CLM920 TD3 LTE Module Hardware Usage Guide
Shanghai Yuge Information Technology co., LTD
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3.6.2 Debug serial port
The 11th and 12th pins of the module are debug serial port pins, and the debug serial port
supports 115200bps baud rate. It is used for Linux control and log printing. It can reserve test
points for module debugging. Please do not leave it floating.
Table 3-11 Debugging serial port pin definitions
Pin
Signal name
I/O Description
Param
eter
Level value (V)
Rem
arks
Min
Typical
Max
11
DBG_RXD
DI
UART data
reception
VIH
1.2
1.8
2
VIL
-0.3
0.6
12
DBG_TXD
DO
UART data
transmission
VOH
1.35
1.8
2
VOL
0
0.45
3.6.3 RI and DTR interface
The CLM920 TD3 module supports the serial sleep wake-up function, and the RI pin can
be used as an interrupt to wake up the host.
RI:
The RI pin can wake up the host as an interrupt.
The RI pin idle state is low. When a short message or voice incoming call is received, the
RI outputs a rectangular wave with a period of 500ms (high level for 250ms, low level for
250ms) to wake up the host.
Figure 3-15 RI pin signal waveform
DTR:
The DTR pin can be used as the sleep wake-up pin of the CLM920 TD3 module. When
the module enters sleep, the DTR pin can be pulled low to wake up the module.
Pull the DTR pin high first.
