不对吧,这个官方提供的有库函数和参考例子,虽然不是满足你这个需求,但是类似
/******************************************************************************
* [url=home.php?mod=space&uid=288409]@file[/url] main.c
* [url=home.php?mod=space&uid=895143]@version[/url] V1.00
* $Revision: 3 $
* $Date: 15/05/28 10:37a $
* [url=home.php?mod=space&uid=247401]@brief[/url] Use the timer pin P3.2 to demonstrate timer trigger counting mode
* function. And displays the measured input frequency to UART console.
*
* @note
* Copyright (C) 2015 Nuvoton Technology Corp. All rights reserved.
*****************************************************************************/
#include <stdio.h>
#include "Mini58Series.h"
void TMR0_IRQHandler(void)
{
uint32_t t = TIMER_GetCaptureData(TIMER0);
// Timer clock source us 22.1184M
printf("Input frequency is %dHz\n", 22118400 / t);
TIMER_ClearCaptureIntFlag(TIMER0);
}
void SYS_Init(void)
{
/*---------------------------------------------------------------------------------------------------------*/
/* Init System Clock */
/*---------------------------------------------------------------------------------------------------------*/
/* Unlock protected registers */
SYS_UnlockReg();
/* Set P5 multi-function pins for XTAL1 and XTAL2 */
SYS->P5_MFP &= ~(SYS_MFP_P50_Msk | SYS_MFP_P51_Msk);
SYS->P5_MFP |= (SYS_MFP_P50_XT1_IN | SYS_MFP_P51_XT1_OUT);
/* Enable external 12MHz XTAL (UART), and HIRC */
CLK->PWRCTL = CLK_PWRCTL_XTL12M | CLK_PWRCTL_HIRCEN_Msk;
/* Waiting for clock ready */
CLK_WaitClockReady(CLK_STATUS_XTLSTB_Msk | CLK_STATUS_HIRCSTB_Msk);
/* Enable UART and Timer 0 clock */
CLK->APBCLK = CLK_APBCLK_UART0CKEN_Msk | CLK_APBCLK_TMR0CKEN_Msk;
/* Select UART clock source from external crystal*/
CLK->CLKSEL1 = (CLK->CLKSEL1 & ~CLK_CLKSEL1_UARTSEL_Msk) | CLK_CLKSEL1_UARTSEL_XTAL;
/* Update System Core Clock */
/* User can use SystemCoreClockUpdate() to calculate SystemCoreClock and CycylesPerUs automatically. */
SystemCoreClockUpdate();
/*---------------------------------------------------------------------------------------------------------*/
/* Init I/O Multi-function */
/*---------------------------------------------------------------------------------------------------------*/
/* Set P1 multi-function pins for UART RXD, TXD */
SYS->P1_MFP = SYS_MFP_P12_UART0_RXD | SYS_MFP_P13_UART0_TXD;
/* Set P3 multi function pin for Timer 0 capture pin */
SYS->P3_MFP = SYS_MFP_P32_TM0_EXT;
/* Lock protected registers */
SYS_LockReg();
}
int main(void)
{
int volatile i;
/* Init System, IP clock and multi-function I/O
In the end of SYS_Init() will issue SYS_LockReg()
to lock protected register. If user want to write
protected register, please issue SYS_UnlockReg()
to unlock protected register if necessary */
SYS_Init();
/* Init UART to 115200-8n1 for print message */
UART_Open(UART0, 115200);
printf("\nThis sample code demonstrate timer trigger counting mode.\n");
printf("Please connect input source with Timer 0 capture pin T0EX (P3.2), press any key to continue\n");
getchar();
// Give a dummy target frequency here. Will over write capture resolution with macro
TIMER_Open(TIMER0, TIMER_PERIODIC_MODE, 1000000);
// Update prescale to set proper resolution.
TIMER_SET_PRESCALE_VALUE(TIMER0, 0);
// Set compare value as large as possible, so don't need to worry about counter overrun too frequently.
TIMER_SET_CMP_VALUE(TIMER0, 0xFFFFFF);
// Configure Timer 0 free counting mode, capture TDR value on rising edge
TIMER_EnableCapture(TIMER0, TIMER_CAPTURE_TRIGGER_COUNTING_MODE, TIMER_CAPTURE_RISING_EDGE);
// Start Timer 0
TIMER_Start(TIMER0);
// Enable timer interrupt
TIMER_EnableCaptureInt(TIMER0);
NVIC_EnableIRQ(TMR0_IRQn);
while(1);
}
/*** (C) COPYRIGHT 2015 Nuvoton Technology Corp. ***/
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