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UMTS/HSPA+ Module Series
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4.2. USB_BOOT Interface
The module provides a USB_BOOT pin. You can pull up USB_BOOT to VDD_EXT before powering on
the module, thus the module will enter emergency download mode when powered on. In this mode, the
module supports firmware upgrade over USB interface.
Table 13: 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 point
Figure 17: Reference Circuit of USB_BOOT Interface
Pin Name
Pin No.
I/O
Description
Comment
USB_BOOT
115
DI
Forces the module to enter
download mode
1.8 V power domain.
Active High.
It is recommended to
reserve test points.