Yuga CLM920_AC3 - Page 33

CLM920_AC3 Module Hardware Usage Guide
Shanghai Yuge Information Technology co., LTD
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68
RXD
DI
UART receive
data
VIH
1.2
1.8
2
VIL
-0.3
0.6
When the user wants to use the 4-wire serial port, you can refer to the following
connection methods
Figure 3-13 Four-wire serial port design
If you need to use a 2-wire serial port, you can refer to the following serial port design.
Figure 3-14 Two-wire serial port design
The serial port of the module is TTL 1.8V level. If the serial port needs to be connected
with the MCU of 3.3V level, it needs to externally add a level conversion chip to achieve
level matching. The chip connection method can refer to the following circuit: