Chengdu Ebyte Electronic Technology Co., Ltd.
E22-900T30S1C User manual
Copyright ©2012–2018，Chengdu Ebyte Electronic Technology Co.,Ltd.
8
3 Size and pin definition
No.
Name
Direction
Function
1
M0
Input
（weak pull-up）
Work with M1 to decide 4 working modes of module (not suspended, if not
used, could be grounded).
2
M1
Input
（weak pull-up）
Work with M0 to decide 4 working modes of module (not suspended, if not
used, could be grounded).
3
RXD
Input
TTL UART inputs, connects to external (MCU, PC) TXD output pin. Can be
configured as open-drain or pull-up input. Ground
4
TXD
Output
TTL UART outputs, connects to external RXD (MCU, PC) input pin. Can be
configured as open-drain or push-pull output
5
AUX
Output
To indicate module ’ s working status & wakes up the external MCU.
During the procedure of self-check initialization, the pin outputs low level.
Can be configured as push-pull output (can be suspended).
