Specifications

M80 Hardware Design
M80_HD_V1.0 - 50 -
3.9.4. UART Application
The reference design of 3.3V level match is shown as below. 1K resistors among the following
diagram are used to decrease the output voltage of MCU/ARM.
MCU/ARM
/TXD
/RXD
1
K
TXD
RXD
RTS
CTS
DTR
RI
/RTS
/CTS
GPIO
EINT
voltage level: 3.3V
1K
1K
GND
VBAT
GPIO
STATUS
MODULE
Figure 24: 3.3V level match circuit
Note: The above reference design is also suitable for 3V system.
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