标题: FTM输出PWM波 [打印本页]

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作者: 希达雅姿    时间: 2018-11-13 16:24
标题: FTM输出PWM波
/*
* main implementation: use this 'C' sample to create your own application
*
*/





#include "derivative.h" /* include peripheral declarations */
#include "common.h"



int main(void)
{
        SysInit(); // initialize system clock and SysTick timer

        // FTM2_CH0 Pin Select
        SIM_PINSEL1 |= SIM_PINSEL1_FTM2PS0(2); // select FTM2_CH0 on PTF0
               
        SIM_SCGC |= SIM_SCGC_FTM2_MASK; // enable FTM clock
    FTM2_C0SC = FTM_CnSC_MSB_MASK | FTM_CnSC_ELSB_MASK; // edge-aligned PWM, high-true pulse
    FTM2_C0V = 2000; // set channel value, PWM duty = 20%
    FTM2_MOD = 9999; // set modulo value, PWM frequency = 2KHz
    FTM2_SC |= FTM_SC_CLKS(1) | FTM_SC_PS(0); // FTM clock = system clock/OUTDIV3/PS = 40/2/1 = 20MHz
        NVIC_ISER |= 1 << (INT_FTM2 - 16); // enable FTM interrupt in NVIC register
    FTM2_SC |= FTM_SC_TOIE_MASK; // enables FTM overflow interrupt

        for(;;)
        {         

        }
       
        return 0;
}

void FTM2_IRQHandler(void)
{   
        static int cnv = 0;
       
        FTM2_SC &= ~FTM_SC_TOF_MASK; // clear FTM interrupt flag
       
        FTM2_C0V = cnv; // change duty
        cnv += 5;
        if (cnv > 10000)
        {
                cnv = 0;
        }
}

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