Service Guide

LTE Standard Module Series
EG915U_Series_Hardware_Design 20 / 81
MAIN_DCD
38
DO
Main UART data carrier
detect
V
OL
max = 0.45 V
V
OH
min = 1.35 V
MAIN_TXD
35
DO
Main UART transmit
V
OL
max = 0.45 V
V
OH
min = 1.35 V
MAIN_RI
39
DO
Main UART ring
indication
V
OL
max = 0.45 V
V
OH
min = 1.35 V
MAIN_DTR
30
DI
Main UART data terminal
ready
V
IL
min = -0.3 V
V
IL
max = 0.6 V
V
IH
min = 1.26 V
V
IH
max = 2.0 V
Auxiliary UART Interface
Pin Name
Pin No.
I/O
Description
DC Characteristics
comment
AUX_TXD
27
DO
Auxiliary UART transmit
V
OL
max = 0.45 V
V
OH
min = 1.35 V
1.8 V power
domain.
If unused, keep it
open.
AUX_RXD
28
DI
Auxiliary UART receive
V
IL
min = -0.3 V
V
IL
max = 0.6 V
V
IH
min = 1.26 V
V
IH
max = 2.0 V
1.8 V power
domain.
If unused, keep it
open.
Debug UART Interface
Pin Name
Pin No.
I/O
Description
DC Characteristics
Comment
DBG_RXD
22
DI
Debug UART receive
V
IL
min = -0.3 V
V
IL
max = 0.6 V
V
IH
min = 1.26 V
V
IH
max = 2.0 V
1.8 V power
domain.
If unused, keep it
open.
DBG_TXD
23
DO
Debug UART transmit
V
OL
max = 0.45 V
V
OH
min = 1.35 V
I2C Interface
Pin Name
Pin No.
I/O
Description
DC Characteristics
Comment
I2C _SCL
40
OD
I2C serial clock
External pull-up
resistor is
required.
1.8 V only.
If unused, keep it
open.
The I2 C
interface
supports
simultaneous
I2C _SDA
41
OD
I2C serial data