LTE Standard Module Series
EG91 Series Hardware Design
EG91_Series_Hardware_Design 55 / 106
Table 21: Default Behaviors of RI
State Response
Idle RI keeps at high level
URC RI outputs 120ms low pulse when a new URC returns
3.18. USB_BOOT Interface
EG91 series module provides a USB_BOOT pin. Customers can pull up USB_BOOT to 1.8V before
VDD_EXT is powered up, and the module will enter emergency download mode when it is powered on. In
this mode, the module supports firmware upgrade over USB interface.
Table 22: Pin Definition of USB_BOOT Interface
Pin Name Pin No. I/O Description Comment
USB_BOOT 75 DI
Force the module to enter
emergency download mode
1.8V power domain.
Active high.
It is recommended to
reserve test point.
The following figures show the reference circuit of USB_BOOT interface and timing sequence of entering
emergency download mode.
Module
USB_BOOT
VDD_EXT
4.7K
Test point
TVS
Close to test po int
Figure 28: Reference Circuit of USB_BOOT Interface
To Next Page
Loading...
Need help?
General
