1602液晶的实用的详细程序。程序仅供参考

-Pin VREF requires a voltage of 1.25 V to 2.5 V, with gain

scaling between 40 dB/V and 20 dB/V, respectively. Voltage

VGN controls the gain　its nominal operating range is from

0.25 V to 2.65 V for 20 dB/V gain scaling, and 0.125 V to

1.325 V for 40 dB/V scaling. When this pin is taken to ground,

the channel will power down and disable its output.