User's Manual

Table Of Contents
SIM7090G User Manual V1.01
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3.3.1. UART Design Guide
The following figures show the reference design.
Figure 10: UART full modem
Driving the host DTR to low level will wake up the module.
AP_READY will detect the sleep state of the host (can be configured to high level or low level
detection).
Table 13: UART electronic characteristic
Symbol
Description
Min.
Typ.
Max.
Unit
V
IH
UART input high level voltage
1.17
1.8
2.1
V
V
IL
UART input low level voltage
-0.3
0
0.63
V
V
OH
UART output high level voltage
1.35
1.8
1.8
V
V
OL
UART output low level voltage
0
0
0.45
V
The SIM7090G UART is 1.8V voltage interface. If users UART application circuit is 3.3V voltage interface,
the level shifter circuits should be used for voltage matching. The following figure shows the voltage
matching reference design.