LM3S系列PWM问题

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laocuo1142| 资深工程师

楼主 | 2020-11-12 17:11 | 只看该作者回帖奖励

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PWM, lm, pi, se, IO

我想用LM3S系产生PWM方波来驱动蜂鸣器下面是我参考资料写的程序，但是看示波器，怎么也不产生方波，请哪位高手帮助分析一下啊~
#include "hw_types.h"
#include "gpio.h"
#include "sysctl.h"
#include "hw_memmap.h"
#include "pwm.h"
#include "lm3s5t36.h"
unsigned long TheSysClock ;
#define uint unsigned int
#define uchar unsigned char
int main()
{
      SysCtlClockSet(SYSCTL_SYSDIV_2|SYSCTL_USE_OSC|SYSCTL_OSC_MAIN|SYSCTL_XTAL_16MHZ);
      SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB); //Ê¹ÄÜB¿Ú
      SysCtlPeripheralEnable(SYSCTL_PERIPH_PWM);          // Ê¹ÄÜPWM¿Ú
      SysCtlPWMClockSet(SYSCTL_PWMDIV_1); //8·ÖÆµ=2M
      TheSysClock = SysCtlClockGet();

      GPIOPinTypeGPIOOutput(GPIO_PORTB_BASE,GPIO_PIN_0);
      GPIOPadConfigSet(GPIO_PORTB_BASE,GPIO_PIN_0,GPIO_STRENGTH_8MA,GPIO_PIN_TYPE_STD);
      GPIOPinTypePWM(GPIO_PORTB_BASE, GPIO_PIN_0 );  // PB0andPB1
      GPIOPinTypePWM(GPIO_PORTB_BASE, GPIO_PIN_1 );
      PWMGenConfigure(PWM_BASE, PWM_GEN_1,PWM_GEN_MODE_UP_DOWN | PWM_GEN_MODE_NO_SYNC); //·¢ÉúÆ÷1£¬µÝ¼õ£¬
      PWMGenPeriodSet(PWM_BASE, PWM_GEN_1, 6000);
      PWMPulseWidthSet(PWM_BASE, PWM_OUT_2, 4200);
      PWMPulseWidthSet(PWM_BASE, PWM_OUT_3, 1800);
      PWMOutputState(PWM_BASE,PWM_OUT_2_BIT, true);
      PWMGenEnable(PWM_BASE, PWM_GEN_1);

            while(1)
      {
      }
}

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