Chengdu Ebyte Electronic Technology Co., Ltd
E32-900T20S User Manual
Copyright ©2012–2021
，
Chengdu Ebyte Electronic Technology Co.,Ltd.
8
22
RXD
Input
TTL UART inputs, connects to external (MCU, PC) TXD output pin.
23
TXD
Output
TTL UART outputs, connects to external RXD (MCU, PC) input pin.
24
AUX
Output
Used to indicate the working status of the module;
The user wakes up the external MCU and outputs low level during power-on
self-check initialization; (can be left floating)
25
VCC
-
Power supply: 2.3~ 5.5V DC
26
GND
-
Ground
4 Connect to MCU
No.
Description
（
STM8L MCU
）
1
The UART module is TTL level.
2
For some MCU works at 5VDC, it may need to add 4-10K pull-up resistor for the TXD & AUX pin.
