User's Manual

Smart Machine Smart Decision
SIM7100A_User Manual_V1.01 2014-12-11
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Table 12: UART Pin description
Pin type Pin name Pin No. I/O Default Status
UART1
RXD 68 I Pull-Down
TXD 71 O Pull-Up
RTS 66 O Pull-Up
CTS 67 I Pull-Down
DTR 72 I Pull-Up
DCD 70 O Pull-Up
RI 69 O Pull-Up
More pin information refers to chapter 2.2.
Table 13: UART Pin Logic level
Symbol Parameter
Min Typ Max Unit
V
IH
High-level input voltage
1.26 1.8 2.1 V
V
IL
Low-level input voltage
-0.3 0 0.63 V
V
OH
High-level output voltage
1.35 - 1.8 V
V
OL
Low-level output voltage
0 0 0.45 V
3.3.1 RI Behavior
If UART port is used in Null Modem, the pin “RI” can be used as an interrupt signal to HOST. Normally it
will keep high logic level until certain condition such as receiving SMS, voice call (CSD, video) or URC
reporting, then “RI” will change to low logic level to inform the master (client PC). It will stay low until
the master clears the interrupt event with AT command.
Figure 13: RI behaviour in NULL Modem