Smart Machine Smart Decision
Table 7: Serial port and Debug pin definition
Pin name
Pin number
Function
DTR
3
Data terminal ready
RI
4
Ring indicator
DCD
5
Data carrier detect
CTS
7
Request to send
RTS
8
Clear to send
TXD
9
Transmit data
Serial port
RXD
10
Receive data
DBG_TXD
27
Debug port
DBG_RXD
28
Used for debug
VBUS
6
USB power supply
USB_DP
23
USB differential data, (+) side
USB port
USB_DM
24
USB differential data, (-) side
Note: Hardware flow control is disabled by default. AT command “AT+IFC=2, 2”can enable hardware flow
control. AT command “AT+IFC=0, 0”can disable hardware flow control. For more details please refer to
document [1]
Table 8: Serial port characteristics
Symbol
Min
Max
Unit
V
IL
0.3
V
V
IH
2.5
V
V
OL
0.1
V
V
OH
2.7
2.8
V
4.4.1
Function of Serial Port
Serial port:
z
Full mode device.
z
Contains data lines TXD and RXD, hardware flow control lines RTS and CTS, status lines DTR, DCD and
RI.
z
Serial port can be used for AT communication.
z
Serial port supports the following baud rates:
115200bps.
z
Synchronization between DTE and DCE:
When DCE powers on with baud rates 115200bps, it is recommended to send "AT" or "at" or "aT" or "At"
command, until DTE receives the "OK" response, which means DTE and DCE are correctly synchronized.
4.4.2
Serial Interfaces
The following figure shows the connection between module and client (DTE).
SIM2000S_Hardware_Design_V1.00
25
2014-02-27