User's Manual
Table Of Contents

H350 LGA Serials Module Hardware User Manual Page of
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5.4.2 USB Interface Application
Reference Design:
Figure 5- 7 USB Interface Reference Design
T101 and T102 should be low capacitor TVS, it is below 1pF. No special requirement for T103.
VUSB is USB power supply, Recommend power supply range is 3.3V ~ 4.5V. Please don’t float pin
VUSB, or USB can’t be detected.
USB_DP and USB_DM are high speed differential lines, the highest transmit speed is 480 Mbps.
PCB Layout note:
USB_DP and USB_DM lines need equal length, parallel, as short as possible.
The input and output need GND isolation.
The layout design of this circuit on the AP board should comply with the USB 2.0 high speed protocol,
With differential lining and impedance control to 90 ohm.
5.5 UART Interface
5.5.1 UART Interface Description
H350 wireless communication module provides two UART, one is 8 wire serial bus interface, and the
other is a 2 wire serial bus interface.
8 wire serial bus interface (UART1) supports flow control; users can download software or send/receive
AT through UART1. 2 wire serial bus interface (UART2) supports a few AT Commands.
Note:
UART2 only supports some common query functions.
UART2 doesn’t support hardware flow control, no CTS, RTS, DTR, DSR, DCD, RI pin.