本帖最后由 小猫薄薄 于 2014-5-3 21:19 编辑
现在可以用stm32 tim_ert实现对脉冲的计数功能，如何才能实现对脉冲的频率计算呢？ 对于高频脉冲（MhZ）的频率计算可以通过f=n/t实现，t取值10ms，如何才能实现对脉冲计数的精确定时呢？10ms定时已经解决，串口数据发送错误不知怎么回事？ 如果把tim2的中断取消，就不会产生错误。
tim3计数代码粘贴如下，请问如何实现10ms 的精确定时
# include "Tim3.h"
void Tim3_Config(void){
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
/*PD2作为频率输入端口*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOD, &GPIO_InitStructure);
TIM_DeInit(TIM3);
TIM_TimeBaseStructure.TIM_Period =0xFFFF;//当计数器从0记到FFF为一个周期,自动装载寄存器ARR中的值
TIM_TimeBaseStructure.TIM_Prescaler = 0X00;
TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;//设置时钟系数 不分频
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;//向上计数模式
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); // Time base configuration
/* ------------------------------------------------------------------------------------------
* TIM_ExtTRGPSC_OFF tim ETRP 预分频0
* TIM_ExtTRGPolarity_Inverted 外部触发极性非翻转：高电平或上升沿有效
*0 外部触发滤波器 再0x0-0xf之间 经过多少个周期认为脉冲稳定
-------------------------------------------------------------------------------------------*/
TIM_ITRxExternalClockConfig(TIM3,TIM_TS_ETRF);
TIM_ETRClockMode2Config(TIM3, TIM_ExtTRGPSC_OFF, TIM_ExtTRGPolarity_Inverted, 0);
TIM_SetCounter(TIM3, 0); //设置计数器为0
TIM_Cmd(TIM3, ENABLE);
//TIM_ITConfig(TIM3, TIM_IT_Update, ENABLE);
}
/*void NVIC_Config(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
/* Enable the TIM3 global Interrupt
NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
*/
tim2 和中断函数配置如下
void Tim2_Config(){
TIM_TimeBaseInitTypeDef TIM2_TimeBaseStructure;
NVIC_InitTypeDef NVIC_InitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
TIM_DeInit(TIM2);
TIM2_TimeBaseStructure.TIM_Period =10000;
TIM2_TimeBaseStructure.TIM_Prescaler = 71;
TIM2_TimeBaseStructure.TIM_ClockDivision = 0x0;//ÉèÖÃʱÖÓϵÊý ²»·ÖƵ
TIM2_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;//ÏòÉϼÆÊýģʽ
TIM_TimeBaseInit(TIM2, &TIM2_TimeBaseStructure); // Time base configuration
TIM_ClearFlag(TIM2,TIM_FLAG_Update);//Çå³þ¸üбê־λ
TIM_ITConfig(TIM2,TIM_IT_Update,ENABLE );
NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
TIM_Cmd(TIM2, ENABLE);
}
void TIM2_IRQHandler(void)
{
if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET)
{
TIM_ClearITPendingBit(TIM2, TIM_IT_Update );
Frequency_value = TIM_GetCounter(TIM3);
}
}
串口收到的数据如下，前两个字节就是计数值Frequency_value，中间红色部分确是有数据发送错误是怎么回事？、
A0 5B 00 00 0D 0A
53 76 00 00 0D 0A
06 91 00 00 0D 0A
B9 AC 00 00 0D 0A
6C C7 00 00 0D 0A
1F E2 00 00 0D 0A
D2 FD 00 00 0D 0A
86 18 00 00 0D 0A
39 33 00 00 0D 0A
EC 4E 00 00 0D 0A
9F 69 00 00 0D 0A
52 84 00 00 0D 0A
05 9F 00 00 0D 0A
B8 BA 00 00 0D 0A
6B D5 00 00 0D 0A
1E F0 00 00 0D 0A
D2 0B 00 00 0D 0A
85 26 00 00 0D 0A
38 41 00 00 0D 0A
EB 5C 00 FF FF 6E
9E F9 FF FF FF 6C
00 F9 FF FF FF 69
00 F9 FF FF FF 67
00 F9 FF FF FF 65
00 F9 FF FF FF 62
28 87 00 00 0D 0A
DB A2 00 00 0D 0A
8E BD 00 00 0D 0A
41 D8 00 00 0D 0A
F4 F3 00 00 0D 0A
A8 0E 00 00 0D 0A
5B 29 00 00 0D 0A
0E 45 00 00 0D 0A
C1 60 00 00 0D 0A
串口配置如下
#include "uart.h"
void uart_Init(void){
GPIO_InitTypeDef GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;
RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOA, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE );
/*
* USART1_TX -> PA9 , USART1_RX ->PA10
*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9|GPIO_Pin_10;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);
USART_InitStructure.USART_BaudRate = 115200;
USART_InitStructure.USART_WordLength = USART_WordLength_8b;
USART_InitStructure.USART_StopBits = USART_StopBits_1;
USART_InitStructure.USART_Parity = USART_Parity_No;
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
USART_Init(USART1, &USART_InitStructure);
USART_Cmd(USART1, ENABLE);
}
int fputc(int ch, FILE *f){
USART_SendData(USART1, (unsigned char) ch);
//while (!(USART1->SR & USART_FLAG_TXE));
while( USART_GetFlagStatus(USART1,USART_FLAG_TC)!= SET);
return (ch);
}
void UART_send_byte(uint8_t byte)
{
while(!((USART1->SR)&(1<<7)));
USART1->DR=byte;
}
void UART_Send(uint8_t *Buffer, uint32_t Length)
{
while(Length != 0)
{
while(!((USART1->SR)&(1<<7)));//µÈ´ý·¢ËÍÍê
USART1->DR= *Buffer;
Buffer++;
Length--;
}
}
uint8_t UART_Recive(void)
{
while(!(USART1->SR & (1<<5)));
return(USART1->DR);
}
代码已经测试可以对脉冲进行计数，计数到达65535以后清零重新计数，如何实现10ms精确定时？
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