Neo_M660A GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
16
3.2
UART
Table 3-2
UART
Pin Name
I/O
Function Description
Remarks
RTS
DO
Request to send
CTS
DI
Clear to send
URXD
DI
UART data receive
UTXD
DO
UART data transmit
UART is used for AT commands, data sending/receiving, firmware updating, etc.
Figure 3-12 shows the signal connection between the module (DCE) and the terminal (DTE).
Figure 3-12
Signal connection between DCE and DTE
DCE
URXD
UTXD
CTS
RTS
DTE
UTXD
URXD
RTS
CTS
The UART of M660A works at
2.8 V
CMOS logic level. The voltages for input high level should
not
exceed 3.1 V. Supported baud rates range from 300 bit/s to 921600 bit/s and the default rate is
115200 bit/s
.
For more details about baudrate, see
Neo_M660A GPRS Module Hardware User Guide
.
If the UART is interfacing with an MCU that has 3.3 V logic levels, resistors should be connected in series
with the signals.
