GSM/GPRS Module Series
M85 Hardware Design
M85_Hardware_Design Confidential / Released 37 / 88
Hardware flow control is disabled by default. When hardware flow control is required, RTS and CTS
should be connected to the host. AT command
AT+IFC=2,2
is used to enable hardware flow control. AT
command
AT+IFC=0,0
is used to disable the hardware flow control. For more details, please refer to the
document [1]
.
The Debug Port:
DBG_TXD: Send data to the COM port of computer.
DBG_RXD: Receive data from the COM port of computer.
The Auxiliary UART Port:
TXD_AUX: Send data to the RXD of DTE.
RXD_AUX: Receive data from the TXD of DTE.
The logic levels are described in the following table.
Table 6: Logic Levels of the UART Interface
Table 7: Pin Definition of the UART Interfaces
Parameter
Min.
Max.
Unit
V
IL
0
0.25×VDD_EXT
V
V
IH
0.75×VDD_EXT
V0.2
V
V
OL
0
0.15×VDD_EXT
V
V
OH
0.85×VDD_EXT
VDD_EXT
V
Interface
Pin Name
Pin No.
Description
Debug Port
DBG_RXD
43
Receive data
DBG_TXD
42
Transmit data
UART Port
DCD
45
Data carrier detection
RI
46
Ring indication
NOTE
