利用msp430f149控制程控增益放大器VCA810实现手动增益以及自动增益的功能，并在12864液晶显示屏上增益值和正弦波有效值-Use msp430f149 Control Programmable Gain Amplifier Gain VCA810 achieved manually and automatic gain function, and in the 12,864 gain value on the LCD screen and sine RMS