H350 LGA Serials Module Hardware User Manual Page 27 of 37
USB_DP and USB_DM are high speed lines, the highest transmit speed is 480 Mbps.
PCB Layout notice:
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.
UART2 doesn’t support MUX.
UART1 and UART2 signal description:
UART1
Pin#
Pin Name
I/O
Description
12
UART1_RI
O
UART1 Ring Indicator
56
UART1_DSR
I
UART1 DTE Ready
55
UART1_DTR
O
UART1 DCE Ready
57
UART1_DCD
O
UART1 Carrier Detect
10
UART1_CTS
I
UART1 Clear to send
11
UART1_RTS
O
UART1 Request to send
8
UART1_TXD
O
UART1 Transmitted Data
9
UART1_RXD
I
UART1 Received Data
