1 VCC+5V C1 106 J2 4 3 2 1 USB A B C D 2 3 4 R1 221 C2 104 VCC+3V3 J1 VD1 3V3 C3 106 6 5 4 3 2 1 CON6 （短路VCC+5V到CH340G_VCC：CH340G供电为5V，TTL电平为5V） （短路VCC+3V3到CH340G_VCC：CH340G供电为3V3，TTL电平为3V3） VCC+5V CH340G_VCC VCC+3V3 CH340G_TXD CH340G_RXD GND VCC+5V：从USB取出来的5V电源 CH340G_VCC:模块供电点 VCC+3V3：模块稳压出来的3V3电源（3.0V－3.6V） CH340G_TXD：串行数据输出 CH340G_RXD：串行数据输入 GND：模块接地（与目标系统地相连） GND VCC+5V GND CH340G_TXD CH340G_RXD CH340G_3V3 Y1 U1 GND TXD RXD V3 UD+ UD- XI XO 1 2 3 4 5 6 7 8 CH340G_VCC 16 15 14 13 12 11 10 9 VCC R232 RTS# DTR# DCD# RI# DSR# CTS# CH340G 12M C5 22 C6 22 VCC+5V CH340G_VCC CH340G_VCC CH340G_3V3 R2 472 R3 472 R4 472 C4 104 LED1 PWR LED2 TXD LED3 RXD D X T _ G 0 4 3 H C D X R _ G 0 4 3 H C A B C D 1 2 3 4