Chengdu Ebyte Electronic Technology Co., Ltd.
E22-900T22D User Manual
Copyright ©2012–2018，Chengdu Ebyte Electronic Technology Co.,Ltd.
7
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.
4
TXD
Output
TTL UART outputs, connects to external RXD (MCU, PC) input pin. Can be
