nuc120开发板学习之定时器中断方式实现每秒输出数字加1

只看该作者 · 2011-8-16 10:56

本帖最后由缥缈九哥于 2012-9-14 12:07 编辑

上次用软件延时实现了LED灯的渐亮渐暗，用软件延时的实际用处不大，故开始定时器的学习。准备实现利用定时器中断方式实现每秒输出数字加1。

只看该作者 · 2011-8-16 10:59

上传定时器的学习笔记

只看该作者 · 2011-8-16 11:01

程序源码

/*---------------------------------------------------------------------------------------------------------*/
/*                                                                                                       */
/* Copyright(c) 2009 Nuvoton Technology Corp. All rights reserved.                                        */
/*                                                                                                       */
/*---------------------------------------------------------------------------------------------------------*/
#include <stdio.h>

/*---------------------------------------------------------------------------------------------------------*/
/*  Include hear file                                                                        */
/*---------------------------------------------------------------------------------------------------------*/

#include "NUC1xx.h"
#include "DrvGPIO.h"

/*----------------------------------------------------------------------------
  Define variable
  ----------------------------------------------------------------------------*/
static uint32_t TimerCOUN=0;
/*----------------------------------------------------------------------------
  Function subroutine
  ----------------------------------------------------------------------------*/
void Delay(uint32_t delayCnt)
{
while(delayCnt--)
{
      __NOP();
      __NOP();
}
}
uint32_t GetTDR(void)
{
return TIMER0->TDR;
}
/*----------------------------------------------------------------------------
  Interrupt subroutine
  ----------------------------------------------------------------------------*/
void TMR0_IRQHandler(void) // Timer0 interrupt subroutine
{
TIMER0->TISR.TIF =1;
TimerCOUN++;
}
/*----------------------------------------------------------------------------
  MAIN function
  ----------------------------------------------------------------------------*/
int32_t main (void)
{
uint32_t TEMP=0;

/* SYSCLK =>12Mhz*/
UNLOCKREG();
SYSCLK->PWRCON.XTL12M_EN = 1;
LOCKREG();
/*set GPI0 output*/
DrvGPIO_Open(E_GPA,2, E_IO_OUTPUT);
DrvGPIO_Open(E_GPA,3, E_IO_OUTPUT);
DrvGPIO_Open(E_GPA,4, E_IO_OUTPUT);
DrvGPIO_Open(E_GPA,5, E_IO_OUTPUT);

NVIC_DisableIRQ(TMR0_IRQn); //Disable Timer0 interrupt
outpw(&TIMER0->TCSR ,0 ); //Disable Timer0

/* Step 1. Enable and Select Timer clock source */
SYSCLK->CLKSEL1.TMR0_S = 7; //Select 22Mhz for Timer0 clock source
SYSCLK->APBCLK.TMR0_EN =1; //Enable Timer0 clock source

/* Step 2. Select Operation mode */
TIMER0->TCSR.MODE=1; //Select periodic mode for operation mode

/* Step 3. Select Time out period = (Period of timer clock input) * (8-bit Prescale + 1) * (24-bit TCMP)*/
TIMER0->TCSR.PRESCALE=0; // Set Prescale [0~255]
TIMER0->TCMPR = 2765; // Set TCMPR [0~16777215]
// (1/22118400)*(0+1)*(2765)= 125.01usec or 7999.42Hz

/* Step 4. Enable interrupt */
TIMER0->TCSR.IE = 1;
TIMER0->TISR.TIF = 1; //Write 1 to clear for safty
NVIC_EnableIRQ(TMR0_IRQn); //Enable Timer0 Interrupt

/* Step 5. Enable Timer module */
TIMER0->TCSR.CRST = 1; //Reset up counter
TIMER0->TCSR.CEN = 1; //Enable Timer0

    TIMER0->TCSR.TDR_EN=1; // Enable TDR function

while(1)
{
if (TimerCOUN>8000) //Wait 1 seconds
{
TEMP++;
   TimerCOUN=0;
DrvGPIO_SetPortBits(E_GPA, ~(TEMP<<2));

}
}
}