/**************************************************************************//**
* [url=home.php?mod=space&uid=288409]@file[/url] main.c
* @brief
* Demonstrate how to use the TIMER0 capture function to capture
* both edge of external capture signal and calculate the time
* of high level duration of capture signal.
* @note
* Copyright (C) 2013 Nuvoton Technology Corp. All rights reserved.
******************************************************************************/
#include <stdio.h>
#include "M0518.h"
/****************************************************************************/
/* Define */
/****************************************************************************/
#define HCLK_CLOCK 50000000
/****************************************************************************/
/* Global variables */
/****************************************************************************/
volatile uint32_t g_au32TMRCapCountRise, g_au32TMRCapCountFall, g_u32TimerCapFlag;
/****************************************************************************/
/* Functions */
/****************************************************************************/
/*------------------------------*/
/* TIMER0 interrupt handler */
/*------------------------------*/
void TMR0_IRQHandler(void)
{
if (TIMER_GetCaptureIntFlag(TIMER0) == 1)
{
/* Clear TIMER0 capture interrupt flag */
TIMER_ClearCaptureIntFlag(TIMER0);
if (PB15)
{
/* Save the capture counter for PB15 rising edge */
g_au32TMRCapCountRise = TIMER_GetCaptureData(TIMER0);
}
else
{
/* Save the capture counter for PB15 falling edge */
g_au32TMRCapCountFall = TIMER_GetCaptureData(TIMER0);
g_u32TimerCapFlag = 1;
}
}
}
void SYS_Init(void)
{
/*------------------------------*/
/* Init System Clock */
/*------------------------------*/
/* Enable HIRC clock */
CLK_EnableXtalRC(CLK_PWRCON_IRC22M_EN_Msk);
/* Waiting for HIRC clock ready */
CLK_WaitClockReady(CLK_CLKSTATUS_IRC22M_STB_Msk);
/* Switch HCLK clock source to HIRC */
CLK_SetHCLK(CLK_CLKSEL0_HCLK_S_HIRC, CLK_CLKDIV_HCLK(1));
/* Enable HXT */
CLK_EnableXtalRC(CLK_PWRCON_XTL12M_EN_Msk);
/* Waiting for clock ready */
CLK_WaitClockReady(CLK_CLKSTATUS_XTL12M_STB_Msk);
/* Set core clock as HCLK_CLOCK from PLL and SysTick source to HCLK/2*/
CLK_SetCoreClock(HCLK_CLOCK);
/* Enable peripheral clock */
CLK_EnableModuleClock(UART0_MODULE);
CLK_EnableModuleClock(TMR0_MODULE);
/* Peripheral clock source */
CLK_SetModuleClock(UART0_MODULE, CLK_CLKSEL1_UART_S_PLL, CLK_CLKDIV_UART(1));
CLK_SetModuleClock(TMR0_MODULE, CLK_CLKSEL1_TMR0_S_HCLK, 0);
/*------------------------------*/
/* Init I/O Multi-function */
/*------------------------------*/
/* Set PB multi-function pins for UART0 RXD, TXD */
SYS->GPB_MFP = SYS_GPB_MFP_PB0_UART0_RXD | SYS_GPB_MFP_PB1_UART0_TXD;
/* Set PB multi-function pins for TM0_EXT on PB.15 */
SYS->GPB_MFP |= (SYS_GPB_MFP_PB15_TM0_EXT);
SYS->ALT_MFP = SYS_ALT_MFP_PB15_TM0_EXT;
}
void UART0_Init(void)
{
/*------------------------------*/
/* Init UART */
/*------------------------------*/
/* Reset UART IP */
SYS_ResetModule(UART0_RST);
/* Configure UART0 and set UART0 Baudrate */
UART_Open(UART0, 115200);
}
/*------------------------------*/
/* Main Function */
/*------------------------------*/
int main(void)
{
uint32_t u32CAPValue = 0;
uint32_t u32delayCounter;
/* Unlock protected registers */
SYS_UnlockReg();
/* Init System, peripheral clock and multi-function I/O */
SYS_Init();
/* Lock protected registers */
SYS_LockReg();
/* Init UART0 for printf */
UART0_Init();
printf("CPU [url=home.php?mod=space&uid=72445]@[/url] %d Hz\n", SystemCoreClock);
printf("+------------------------------------------+\n");
printf("| TIMER0 Capture Counter Sample Code |\n");
printf("+------------------------------------------+\n\n");
printf(" * Please connect PB14 and PB15 by wire.\n");
/* Config PB14 to GPIO output mode to generate a pulse as external capture signal */
PB14 = 0;
GPIO_SetMode(PB, BIT14, GPIO_PMD_OUTPUT);
/*----- Initial TIMER0 -----*/
SYS_ResetModule(TMR0_RST);
TIMER_Open(TIMER0, TIMER_CONTINUOUS_MODE, 1);
/* Configure TIMER0 setting for external counter input and capture function */
/* Set TIMER0 clock to HCLK/(1+1) */
TIMER_SET_PRESCALE_VALUE(TIMER0, 1);
printf("TIMER0 clock @ %d Hz\n", SystemCoreClock / 2);
/* Reset TIMER0 counter value */
TIMER_SET_CMP_VALUE(TIMER0, 0xFFFFFF);
/* Set TIMER0 to capture both edges */
TIMER_EnableCapture(TIMER0, TIMER_CAPTURE_FREE_COUNTING_MODE, TIMER_CAPTURE_FALLING_AND_RISING_EDGE);
/* Enable TIMER0 capture interrupt */
TIMER_EnableCaptureInt(TIMER0);
NVIC_EnableIRQ(TMR0_IRQn);
/*---- Begin to test -----*/
g_au32TMRCapCountRise = g_au32TMRCapCountFall = g_u32TimerCapFlag = 0;
/* Start TIMER0 counting */
TIMER_Start(TIMER0);
/* Generate a pulse with both rising edge and falling edge to PB14 */
PB14 = 1; /* Rising edge */
/* Delay to keep high level of pulse. */
/* Change the delay counter will get different capture counter value */
for (u32delayCounter = 0; u32delayCounter < 10000; u32delayCounter++);
PB14 = 0; /* Falling edge */
/* Wait a rising edge and a falling edge from PB15 */
/* TIMER0 interrupt handler will set g_u32TimerCapFlag to 1 when received */
/* external capture signal from PB15 */
while (g_u32TimerCapFlag == 0);
/* Got the counter value for external capture signal */
if (g_au32TMRCapCountFall > g_au32TMRCapCountRise)
u32CAPValue = g_au32TMRCapCountFall - g_au32TMRCapCountRise;
else
/* In the case that TIMER0 counter overflowed */
u32CAPValue = 0xffffff - g_au32TMRCapCountRise + g_au32TMRCapCountFall;
printf("Capture counter for rising edge: 0x%X (%d)\n", g_au32TMRCapCountRise, g_au32TMRCapCountRise);
printf("Capture counter for falling edge: 0x%X (%d)\n", g_au32TMRCapCountFall, g_au32TMRCapCountFall);
printf("\n");
printf("Capture counter for high level duration: 0x%X (%d)\n", u32CAPValue, u32CAPValue);
printf("The high level duration time should be about (TIMER0 clock) * %d\n", u32CAPValue);
printf(" = %d us\n", u32CAPValue / (SystemCoreClock / 2 / 1000000));
/* Stop TIMER0 counting */
TIMER_Close(TIMER0);
while (1);
}
/*** (C) COPYRIGHT 2013 Nuvoton Technology Corp. ***/
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