shù)所用的時間,所以說用計數(shù)總數(shù)乘上這個時間即為總時間。
?
TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Down; //向下計數(shù)TIM_TimeBaseInitStruct.TIM_Period = 4999;TIM_TimeBaseInitStruct.TIM_Prescaler = 7199;TIM_TimeBaseInit(TIM3,&TIM_TimeBaseInitStruct);- 1
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3、定時器中斷配置:
/*定時器中斷參數(shù)設(shè)置*/TIM3->SR &= 0xFFFE; //清除update中斷標志位,否則會出現(xiàn)剛配置完中斷就進入中斷服務(wù)函數(shù)的問題TIM_ITConfig(TIM3,TIM_IT_Update,ENABLE); //配置為更新中斷NVIC_InitStruct.NVIC_IRQChannel = TIM3_IRQn;NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;NVIC_Init(&NVIC_InitStruct);- 1
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4、使能定時器:
TIM_Cmd(TIM3,ENABLE);- 1
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5、編寫中斷服務(wù)函數(shù):
void TIM3_IRQHandler(void) {if(TIM_GetITStatus(TIM3,TIM_FLAG_Update) != RESET){TIM3->SR &= ~(0x01 << 0); //清除中斷標志位flag_1s ++;flag_500ms ++;}if(flag_500ms >= 1){flag_500ms = 0;PBout(5) = !PBout(5);}if(flag_1s >= 2){flag_1s = 0;PDout(12) = !PDout(12);} }- 1
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附上測試源程序:
#include "stm32f10x.h" #include "stm32f10x_rcc.h" #include "delay.h"unsigned char time_count = 0; unsigned char flag_500ms = 0; unsigned char flag_1s = 0;void TIM3_IRQHandler(void) {if(TIM_GetITStatus(TIM3,TIM_FLAG_Update) != RESET){TIM3->SR &= ~(0x01 << 0); //清除中斷標志位flag_1s ++;flag_500ms ++;}if(flag_500ms >= 1){flag_500ms = 0;PBout(5) = !PBout(5);}if(flag_1s >= 2){flag_1s = 0;PDout(12) = !PDout(12);} }int main(void) {unsigned char clear = clear;GPIO_InitTypeDef GPIO_InitStruct;USART_InitTypeDef USART_InitStruct;TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;NVIC_InitTypeDef NVIC_InitStruct;NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); //中斷分組設(shè)置delay_init();/*LED指示燈初始化,用來標志全部初始化完成*/RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);GPIO_InitStruct.GPIO_Speed = GPIO_Speed_10MHz;GPIO_InitStruct.GPIO_Mode = GPIO_Mode_Out_PP;GPIO_InitStruct.GPIO_Pin = GPIO_Pin_5;GPIO_Init(GPIOB,&GPIO_InitStruct);GPIO_SetBits(GPIOB,GPIO_Pin_5);RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD,ENABLE);GPIO_InitStruct.GPIO_Speed = GPIO_Speed_10MHz;GPIO_InitStruct.GPIO_Mode = GPIO_Mode_Out_PP;GPIO_InitStruct.GPIO_Pin = GPIO_Pin_12;GPIO_Init(GPIOD,&GPIO_InitStruct);GPIO_SetBits(GPIOB,GPIO_Pin_5);GPIO_SetBits(GPIOD,GPIO_Pin_12);/*串口端口初始化*/RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE); //串口1時鐘使能RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE); //GPIOA時鐘使能GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_PP;GPIO_InitStruct.GPIO_Pin = GPIO_Pin_9;GPIO_InitStruct.GPIO_Speed = GPIO_Speed_10MHz;GPIO_Init(GPIOA,&GPIO_InitStruct);GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN_FLOATING;GPIO_InitStruct.GPIO_Pin = GPIO_Pin_10;GPIO_InitStruct.GPIO_Speed = GPIO_Speed_10MHz;GPIO_Init(GPIOA,&GPIO_InitStruct);/*串口參數(shù)初始化*/USART_InitStruct.USART_BaudRate = 115200;USART_InitStruct.USART_WordLength = USART_WordLength_8b;USART_InitStruct.USART_StopBits = USART_StopBits_1;USART_InitStruct.USART_Parity = USART_Parity_No;USART_InitStruct.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;USART_InitStruct.USART_HardwareFlowControl = USART_HardwareFlowControl_None;USART_Init(USART1,&USART_InitStruct);//USART1->SR = USART1->SR;USART_Cmd(USART1,ENABLE);/*定時器3基本參數(shù)初始化*/RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE); //開定時器3時鐘TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Down; //向下計數(shù)TIM_TimeBaseInitStruct.TIM_Period = 4999;TIM_TimeBaseInitStruct.TIM_Prescaler = 7199;TIM_TimeBaseInit(TIM3,&TIM_TimeBaseInitStruct);/*定時器中斷參數(shù)設(shè)置*/TIM3->SR &= 0xFFFE; //清除update中斷標志位,否則會出現(xiàn)剛配置完中斷就進入中斷服務(wù)函數(shù)的問題TIM_ITConfig(TIM3,TIM_IT_Update,ENABLE); //配置為更新中斷NVIC_InitStruct.NVIC_IRQChannel = TIM3_IRQn;NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;NVIC_Init(&NVIC_InitStruct);/*初始化完成*/GPIO_ResetBits(GPIOB,GPIO_Pin_5);GPIO_ResetBits(GPIOD,GPIO_Pin_12);TIM_Cmd(TIM3,ENABLE);while(1){} }總結(jié)
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