Product Info

LTE Standard Module Series
EC25 Hardware Design
EC25_Hardware_Design 68 / 112
Table 24: Pin Definition of USB_BOOT Interface
The following figure shows a reference circuit of USB_BOOT interface.
Module
USB_BOOT
VDD_EXT
4.7K
Test point
TVS
Close to test po in t
Figure 31: Reference Circuit of USB_BOOT Interface
V
IL
≤
0. 5 V
V
H
=0.8V
VBAT
PWRKEY
≥
500ms
RESET_N
NOTE
VDD_EXT
About 100ms
USB_BOOT
Setting USB_BOOT to high level between VBAT rising
on and VDD_EXT rising on can let the module enter
into emergency download mode.
Figure 32: Timing Sequence for Entering into Emergency Download Mode
Pin Name Pin No. I/O Description Comment
USB_BOOT 115 DI
Force the module to enter into
emergency download mode
1.8V power domain.
Active high.
It is recommended to
reserve test point.