Quectel M12

M12 Hardware Design
M12_Hardware_Design_V3.3 - 44 -
MCU/ARM
/TXD
/RXD
VDD_EXT
4.7K
VCC_MCU
4.7K
5.6K
4.7K
VDD_EXT
TXD
RXD
RTS
CTS
DTR
RI
/RTS
/CTS
GND
GPIO DCD
Module
GPIO
EINT
VCC_MCU
Voltage level: 5V
4.7K
GND
Figure 25: 5V level match circuit
The following picture is an example of connection between module and PC. A RS232 level shifter
IC or circuit must be inserted between module and PC, since these three UART ports do not
support the RS232 level, while support the CMOS level only.
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