Smart Machine Smart Decision
SIM5360_Hardware Design_V1.01
2013-11-22
29
Figure 18: Null modem
3.3.1
Pin Description
Table 8: Pin description
Pin type
Pin name
Pin No.
I/O
Active voltage
Default Status
UART
UART_RXD
68
I
High/Low
Pull-Down
UART_TXD
71
O
High/Low
Pull-Up
UART_RTS
66
O
High/Low
UART_CTS
67
I
High/Low
Pull-Up
UART_DTR
72
I
High/Low
Pull-Up
UART_DCD
70
O
High/Low
UART_RI
69
O
High/Low
More pin information refers to chapter 2.2.
Table 9: Logic level
Parameter
Min
Max
Unit
Logic low input
-0.3
0.63
V
Logic high input
1.17
2.0
V
Logic low output
0
0.45
V
Logic high output
1.35
1.8
V
3.3.2
Application Guide
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
