Service Guide

LTE Standard Module Series
EG91_Series_Hardware_Design
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1. Keep all RESERVED pins and unused pins unconnected.
2. BOOT_CONFIG pins (SPI_CLK, USB_BOOT, PCM_CLK, PCM_SYNC) cannot be pulled up before
startup.
3.4. Operating Modes
The table below briefly outlines the operating modes to be mentioned in the following chapters.
Other Pins
Pin Name
Pin
No.
I/O Description
DC
Characteristics
Comment
W_DISABLE# 18 DI
Airplane mode
control
V
IL
min = -0.3 V
V
IL
max = 0.6 V
V
IH
min = 1.2 V
V
IH
max = 2.0 V
1.8 V power domain.
Pull-up by default.
At low voltage level,
module can enter
airplane mode.
If unused, keep it open.
AP_READY 19 DI
Application
processor ready
V
IL
min = -0.3 V
V
IL
max = 0.6 V
V
IH
min = 1.2 V
V
IH
max = 2.0 V
1.8 V power domain.
If unused, keep it open.
USB_BOOT 75 DI
Force the module to
enter emergency
download mode
V
IL
min = -0.3 V
V
IL
max = 0.6 V
V
IH
min = 1.2 V
V
IH
max = 2.0 V
1.8 V power domain.
It is recommended to
reserve the test points.
NC and RESERVED Pins
Pin Name
Pin
No.
I/O Description
DC
Characteristics
Comment
NC 1, 2, 11–14, 16, 51, 57, 63–66, 76–78, 88, 92–99
Keep these pins
unconnected.
RESERVED 25, 56
Keep these pins
unconnected.
Pin 56 is only reserved
on EG91-E.
NOTE