Adc Interface - Quectel EG915U Series Hardware Design

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Another example with transistor translation circuit is shown as follows. For the design of circuits in dotted
lines, please refer to that of the circuits in solid lines, but please pay attention to the direction of
connection.
MCU/ARM
NOTE
1. Transistor circuit solution is not suitable for applications with baud rates exceeding 460 kbps.
2. Please note that the module CTS is connected to the host CTS, and the module RTS is connected
to the host RTS.

4.7. ADC Interface

The module provides two analog-to-digital converter (ADC) interfaces. You can use AT+QADC=0 to read
the voltage value on ADC0 pin, AT+QADC=1 to read the voltage value on ADC1, See document [2] for
more details.
In order to improve the accuracy of ADC, the trace of ADC should be surrounded by ground.
EG915U_Series_Hardware_Design
Figure 23: Reference Circuit with Translator Chip
VDD_EXT
TXD
RXD
10K
VCC_MCU
RTS
CTS
GPIO
EINT
GPIO
GND
Figure 24: Reference Circuit with Transistor Circuit
4.7K
VDD_EXT
1 nF
10K
1 nF
VDD_EXT
4.7K
LTE Standard Module Series
Module
MAIN_RXD
MAIN_TXD
MAIN_RTS
MAIN_CTS
MAIN_DTR
MAIN_RI
MAIN_DCD
GND
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