msp430g2231通过控制CCR1调节输出PWM占空比来输出占空比不断变化的正弦，三角锯齿波，经过外接RC滤波器后可生产相应的波形-msp430g2231 through the control the CCR1 adjust the output PWM duty cycle output duty cycle of changing the sine, triangle, sawtooth, after the external RC filter to produce the appropriate waveform