int main()
{
SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
SYSCTL_XTAL_16MHZ);
SysCtlPWMClockSet(SYSCTL_PWMDIV_1);
SysCtlPeripheralEnable(SYSCTL_PERIPH_PWM0);
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC);
GPIOPinConfigure(GPIO_PC5_M0PWM7);
GPIOPinTypePWM(GPIO_PORTC_BASE, GPIO_PIN_5);
PWMGenConfigure(PWM0_BASE, PWM_GEN_3, PWM_GEN_MODE_DOWN |
PWM_GEN_MODE_NO_SYNC);
PWMGenPeriodSet(PWM0_BASE, PWM_GEN_3, 100);
PWMPulseWidthSet(PWM0_BASE, PWM_OUT_3, 25);
PWMOutputState(PWM0_BASE, PWM_OUT_7_BIT, true);
PWMGenEnable(PWM0_BASE, PWM_GEN_3);
while(1)
{
}
}
程序运行后用示波器量相应的引脚，却没有想要的方波出现啊？求大神帮忙看看，什么原因。
