Quectel RG520N-AT - Page 58

5G Module Series
RG520N-AT_Hardware_Design 57 / 109
VCCA VCCB
OE
A1
A2
A3
A4
A5
A6
GND
B1
B2
B3
B4
B5
B6
VDD_1V8
MAIN_RI
MAIN_DCD
MAIN_RXD
MAIN_DTR
MAIN_TXD
51K
51K
0.1 μF
0.1 μF
RI_MCU
DCD_MCU
RXD_MCU
DTR_MCU
TXD_MCU
VDD_MCU
Translator
Figure 28: Reference Circuit with a Voltage-level Translator
Another example with transistor circuit is shown as below. For the design of circuits shown in dotted lines,
see that shown in solid lines, but pay attention to the direction of connection.
MCU/ARM
TXD
RXD
VDD_1V8
10K
VDD_MCU
4.7K
10K
VDD_1V8
MAIN_RXD
MAIN_TXD
MAIN_DTR
MAIN_RI
GND
GPIO
MAIN_DCD
Module
GPIO
EINT
VDD_1V8
4.7 K
GND
1 nF
1 nF
Figure 29: Reference Circuit with Transistor Circuit
1. Transistor solution is not suitable for applications with baud rates exceeding 460 kbps.
2. Other baud rates of the main UART are under development.
3. Please note that the module’s BT_CTS is connected to the peripheral’s CTS, and the module’s
BT_RTS is connected to the peripheral’s RTS.
NOTE