N723-EA Hardware User Guide
Chapter 5 Application Interfaces
Copyright © Neoway Technology Co., Ltd. All rights reserved.
36
Figure 5-12
Hardware shutdown process
PWRKEY_N
VBAT
UART
VDD_1P8
≈
3.75s
T
≥
18s
≈
310ms
Active
Off
Inactive
Indefinite
When the module executes the shutdown process, VDD_1P8 stops the voltage output after the UART port
completes the shutdown process. The low pulse width needed for RESET_N hard shutdown may slightly vary
with the module software.
5.2.3
USB_BOOT
USB_BOOT is the pin to forcibly enter the download mode. Connect USB_BOOT to GND through a
pull-down resistor after the module is started, and the module will enter forcible download mode. This
is the last method to handle issues that result in startup or running failures. It is recommended to
reserve this pin (as a button or a test point) to facilitate software upgrades and debugging.
The following figure shows a reference design of USB force download:
Figure 5-13
Reference design of USB force download
USB_BOOT
N723-EA
Module
TVS
D1
470
Ω
R1
Test point
C1
0.1
μF